UNIVERSITY OF FLORIDA THESIS OR DISSERTATION...
Transcript of UNIVERSITY OF FLORIDA THESIS OR DISSERTATION...
DATA SHARING AND THE WEB: A TEST CASE FOR THE ARCGIS VIEWER FOR FLEX
By
DANIEL ALAN DOWNING
A FINAL PROJECT PRESENTED TO THE GRADUATE SCHOOLOF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN URBAN AND REGIONAL PLANNING
UNIVERSITY OF FLORIDA
2016
To my family and friends. A special feeling of gratitude to my wife Sidney and to my parents David Downing and Gail Anders.
ACKNOWLEDGMENTS
I would like to thank my committee members Paul Zwick and Stanley Latimer.
Their encouragement over the many years this journey has taken was paramount to me
reaching the finish line. A very special thanks to Crystal Goodison for her guidance
during the writing and editing process. I’d like to thank Sam Palmer and Kate Norris, my
longtime friends and colleagues at the GeoPlan Center, for all the knowledge they have
shared with me while working together. A special thanks to Lex Thomas for giving me
the opportunity to work at the GeoPlan Center with such an amazing group of intelligent
and talented individuals. Lex has been a mentor in both my work and personal life. I’d
like to acknowledge my good friend William Cory Swales who introduced me to the field
of GIS and lead me to the University of Florida.
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TABLE OF CONTENTS
page
ACKNOWLEDGMENTS...................................................................................................4
LIST OF TABLES.............................................................................................................6
LIST OF FIGURES...........................................................................................................7
LIST OF ABBREVIATIONS..............................................................................................9
ABSTRACT....................................................................................................................10
INTRODUCTION............................................................................................................11
LITERATURE REVIEW..................................................................................................13
ArcGIS Online..........................................................................................................15ArcGIS Viewer for Flex............................................................................................16ArcGIS Viewer for Silverlight....................................................................................17Open Source Options..............................................................................................18
METHODOLOGY...........................................................................................................20
Creating ArcGIS Server Services............................................................................21Creating the Flex Application...................................................................................23
Maps..................................................................................................................23Widgets.............................................................................................................24Layout................................................................................................................26Design...............................................................................................................27Preview..............................................................................................................28
Using the Viewer Application...................................................................................28
DISCUSSION.................................................................................................................41
CONCLUSION...............................................................................................................48
LIST OF REFERENCES................................................................................................51
BIOGRAPHICAL SKETCH.............................................................................................53
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LIST OF TABLES
Table page
Table 2-1........................................................................................................................20
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LIST OF FIGURES
Figure page
Figure 3-1.......................................................................................................................31
Figure 3-2.......................................................................................................................31
Figure 3-3.......................................................................................................................32
Figure 3-4.......................................................................................................................32
Figure 3-5.......................................................................................................................33
Figure 3-6.......................................................................................................................33
Figure 3-7.......................................................................................................................34
Figure 3-8.......................................................................................................................34
Figure 3-9.......................................................................................................................35
Figure 3-10.....................................................................................................................35
Figure 3-11.....................................................................................................................36
Figure 3-12.....................................................................................................................36
Figure 3-13.....................................................................................................................37
Figure 3-14.....................................................................................................................37
Figure 3-15.....................................................................................................................38
Figure 3-16.....................................................................................................................38
Figure 3-17.....................................................................................................................39
Figure 3-18.....................................................................................................................39
Figure 3-19.....................................................................................................................40
Figure 3-20.....................................................................................................................40
Figure 4-1.......................................................................................................................47
Figure 4-2.......................................................................................................................47
Figure 4-3.......................................................................................................................48
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Figure 4-4.......................................................................................................................48
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LIST OF ABBREVIATIONS
EC2 Amazon.com’s cloud computing platform.
Esri Environmental Systems Research Institute. An international supplier of geographic information system software.
GIS Geographic information system.
RIA Rich internet application. A Web application that mimics the capabilities of desktop software applications.
S3 Amazon.com’s online file storage web service.
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Abstract of Final Project Presented to the Graduate Schoolof the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Arts in Urban and Regional Planning
DATA SHARING AND THE WEB: A TEST CASE FOR THE ARCGIS VIEWER FOR FLEX
By
DANIEL ALAN DOWNING
August, 2016
Chair: Paul ZwickCochair: Stanley LatimerMajor: Urban and Regional Planning
Data sharing is an important component of research fields and the planning
profession. This project examines the feasibility of the ArcGIS Viewer for Flex as a tool
for data sharing on the web and enhancing collaboration for planners and researchers
with no web development knowledge. Web sharing tools are surveyed to determine
their strengths and limitations and justifications are made for the selection of the ArcGIS
Viewer for Flex. The ArcGIS Viewer for Flex is proven to be a capable stand-alone
product for sharing data on the web, however, the future of web GIS and data sharing is
concluded to reside in newer cloud based platforms.
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CHAPTER 1INTRODUCTION
Data sharing is simply making data accessible to others who have interest in it.
Whether the data results from scholarly studies or a local government’s master plan, the
ability to share results with colleagues and the public is very important. For the specific
purposes of this project, data sharing will be defined as the ability to display, overlay,
and query spatial data on the web and make it accessible to anyone with an internet
connection and a web browser. The concept of data sharing is important for a number
of reasons. The free flow of information, including data, analysis, and results is key to
the advancement of academic research. One common problem with spatial data is that
it is often kept in proprietary formats and the data can be extremely large in file size.
Spatial data also requires special software to view and analyze and often cannot be put
on the internet without knowledge of computer coding. These problems restrict access
to the data. Often this data ends up being presented in static maps in papers and
presentations. Simplified online sharing of spatial data with no coding knowledge allows
for easy access to data and allows for interactive examination and comparison of
research results. It also allows for public review and the ability to help the lay person
understand project goals, often helping to gain consensus among decisions makers and
those affected by their decisions.
This particular data sharing research is directed toward users of Esri’s ArcGIS
spatial products. The aim of this project is to provide a test case of the ArcGIS Viewer
for Flex and examine its benefits and limitations in regards to data sharing on the web.
The ArcGIS Viewer for Flex is part of a software framework which provides generic
functionality that can be manipulated to provide application specific software. Any
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spatial data researcher or planner with a need to share their research or projects can
benefit from the results of this project.
This paper will review the current research on web GIS and data sharing and
provide justification of the ArcGIS Viewer for Flex as the chosen test case. The
methodology section will detail the technical implementation of an ArcGIS Viewer for
Flex site, including installation, site creation, and management, as well as the creation
of ArcGIS for Server map services. The discussion section will show the results of the
finished ArcGIS Viewer for Flex site and discuss how well the test case has met the
goal of providing a data sharing platform with no computer coding necessary. Finally,
the conclusion will discuss where this research can go in the future and what methods
and platforms look most likely to be widely adopted.
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CHAPTER 2LITERATURE REVIEW
Collaboration is an important part of any field of study. Within the field of
planning, web GIS has made sharing data and analysis results an integral part of the
planning process. This leads to more information for both decision makers and the
public. This literature review will detail the current research on the importance of web
GIS to data sharing and its benefits, discuss the barriers many organizations face in
setting up a web GIS system, and finally review current frameworks for web GIS
implementation.
According to Peterson (2009), “Many web GIS researchers contend that the
future of cartography is largely tied to the development of tools for online mapping“ (p.
1). GIS technology has been moving towards internet capable services for many years
now as Peng (2003) notes, “The advancement of technologies has led to a paradigm
shift from collecting data and finishing a GIS project on a desktop to considering
universal accessibility and remotely distributed data and analysis functions” (preface,
xxx) Despite this movement towards online availability of GIS related data and maps,
there are still many situations where data is restricted:
This restricted access to data leads to ineffective use of resources and is a retardant for growth. The need exists in many organizations for user-friendly web map services systems to be put in place to make this data available on the internet (Brynard, 2013, p. 1).
Lack of access to data is very common in developing nations, but is also a common
problem throughout the developed world. Without easy access to data, interdisciplinary
collaboration is hard to accomplish. “Much of the data generated by the custodian
organizations require inputs from other disciplines or their data constitutes an essential
component in the scientific pursuits of other organizations” (Brynard, 2013, p. 1).
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Internet GIS can solve many of the data access problems which can hinder data
sharing and collaboration:
Modern software systems provide the facilities to serve spatial data on the web where it can be made readily accessible either to selected clients or to a wider audience. What is really required is corporate commitment, and champions within the organization to drive the process (Brynard, 2013, p. 2).
Collaboration is not the only benefit of adopting web GIS. For those moving from
previously static maps which were simply printed or transferred as images or pdfs,
Dragicevic (2004) found “In the Web-based environment with basic GIS functionalities,
the map becomes dynamic, interactive and accessible to a wide selection of users as a
visual communication tool” (p. 80). Dragicevic (2004) also notes, “Web-based GIS has
enhanced the open use of GIS in three main directions: (1) spatial data access and
dissemination, (2) spatial data exploration and geovisualization, and (3) spatial data
processing, analysis and modeling” (p. 80). The expansion of GIS in web based tools
will also spur developments in other technologies. “Web-based GIS enhances the
potential for further developments in other areas such as spatial analysis and modeling,
wireless and mobile services, 3D data access and query that are anticipated to
experience increased research focus in the coming years” (Dragicevic, 2004, p. 81).
Despite the many benefits of web GIS, there are still numerous barriers to entry
for both organizations and individuals looking for the ability to share their data.
According to Maclachlan (2007), “Many communities lack the resources to fully support
the implementation of in house GIS” (p. 72). GIS mapping and analysis can require
sophisticated software, heavy-duty hardware, a steep learning curve, and a substantial
time commitment. Along with the steep learning curve and time commitment, the
decision of which web GIS platform to use is also a challenge. Myers and Ralston
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(2012) concluded, “There is no one best set of tools, and choices often reflect the
developer’s experience and preferences. Current rich internet application (RIA)
development is dominated by frameworks available in Flex, Silverlight, and to a lesser
extent, JavaFX” (p. 41). All of these web GIS development frameworks have their own
positives and negatives.
Many planners in today’s work environment are tasked with sharing spatial data
and results with project collaborators and the public. Much of the data involved is
detailed and changes frequently. Spatial data sharing solutions need to be cost
effective, customizable, and created and maintained by professionals without the
technical knowledge to build these systems from scratch.
The following is a comparison of some of the most common commercial and
open source products for building web GIS systems. It is important to recognize that
web GIS applications have both a “front-end” and a “back-end”. The “front-end” is the
user interface, or what the user sees and interacts with via a web browser. The user
interface is typically a dynamic map, where spatial data is viewable and the user can
interact with the map. The “back-end” of the application contains the server and
database components, where data is stored and served out for client consumption. It
will be noted which options provide both components and which need additional
components to provide a full web GIS experience.
ArcGIS Online
ArcGIS Online is a cloud-based platform where users can upload their data and
create visualizations directly from their web browser. The back-end of the application is
provided by Amazon’s EC2 and S3 compute and storage services providing a highly
reliable and scalable server infrastructure. The front-end is a web map with tools that
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allow you to create, manage, and share GIS data as services. The service is
subscription based and users are allotted a number of credits based on the subscription
level. As features of ArcGIS online are used, such as storage, geocoding, or spatial
analysis, payment for them is deducted from the user’s pool of available credits. ArcGIS
online is a strong candidate as it requires no special hardware and very little technical
expertise to produce shareable maps and data. The biggest drawback is customization.
The front end cannot be customized and there are very few built in map tools available.
This restricts use of the application primarily to visualization alone.
ArcGIS Viewer for Flex
The ArcGIS Viewer for Flex is a framework for building web GIS applications that
are easily customizable with no programming required. The ArcGIS Viewer for Flex is
free of charge; however to create a fully functioning web GIS experience, a web server
is necessary. The ArcGIS Viewer for Flex is meant to be built on top of ArcGIS for
Server as the back-end and is supported and updated to match the functionality of
ArcGIS for Server. A license is required to use ArcGIS for Server. The ArcGIS Viewer
for Flex is built with Adobe Flash technology. Leinert (2012) has described the
advantages of the Flash framework:
Advantages of the Flash framework include the performant rendering engine, the integration of multimedia content (e.g., video, sound and animation), a wide range of auxiliary tools for designers, and the wide-spread dissemination of the Flash Player for rendering Flash content (p. 26).
The use of the Flash framework also has some notable disadvantages concerning code
changes and security noted by Bradbury (2010):
Among the disadvantages of Adobe Flash, there are the dependency on one software vendor who may arbitrarily change the code base or the functionality of tools and plug-ins. Also, security concerns are raised when using a plug-in, particularly in regard to arbitrary, remote code execution and passing on of cached user information (p. 34).
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The ArcGIS Viewer for Flex provides middle ground between building your own
application from scratch and the standard off the shelf software: “The flexviewer
delegates mapping tasks in a manner that allows for easy code maintenance, minimizes
friction among programming modules, and liberates programmers from the development
complexity of managing maps, map navigation tools, application configurations, and
component communication” (Zhang, 2008, p. 9). The front-end is created using an
interactive application builder that allows for high levels of customization and additional
functionality all without having to write any code. The ArcGIS Viewer for Flex also has
the benefit of a large support community including samples, forums, and help guides.
The source code has also been made freely available adding a benefit that is often
reserved for open source options.
ArcGIS Viewer for Silverlight
The ArcGIS Viewer for Silverlight is an Esri product built on Microsoft’s Silverlight
framework. This option is very similar to the ArcGIS Viewer for Flex. It is free of charge,
but requires a web server to run. It is built to work with ArcGIS for Server as the back-
end and uses an application builder to create highly customizable front-ends with no
coding necessary. Advantages of the ArcGIS Viewer for Silverlight include “the
performant rendering engine, the integration of multimedia content, and the availability
of auxiliary tools for programmers…” (Lienert, 2012, p. 26). It also shares a similar
disadvantage with Adobe Flash in terms of the dependency on one single software
vendor (Lienert, 2012, p. 27). Microsoft Silverlight is a newer technology than Adobe
Flex. In general, this means that there are fewer resources and samples available
online for Silverlight. Also the source code for the ArcGIS Viewer for Silverlight is not
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publicly available like the ArcGIS Viewer for Flex. This restricts further customization
outside of what is available through the application builder.
Open Source Options
There a number of open source options for creating a web GIS system. The open
source model provides free access to the product as well as the ability to build upon or
alter it. Some popular examples for open source back-end web GIS tools are
GeoServer, Mapguide, Mapnik, and Mapserver, and for the front-end there are
Openlayers, Geomajas, and GeoExt. For the purposes of this discussion I will treat
these as one option as they have many of the same benefits and disadvantages. The
major benefit that is immediately apparent with the open source options is the cost of
operation, which is free. Along with cost savings, “there are other well-known benefits of
open source software such as vendor independence and open standards” (Steiniger &
Hunter, 2013, p. 146). But there are also a number of barriers, such as knowledge
barriers, legacy integration, forking, sunk costs and technology immaturity (Nagy,
Yassin, & Bhattacherjee, 2010, p.1). Legacy integration involves integrating legacy data
into a new open system. Forking occurs when open source projects branch from each
other, creating separate tools that no longer work together. Sunk costs involve the lost
value from previous investments in proprietary systems. The biggest barrier to
overcome for the everyday planner will most likely be the knowledge barrier. Front-end
development is very heavily code based when using these open source options.
Platforms with a GUI (Graphical User Interface) application builder are much more
suitable for many less tech savvy planners. This eliminates many of the of the open
source options.
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The ArcGIS Viewer for Flex was chosen as this project’s test application due to
its highly customizable interface, built-in tools, and more extensive availability of the
online support resources. ArcGIS online was not a viable option due to its lack of
customization options. ArcGIS Viewer for Silverlight was also not a viable option due to
the lack of online support resources. The open source software options were not
chosen because of the steep learning curve associated with application development
and code writing. Table 2-1 summarizes the benefits and disadvantages of the reviewed
software packages for creating a web GIS with collaborative goals for the everyday
planner.
Table 2-1
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CHAPTER 3METHODOLOGY
For this test application of the ArcGIS Viewer for Flex, a fully functional flexviewer
site was created and implemented. The purpose of the web application that was created
was to display and share the results of LUCIS modeling in Hillsborough County. LUCIS
stands for Land-Use Conflict Identification Strategy and is a GIS model that produces
representations of possible future land use patterns. The data used served as a great
example of the capabilities of the platform, but any data could have been used for this
test application.
The ArcGIS Viewer for Flex can display web enabled services in an easily
configurable and accessible viewer. The following assumptions were made prior to site
creation:
There is a web server running on the machine where the viewer is
installed.
The user has read/write access to the folders containing the viewer
application.
There is access to ArcGIS for Server.
An ArcGIS Viewer for Flex website was created using the application builder, which is a
light weight, xml based viewer. It requires no coding knowledge to get up and running.
The viewer can be downloaded from Esri’s website at:
http://resources.arcgis.com/en/communities/flex-viewer/.
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An Esri Global Account is necessary to download the flex application builder. Finally,
before the application builder can be installed adobe AIR must be installed on the
server. Adobe AIR is available at: http://get.adobe.com/air/
Upon first open, the application builder verifies the Web Server Base Folder, or
the folder on your server where the application files will be stored and the Web Server
Base Folder URL, which is the web URL that will be entered externally to get to the site.
Before building the viewer, it is recommended to prepare and create the ArcGIS for
Server map services that will be used in the application.
Creating ArcGIS Server Services
The planning process involves many different types of data. This test application
map viewer included basemaps and operational layers. Operational layers are the
layers produced by the site creator that need to be shared. They can include both vector
and raster data are intended primarily to be data that changes frequently. All data
included in the map viewer were published as ArcGIS for Server map services. Creating
map services is a relatively simple process that is done using a tool in ArcMap. For this
example, a single map service will be created from some sample suitability map
surfaces created from the LUCIS model. First, the suitability data layers were added to
the table of contents in ArcMap which can be seen in Figure 3-1. These data layers
resided in a folder that ArcGIS Server has the proper permissions to access. If the
permissions access is unknown, it can be changed later when the service is analyzed.
The appearance of the layers in the MXD is also how they will appear in the
viewer application, so any changes made there will carry over to the published services.
The symbology of the layers as well as labels, scale dependent rending, layer names,
and layer visibility should all be set in the MXD. A map service can contain multiple
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data layers. All data to be shared can be in one MXD and published to a single service
in your application. If the data lends itself to logical groupings that need to be
maintained, then multiple services can be created. For example, in the test application
there are three separate services, one for suitability surfaces, one for operational layers,
and one for basemap data.
The layers in the MXD do not have to be turned on in the table of contents. It
may be preferable to have them off. This will allow the users of the application to
choose which layers to display on their own. It is ok if the map is blank; the data still
resides in the map and can be toggled on from the viewer interface. After the data was
prepared and symbolized, it was saved and then published using the “Share as Service”
tool. The “Share as Service” dialog can be seen in Figure 3-2 and the “Publish a
service” option in Figure 3-3.
Next, the connection to the ArcGIS Server instance (referenced in the
assumptions list) was chosen from the drop down menu. This determines the web
server where the map service will reside. Next, an existing file folder location on the
server was chosen to store the map service. Finally, the Service Editor, shown in Figure
3-4, was used to edit the service parameters. This is where the bulk of the map service
personalization is done, including: the ability to add metadata, create a cached data
service instead of a dynamic service, configure pooling and processes, and the ability to
add or remove service capabilities (WCS, WMS, Feature Access, Schematics, Mobile
Data Access, Network Analysis, KML, WFS).
For the purposes of this test application, the default settings were used. Before
the service was published, the analyze command at the top of the service editor was
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run. This tool inspects the MXD for common errors that can keep a service from being
published or slow down performance in general. After completion, the analyzer provides
feedback on any errors encountered and how to improve the service for reliability. For
this test application, the warnings and errors (Figure 3-5) were reviewed and resolved.
After resolution, the map service was published to the server by clicking the publish
button. Finally, the published services were added to the map viewer application
providing a powerful platform to display and share data.
Creating the Flex Application
The web application was created using the Application Builder tool shown in
Figure 3-6. The first step was to name the viewer application, after which the viewer
URL was assigned. Personalizing the web application is done through a series of tabs.
Each tab is described individually in the following sections.
Maps
A new application can be created from Web Maps or from Basemaps &
Operational Layers. The Web Maps option allows for the use of existing map services
available from ArcGIS Online. The test application used Basemaps & Operational
Layers to highlight user created data from the ArcGIS for Server map services that were
created earlier. The maps tab can be seen in Figure 3-7. The Basemaps & Operational
Layers page has 3 tabs:
Basemaps. For this test application, the featured basemaps from ArcGIS Online
were used as the base layer. All the available featured basemaps can be added or they
can be limited to only the ones that work with the data in the hosted services. The first
basemap that is added will be the default basemap shown when the application first
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opens. If multiple basemap options are chosen they will be available to the user through
the basemap switching widget.
Operational layers. The Operational Layers tab is where the services created
using ArcGIS for Server can be added to the application and configured. For this test
application, the map services of the suitability layers were added and configured.
Changes were made to the layer label, layer visibility, and transparency.
Map extent. This tab holds the configuration for the default map extent, or the
area of the map that is displayed when the application is first opened. The map extent
for the test application site area was set to include the geographic area encompassing
the operational layers. A map interface within this tab was used to set the map extent
for the test application.
Widgets
Widgets are prepacked tools that provide functionality to web mapping
applications and allow users to customize the capabilities of their applications. Widgets
are provided with the ArcGIS Viewer for Flex, but are also made available by community
developers. New widgets are added to the platform on a regular basis.
The Widgets page (Figure 3-8) contains a catalog of available built in widgets. These
include:
Bookmark widget - Spatial bookmarks for quick navigation.
Chart widget - Display charts for selected features.
Data Extract widget - Extracts data (export).
Draw widget - Quick drawing (i.e., redlining).
Edit widget - Allows you to edit any editable feature layers in the operational
layers.
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Geoprocessing widget - Allows you to use any geoprocessing task.
GeoRSS widget - Creates layers based on a GeoRSS feed.
Layerlist widget - Displays the operational data in the Viewer application.
Legend widget - Displays a legend for the layers you chose.
Locate widget - Allows address geocoding.
Print widget - Advanced or simple printing of the current map.
Query widget - Displays clickable features based on a query to a layer from an
ArcGIS Server Map service or Feature service.
Search widget - Allows users to select a clickable feature to display on the map.
Similar to the Query widget, except the Query widget shows all the features by
default.
Time widget - Enables time animation of time-aware layers.
To include a widget in the application simply highlight it and click the include
button. Once any widgets have been added to the application they can be further
configured by clicking the edit pencil below the widget icons. The configuration page for
each widget is different, however, there are some items that are common to all widgets
that can be configured, for example, the widget label, the widget icon, and whether the
widget is opened or closed by default when the application opens. The widgets that
were used in the test application were the enhanced layer list, swipe/spotlight, draw and
print.
Third party ArcGIS Viewer for flex widgets are available for download in the
gallery on the Esri ArcGIS Viewer for Flex resource page:
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http://resources.arcgis.com/en/communities/flex-viewer/. The gallery allows browsing
and downloading of widgets created by the developer community. To add a third party
widget to the application builder interface, make sure the versions match (Flex
application version and widget version), and download the zip file that contains
application builder integration.
For the test application two third party widgets were added: The Enhanced Layer
List widget and the Swipe Spotlight Widget (Figure 3-9). The Enhanced layer list widget
is a table of contents widget that displays and organizes ArcGIS for Server services and
the Swipe Spotlight Widget swipes between operational layers and the basemap below.
Layout
The layout tab allows for configuration of the map elements that are displayed on
the map. Most elements can be toggled on or off and some can be configured further
with the included edit button. Figure 3-10 shows the Layout tab of the application
builder.
Layout elements include:
Directions - Driving directions.
Navigation - Pan and zoom around the map.
Static Image - Displays an image on the map.
Scale Bar - Display a scale bar in your choice of units
Coordinates - Display map coordinates while panning and zooming.
Initial Splash Screen - An info window that greets users upon site opening.
Attribution - Display Esri logo.
Overview Map - Displays a slide out Overview Map.
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Map Switcher - Display that allows switching basemaps and access to included
services.
Search - Allows address geocoding.
Links - Ability to add external links.
Attribute Table - Provides an interface for viewing the attribute table of map data.
For the test application, Directions, Static Image, Attribute Table, and Attribution were
turned off. Some additional configuration was done to the Initial Splash Screen, the Map
Switcher, and Links. In the Initial Splash Screen edit window, some HTML was added
to share information about the site with users. All the HTML code needed was already
provided (Figure 3-11). The image on the splash screen was replaced with a new image
and the text associated with the link was changed by modifying the text (ArcGIS Viewer
for Flex) to (LUCIS Pdf) as seen in Figure 3-12. The edited Splash Content for the test
application can be seen in Figure 3-13.
In the Map Switcher edit window (Figure 3-14) the layer list was turned off as the
third party widget added earlier will perform the function of giving access to operational
layers. Finally, the Links edit window was set up to display the same information that is
available in the Initial Splash Screen.
Design
The Design page (Figure 3-15) has 3 tabs and a preview window. The preview
window shows the viewer application and updates as edits are made.
Logo. The viewer displays an image logo (png, jpg, gif) in the upper left hand
corner of the site. This tab allows for the changing of the default logo (blue world cube).
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Drag a new image into the image drop area or browse to the file to change the image
logo. For the test application the default logo was left unchanged.
Title and fonts. This tab allows changing of the viewer title and the ability to add
a subtitle. Drop downs give the ability to change the fonts used throughout the viewer
application. Selections include title font, subtitle font, and text font.
Color scheme. Set the color scheme of the viewer application. Choose from a
number of predefined styles or build your own. Some elements of the viewer are built to
be transparent. The level of this transparency can be set here as well.
Preview
The preview page (Figure 3-16) shows an interactive preview of the viewer
application in its current state. Any visual changes or manual panning and zooming on
this page will not be saved and will not affect the application in any way. This page is
used to test the viewer elements and decide if anything needs to be added, removed, or
altered. Click the done button to save the completed work and exit the application
builder. All projects are listed on the My Applications page and can be returned to by
clicking the edit pencil in the Actions column associated with the application name.
Using the Viewer Application
After completing the viewer application, it became accessible on the web using
any modern web browser. Project data and analysis results were included in the
application and can be shared easily with both clients and the public. Figure 3-17 shows
the completed viewer application. The Hillsborough County boundary and interstates
are turned on by default in the basemap layers group in the Layer List widget. These
layers are turned on to help define the study area and give a sense of location within the
study area.
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Figure 3-18 shows the fully expanded layer list widget. The bottom right corner of
all widgets can be used to resize the window view. The Layer List widget shown here
has been expanded to show the full layer names. Layers in the sample viewer
application have been set to draw with a slight transparency so the underlying imagery
can be seen. The initial transparency can be adjusted in the Maps section of the
application builder as described earlier and in the viewer application by clicking the drop
down arrow of a parent group and choosing transparency.
The basemap can be changed using the basemap widget shown in Figure 3-19.
Figure 3-20 shows the test application displaying imagery with place labels added.
Switching to this basemap is accomplished using the Basemap widget shown in Figure
3-19. Simply hover over the basemap icon and the basemap options will expand. The
basemaps shown here were set from the basemaps tab on the Basemaps &
Operational Layers page that was discussed earlier in the methodology section.
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CHAPTER 4DISCUSSION
The accessibility and dissemination of tools like the ArcGIS Viewer for Flex in the
planning profession can have tremendous positive effects on collaboration and the
ability to communicate both quantitative and qualitative information about spatial
analysis. Collaboration through web GIS avoids the problems with data transfer and file
formats. Data is accessible faster and requires less work from collaborators viewing the
results. This project has focused on the ArcGIS Viewer for Flex and its ability to
accomplish these goals. Using the tools provided with the ArcGIS Viewer for Flex a fully
interactive web map was created without any software development knowledge. The
process of creating the live test application was simple enough that researchers and
planners can share spatial data with very little technical knowledge.
The test application created for this project provides collaborative benefits that
are both qualitative than quantitative. Take for example Figure 21 and Figure 22.
The value of the ArcGIS Viewer for Flex as a platform is immediately apparent when
comparing data in the map viewer. Qualitative comparisons are a major strength of the
platform. Take for example the surfaces that show infill industrial development (Figure
21) and greenfield development for commercial, retail, service and institutional uses
(Figure 22). It is very easy to ascertain that there is more land suitable for greenfield
development than there is for infill industrial development. This is one of the simplest
benefits of the software, but also one of the most powerful. With the ability to overlay
many data layers together, relationships and associations can be made that may never
have been realized on their own. Visually you can answer many questions quickly and
easily.
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Viewing the suitability surfaces, quantitative comparisons can be made as to how
suitable project areas are for specific land uses. These surfaces were created using the
LUCIS model which gives measurable scores for suitability. Figure 23 shows high
suitability (green) vs. low suitability (red) areas for institutional uses.
With the data used in this project, there are fewer quantitative comparisons to
make because of the nature of raster data. It is not possible to simply get an acreage
number for both development types and compare them from within the viewer. This kind
of quantitative comparison is possible when using vector data and the ArcGIS Viewer
for Flex provides identification tools to accomplish these kinds of comparisons. It’s
important to note that this is not a limitation of the ArcGIS Viewer for Flex platform, but
of the data used in this particular project.
The important thing to note with the above comparison is the ease with which it is
accessed and its availability online. The test application can be accessed through any
modern internet browser. The data and the interactive environment that the ArcGIS
Viewer for Flex provides is an always on resource discoverable on the web.
In Figure 24 the map clearly shows the areas that the LUCIS analysis has
allocated as industrial land use on top of the industrial suitability surface. The
Swipe/Spotlight widget was used to swipe over allocations and examine the suitability
below. By switching focus layers it is possible to swipe between all layers included in
the map. Turning on multiple suitability surfaces shows what locations are highly
suitable for more than one use. The draw widget was used to highlight areas of the map
on the fly and print results for sharing. Relevant data can be added and removed to
better see the story your analysis is telling. Do the allocations look correct? Why aren’t
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the target areas suitable? Why are competing parcels more suitable? Many of these
questions require consensus building, multi-organization collaboration, and public input.
Often all of these things happen at great distances from each other. The ArcGIS
Viewer for Flex application is a powerful tool to expand the reach and explanatory
power of data and analysis. Tools like these are not out of reach for the non-web
developer crowd. The test application discussed in this paper used as many default
options as possible and only a small sampling of the available widgets. With a little time
and experience everything produced here can be expanded and modified to
accommodate any project or research.
Although the ArcGIS Viewer for Flex has many benefits, there are also a number
of limitations that newer technologies are handling in much better ways. The biggest
limitation is the need for a server. Many planners simply don’t have access to their own
personal server machines. Those that do may not have the expertise to optimally
configure them and maintain them. Specialized system administrators are often needed
to handle installations, manage day to day server health, and address down time when
problems arise.
A concern of all internet applications is the size of data and the speed at which it
can be delivered. Very large data can degrade the performance of the ArcGIS Viewer
for Flex. Although it is a robust platform, very high resolution imagery or intense
datasets such as statewide parcels can cause slow performance leading to long loading
times and even site crashes. This type of problem is common with all web GIS platforms
and can be alleviated with more powerful servers, faster networks, and good data prep
and compression.
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The ArcGIS online options have come a long way in recent years to address
many of these problems. The ArcGIS Online platform has provided updates much more
rapidly compared to the ArcGIS Viewer for Flex, and with each iteration ArcGIS online
adds more customization options. What once was a very rigid and non-interactive
interface has become very customizable allowing for even more symbology options than
are available with the ArcGIS Viewer for Flex. ArcGIS online’s new smart mapping
options allow for easy analyzing and mapping of related data and streamlining of the
user experience.
At this time however, ArcGIS online still does not allow the hosting of raster data.
This is a major drawback and would affect this project in particular greatly. Much of the
data used to create the test application for this project was raster data. ArcGIS online
does provide some work arounds for working with raster data. Raster data can be
cached and published to ArcGIS online as tiles, however this can be costly if the
caching is done using ArcGIS online and also increases data creation time and leads to
additional storage costs. In this case the data management is still much simpler using
the ArcGIS Viewer for Flex.
Many modern web mapping platforms allow for maps to be embedded in other
websites. The ArcGIS Viewer for Flex does not have this functionality, which is another
drawback of the Flex platform. The website would have to be built around the ArcGIS
Viewer for Flex interface and would involve coding that most planners would not have
the knowledge to accomplish.
ArcGIS online has also recently released the Web AppBuilder for ArcGIS which
is a very competent competitor to the ArcGIS Viewer for Flex allowing users to build
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powerful web apps with no coding necessary. Web AppBuilder also has the added
bonus of being able to run on any device because it is based on JavaScript. The ArcGIS
Viewer for Flex’s dependence on flash restricts its use to web browsers on desktops
and laptops as most modern tablets and phones do not run flash. Adobe’s flash is still
widely used on the internet but is slowly becoming obsolete. Boulos (2010) notes:
HTML5 is being developed as the next major revision of HTML (Hypertext Markup Language), the core markup language of the World Wide Web. It aims at reducing the need for proprietary, plug-in-based rich Internet application (RIA) technologies such as Adobe Flash (p. 1).
As many developers move to HTML5 the development of the ArcGIS Viewer for Flex
has slowed. In the future ArcGIS online seems to be a much more suitable platform for
data sharing on the web for planners. It is very likely that future data sharing research
will focus on platforms such as ArcGIS online.
To close, this project has shown the ArcGIS Viewer for Flex to be a very suitable
option for data sharing and collaboration, but that technology and web mapping
platforms are rapidly evolving. Development languages and web standards are
changing constantly. This is great for both planners and the general public as with each
new generation of web mapping platforms more tools are made available with even less
programming knowledge being required. The sharing of ideas and research methods
through the web will continue to grow and foster positive outcomes as long as this
innovation continues.
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CHAPTER 5CONCLUSION
Technology on the web is constantly changing. As current platforms mature and
new platforms are created, data sharing will also change. The ArcGIS Viewer for Flex is
a very capable stand-alone product and this test case has demonstrated its suitability as
a data sharing platform for the non-programmer. However, the future of web GIS and
data sharing will be found in alternative platforms for two main reasons. The first is the
ArcGIS Viewer for Flex’s underlying programming dependency on Flash and the need
for users to host their own web services. Flash is going out of style and is not supported
on all platforms, specifically mobile devices. Modern web GIS platforms are pushing
HTML5 and JavaScript more and are often being built specifically with mobile
applications in mind (Boulos, 2010, p. 1). Services although still very popular on
personal servers are moving towards cloud based solutions. A good example of both of
these trends coming together is ArcGIS Online which is JavaScript based and allows for
data to be uploaded to the cloud and hosted on Esri’s servers.
Future research on data sharing will focus on cloud based web GIS platforms like
ArcGIS online. They have the benefit of being able to share data hosted on external
servers or data uploaded directly to the cloud. Web based solutions differ from the
ArcGIS Viewer for Flex in that initial set up and customization of your application
happens through a web interface rather than an application that lives on your desktop. It
seems like a very natural progression that this functionality moves to the web. Not only
is the data sharing application online, but so are the tools to create it. Web based
solutions still have their limitations which have been addressed in other parts of this
project, but developers seem to be focused on solving those limitations more than those
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that are found in the ArcGIS Viewer for Flex. As more functionality is brought to these
web based GIS sharing platforms they will quickly become the most widely adopted
solutions for data sharing on the web.
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BIOGRAPHICAL SKETCH
Danny Downing is currently a geospatial analyst and web specialist at the
University of Florida GeoPlan Center. He received his B.S. in Liberal Studies with a
Minor in Biology from the University of Central Florida in 2000. In August 2016 he will
graduate from the University of Florida with a Master of Arts in Urban and Regional
Planning. During his time working at the GeoPlan Center he has contributed to
numerous research projects including Efficient Transportation Decision Making (ETDM),
the Florida Geographic Data Library (FGDL), the Florida Sea Level Scenario Sketch
Planning Tool, and the State Broadband Initiative Program.
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