GEOStore: “New web marketing and distribution

techniques for geolocated digital content”

V. Sanjaime, A. del Rey (1), L. Vicens, R. Olivella, A. Hernández (2), G. Beltrán (3)

(1) PRODEVELOP, S.L Pza. D. Juan de Villarrasa, 14, entlo pta. 5 46001 Valencia, ibrodin@prodevelop.es.

(2) SIGTE, Facultat de Lletres, Universitat de Girona, Pl. Ferrater Mora, 1 17071 Girona, info@sigte.udg.edu

(3) GEOTURISMO, Calle Archiduque Carlos, 6 pta 17 Valencia, gerson.beltran@gmail.com

GEOStore: “New web marketing and distribution

techniques for geolocated digital content”

ABSTRACT

There are several problems in both performance and usability in the representation and

provision of large volumes of geospatial data on the web.

In reference to usability, users often encounter cases such as simultaneous display of a

great deal of data that are stacked on the same geographical area, which makes it

difficult to differentiate them and see the map underneath.

In regard to performance, problems are found with the server, i.e., large amounts of

data involve a great number of queries to databases and large volume of memory used

per request; in reference to bandwidth, great amounts of data travelling over the internet

involves delays in requests and high bandwidth consumption. As for clients, the

problems have to do with the fact that current web browsers have trouble rendering

large amounts of data.

This article shows improvements in these areas via level of detail techniques and

clustering and generation and precaching of tiles with vector data in a similar manner to

what is done with the information in raster format. Likewise, ETL (Extract-Transform-

Load) techniques are shown with those obtained from web data from a different source

for integration into a single repository.

Keys word: geolocated digital contents, clustering, vector usability, ETL,

interoperability.

1. INTRODUCTION

The main technological objective of the GEOStore project is industrial investigation

into new types of geolocated digital content such as 3D models and augmented reality

and defining new bundling techniques and web distribution of these digital contents to

facilitate new business models.

To achieve this goal, secondary objectives are also being addressed to maximize

interoperability with existing and future platforms, as are improvements in performance

and usability over current processes that enable working with large volumes of data on

the web and on mobile devices.

It is anticipated, when the project is completed, that the results can be used to enhance

technological development in growth sectors within the scopes of various digital

contents in sectors such as education, geomarketing and urban management, among

others, and especially tourism.

Moreover, these results can be applied in all sectors that enhance development of

geolocated digital content in the information society, in that the processes obtained will

facilitate the creation of platforms and interoperability between them for the

distribution of digital content, their marketing and sharing via social networks. The use

of these techniques will strategically position the sectors applying them in the Web 2.0

market.

This article shows the results obtained thus far in terms of integration of existing

geospatial data sources and vector performance and usability on the web.

2. INTEGRATION OF EXISTING GEOSPATIAL DATA SOURCES

Based on identification of those data sources relevant to the project and their

characterisation in terms of type of license and accessibility, the implementation of a

demonstrator built on the ETL tool (“Extraction, Transform and Load”), GeoKettle,

(http://www.spatialytics.org/projects/geokettle) has been undertaken for the importation

and integration of geolocated data into a single spatial database: PostGIS

(http://postgis.refractions.net), which will be the central GEOStore repository.

To implement this demonstrator, three basic and generic sources of widely used and

followed information such as Wikipedia, Flickr and OpenStreetMap were selected. In

all cases, a crowdsourcing type of information was used, in which it is the users

themselves who voluntarily maintain and add new information to the network.

The three sources of information shared a common feature: the information that can be

queried and, ultimately, downloaded is likely to be located at a specific spot on the

earth's surface or, in other words, it is geolocated information. In contrast, there are

three completely different sources of data or information in regard to the format and

nature of the data they contain (text and graphs in the case of Wikipedia, photographs

for Flickr, and geometry and attribute values in the case of OpenStreetMap).

To overcome this difficulty, a GeoKettle workflow was designed. It was based on the

use of APIs (Flickr), SQL scripts and statements to download information from the

network, edit it and store it in the PostGIS database.

Fig. 1: General workflow (job) defined in Geokettle

The entire process shown in the figure above is run simultaneously: thus we obtain the

information we wish to store in Wikipedia, Flickr and OpenStreetMap.

Downloading data from OpenStreetMap and Wikipedia was carried out directly from

the network. Once downloaded, they were processed in GeoKettle before being

imported to the central database using the various connectors to databases (MySQL and

PostgreSQL).

Fig.2. Workflow for download of georeferenced articles from Wikipedia

Fig.3. Workflow for download of georeferenced articles from OpenStreetMap

In the case of Flickr, its API was used (http://www.flickr.com/services/api/) in REST

format (http://en.wikipedia.org/wiki/Representational_state_transfer) for geolocated

data download. Flickr limits the maximum download of elements per request to prevent

massive downloads. For this reason, it was necessary to automate the generation of

requests (in URL formats) to invoke the API without exceeding the download

maximum. The automation process was rendered by defining a recursive script in

python. After downloading the data in XML format, it was parsed and imported to the

central database from GeoKettle.

Fig.4. Work flow for downloading georeferenced data from Flickr

3. VECTOR PERFORMANCE AND USABILITY IN THE WEB

A state of the art for OGC/ISO standards has been rendered for access to vector data,

which reflects the main techniques and standard format and storage protocol systems

and transmission vector GIS information as well as its capabilities in regard to

representative (3D support, augmented reality, etc.) and functional capacity (editing,

transactions, payment details, etc.).

Moreover, various research activities have been conducted to achieve an increase in

reading capacity of vector data using and improving OGC standards and the study of

the existence and use of APIs in open source software based on OSM to download and

create points of interest from the Internet for web clients and mobile platforms

(“Wikipedia sites”).

In reference to research techniques for improving performance and usability of web and

mobile customers, a line of research has been opened for creating components based on

multilevel visualization techniques and space partitioning techniques via:

• Geographic tiling

• Grouping based on levels of detail

Tiling allows splitting geographic information based on its location into a hierarchical

tree shaped structure. The hierarchical structure levels refer to the visualization levels

defined in the display. Each level has a spatial segregation that quadruples that of the

highest level. This model is well established in web servers that offer raster cartography

via WMS-C, TMS and other protocols. In this case, attributes and vector element

geometry of the layer of information points are stored in each tile of each level.

Fig. 5. Distribution of geographic elements in the tile structure by level of visualization

Furthermore, grouping of information by levels of detail makes it possible to

agglutinate nearby isolated information; thus, the number of elements represented on

the map at a zoom level is reduced, thereby increasing the legibility of the map since it

is not saturated with information.

Fig. 6. Synthesis model of geographic elements by level of visualization

This model combines tiling of information by levels and the clustering of information

makes it possible to provide the tiles with vector information that the web browser will

specify sequentially through small GeoJSON format files that have information from a

defined geographical area.

The components created enable an increase in performance and usability when

displaying and interacting with information thereby solving the problem browsers have

when painting large amount of these elements.

Fig. 7. Combined tiling and clustering model of geographic information

ACKNOWLEDGEMENTS

The GEOSTORE project was started in 2011 and has been developed over the past two

years by the Prodevelop S.L. and Geoturismo S.L. companies and the Servicio de SIG y

Teledetección of the Universidad de Girona with funding from the Plan Avanza (Digital

Content) from the Spanish Ministry of Industry, Tourism and Commerce.

Fig. 8: Project logo and of entities that have funded it

Work is currently being done to show the final project demonstrator: the online

geolocated multimedia products store. The portal was developed using Drupal 7 and the

e-commerce module. The store will be able to store and make available to users a large

quantity of geolocated spatial information. The information is displayed to the user

through listings or on a map, with the aid of its geographical location. In addition, the

store will permit any person or entity to add their geographical elements.

Presently, there is an alpha version that can be queried on the internet at the following

web address: http://geostore.prodevelop.es

Fig. 9: Appearance of the alpha version of the online GEOStore.

FIGURES

- Fig. 1: General workflow (job) defined in Geokettle

- Fig.2. Workflow for download of georeferenced articles from Wikipedia

- Fig.3. Workflow for download of georeferenced articles from OpenStreetMap

- Fig.4. Work flow for downloading georeferenced data from Flickr

- Fig.5. Distribution of geographic elements in the tile structure by level of

visualization

- Fig.6. Synthesis model of geographic elements by level of visualization

- Fig.7. Combined tiling and clustering model of geographic information

- Fig.8: Logo of the project and of entities that have funded it

- Fig.9: Appearance of the alpha version of the online GEOStore.