Welcome to Welcome to DEP’s GIS Workshop DEP’s GIS Workshop

SeriesSeries

Workshop 2: GIS Data and File Types

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Explanation of Some GIS Terms

Spatial Data – any data that can be represented as a location on the face of the Earth.

GIS – Geographic Information System - is any system for capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to Earth.

2GIS File Types in DEP

Explanation of Some GIS Terms

Vector Data – Data that contains individual features such as rivers, lakes, roads, soils, aquifer protection areas, dam sites. Also known as feature data.

Raster Data – Data that is just a “picture” and contains no information about individual features. For example, the topo maps are raster data. There is no information about individual features such as rivers, lakes, etc. other than what is viewed in the “picture”. Also known as image data.

3GIS File Types in DEP

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Explanation of Some GIS Terms

Points – That spatial data type that consists only of points, or locations, on a map. An example is dam locations in Connecticut.

Lines – That spatial data type that consists only of lines

on a map. An example is roads.

Polygons – That spatial data type that consists only of areas on a map. An example is DEP state parks parcels.

GIS File Types in DEP

Explanation of Some GIS Terms

Feature Class, Dataset, Datalayer – These are all terms that refer to one “layer” of data on a map. For example, the feature class “Named Waterbodies” contains only waterbodies. The feature class “Soils” contains only soil areas. The feature class “Dams” contains only points on the map where dams are located.

Rasters or images are also considered datalayers. For example, the USGS Topographic Quadrangle Maps is a datalayer.

5GIS File Types in DEP

GIS File TypesCoveragesShapefiles (.shp)Raster or Image Data (.tif, .sid, .jpg, .bmp,

etc.)Personal Geodatabases (.mdb – same as

an Access database)File Geodatabases (.gdb)ArcSDE Databases (best accessed through

layer files)

GIS File Types in DEP 6

Coverages

Old formatUsed in ArcView 3 and earlier versionsNo longer editable in ArcGIS 9.3, but can be

displayedCumbersome File StorageCan include export files (.e00 file extension)

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Coverages

GIS File Types in DEP 8

Export Files

Coverage Files

ShapefilesHas become a worldwide standard for GIS

data

Can be displayed and edited in ArcGIS 9.3 and in all earlier versions of ArcView.

Has multiple files for storage; can be cumbersome. For example, all of these files as viewed in Windows Explorer make up one shapefile: Town.shp, Town.shx, Town.sbx, Town.sbn, Town.prj, Town.dbf

Using the Desktop Administrator and GIS File Types in DEP 9

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Aquifer Protection Area Shapefiles

Using the Desktop Administrator and GIS File Types in DEP

Raster or Image Files

Using the Desktop Administrator and GIS File Types in DEP 11

• Raster Files do not have identifiable

or editable features

• Many types of raster (image) files

can be used in ArcGIS:

.tif, .jpg, .png, .gif, .bmp, .sid, .dwg

Personal GeodatabasesIs an Access Database (.mdb file)

All spatial data and tables reside in one file

Easy storage format

Topology can be used for spatial accuracy

Can contain multiple types of data (tables,

feature classes, layers, rasters, etc.)

Maximum file size: 2 gb

Using the Desktop Administrator and GIS File Types in DEP 12

File Geodatabases

Data stored in a folder with an extension of “.gdb”.

Contains a number of filesIs meant for large amounts of dataIs very fast at data retrievalIs more efficient than a personal geodatabaseIs a new file type, not yet well known or used.

GIS File Types in DEP 13

ArcSDE DataStands for Spatial Data Engine

Managing spatial data and relational

databases with large amounts of data

Is the future of GIS data in DEP

Most efficient for large organizations

Can support multi-user editing

Works with SQL, Oracle

GIS File Types in DEP 14

Example of ArcSDE Files

15GIS File Types in DEP

What are Layer Files?Characterized by “.lyr”.

Does not contain actual spatial or attribute

data, only “points to” data

Determines symbology, scale levels, table

view, data view

Can have multiple datasets in one layer

Easy to use – just add one .lyr file

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Example of Layer Files

17GIS File Types in DEP

What is the R: Drive?

Central repository for all GIS data

Contains all file types that exist for a datalayer

Will soon be replaced by a different GIS storage area on the Y: Drive

GIS File Types in DEP 18

Chart of R: Drive FilesVs. ArcSDE Files

Navigate to C:\ArcGIS_Training\Class2\

Open the following file:Rdrive_and_SDE_Layers.pdf

This is a list of the old R: drive files and their corresponding files in SDE

GIS File Types in DEP 19

Class Exercise

GIS File Types in DEP 20

1. Open ArcCatalog2. Navigate to the following folder:

\My Documents\Class2\GISFiles\3. What types of GIS files do you see in this folder,

i.e. shapefiles, SDE files, coverages, layer files, file/personal geodatabases, etc.?

4. ____________________________________5. ____________________________________6. ____________________________________7. ____________________________________

Class Exercise - Answers

GIS File Types in DEP 21

1. File geodatabase “Habitat.gdb”2. Personal geodatabase “Statewide_Trails.mdb”3. Layer file “Connecticut_Town.lyr”4. Shapefile “Dam.shp”

End of Workshop 2End of Workshop 2

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