GIS Tutorial 1

Lecture 4Geodatabases

With support from:

NSF DUE-0903270

Prepared by:

in partnership with:

David Webb

Geospatial Technician Education Through Virginia’s Community Colleges (GTEVCC)

GEODATABASESLecture 4

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The Geodatabase Poster

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Geodatabase

No more lost data!

Model of reality.

Contains the information needed to

create a map and answer a problem.

Schema already available.

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Geodatabase typesManages features and tables inside a database management system

File geodatabase stores datasets in a folder of files each dataset a file up to 1 TB in size can be used across platforms can be compressed and encrypted for

read-only, secure use ESRI’s recommended choice

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Geodatabase types

Personal geodatabase stores datasets in a Microsoft Access .mdb file storage sizes between 250 and 500 MB limited to 2GB only supported on Windows

ArcSDE geodatabase stores datasets in a number of optional DBMSs:

IBM DB2, IBM Informix , Microsoft SQL Server , Oracle, or PostgreSQL

unlimited size and users

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New file geodatabase

ArcCatalog

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Import into geodatabase

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Shapefile features

Import into geodatabase

Tables

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Export from geodatabase

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Compact geodatabases

File and personal geodatabases Reduces size and improves performance Compact personal geodatabases > 250 MB. Geodatabases with frequent data entry,

deletion, or general editing Open geodatabases in ArcMap cannot be

compacted remove any layers with a source table or

feature class in that database from the TOC

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Compress geodatabases File geodatabases

Once compressed, a feature class or table is read-only and cannot be edited

Compression is ideally suited to mature datasets that do not require further editing

Compressed dataset can be uncompressed to return it to its original, read-write format

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View geodatabases Cannot identify names in Windows

Explorer Must use ArcCatalog

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Geodatabase Essentials

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DATA MODELSLecture 4

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Data Models

Download Models and copy appropriate

portions into your geodatabase.

http://support.esri.com/en/downloads/datamodel

Base maps: http://resources.arcgis.com/content/local-government/basemaps

GDB Design Forms-Tutorial #3

For large Projects and multiple entities

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Student Models

What data is required to answer the

questions…..Often driven by the

limitations on location.

Where to put a wind turbine in

Roanoke area?

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Wind Turbine

Wind power available

Elevation

Slope

Proximity to airports, roads, rivers,

populations

Ability to see from scenic locations

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DATA TYPES Lecture 4

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Vector data Map features

Points, lines, polygons Shape Files

Feature attributes Every feature has attributes (e.g. name,

area, population) Tabular Data

Shape Name Class Pop2000 State

Point New York City 8,008,278 NY

Point Los Angeles City 3,694,820 CA

Point Chicago City 2,896,016 IL

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Feature class

a collection of geographic features that

share the same geometry type (such as

point, line, or polygon) and the same

attribute fields for a common area. Streets,

well points, parcels, soil types, and census

tracts are examples of feature classes.

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Feature dataset

Use feature datasets to organize

spatially related feature classes into a

common dataset:

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Raster DataStored electronic image or picture taken as an aerial photograph or satellite image

Composed of a rectangular array of square cells, called pixels, with a number in each cell representing the solid color fill of that cell

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Supported_raster_dataset_file_formats/009t0000000q000000

/

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Directly loadable data types

dBase (.dbf) Text with comma (.csv) or tab-

separated values (.txt)

Microsoft Access (.mdb)

Microsoft Excel (.xls)

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Triangular irregular networks (TIN)

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Vector based triangles: useful to create slopes, contour intervals and other elevation data. Cannot be stored in a geodatabase.

Terrain

TIN Based surface based on

measurements stored as features in a

geodatabase.

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TOPOLOGYLecture 4

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Topology

Quality Assurance of Data

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Topology

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Topology tw_651

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