slide1
Download
Skip this Video
Download Presentation
Geodatabases in GIS Engineering Geographic Information Systems CIVE 7397 Spring 09

Loading in 2 Seconds...

play fullscreen
1 / 22

Geodatabases in GIS Engineering Geographic Information Systems CIVE 7397 Spring 09 - PowerPoint PPT Presentation


  • 86 Views
  • Uploaded on

Geodatabases in GIS Engineering Geographic Information Systems CIVE 7397 Spring 09. Introduction. In ArcGIS, there are three basic data structures: shapefiles, coverages, and geodatabases.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Geodatabases in GIS Engineering Geographic Information Systems CIVE 7397 Spring 09 ' - griffith-torres


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2

Introduction

In ArcGIS, there are three basic data structures:

shapefiles, coverages, and geodatabases

slide3
A geographicdata modelis a structure for organizing geospatial data so that it can be easily stored and retrieved.

Data Models

Geographic coordinates

Tabular attributes

slide4
Coverages

Developed for workstation Arc/Info ~ 1980

Complex structure, proprietary format

Attributes in Info tables

Shapefiles

Developed for ArcView ~ 1993

Simpler structure in public domain

Attributes in dBase (.dbf) tables

File-based Data Models

Geographic coordinates and attributes

are stored in separate but linked files

Arc

Info

slide5

Storing Data

Texas

Texas

Counties

Counties.shp

Counties.shx

Counties.dbf

Evap

Evap.shp

Evap.shx

Evap.dbf

Info

Coverages

Shapefiles

slide6
Coverages and Shapefiles

Coverages are stored partially in their own folder and partially in the common INFO folder. Shapefiles are stored in three to five files (with extensions .shp, .shx, .dbf, .sbx and .sbn)

Coverages store common boundaries between polygons only once, to avoid redundancy. Shapefiles store all the geometry of each polygon regardless of redundancy

Coverage features are single lines or single polygons. Shapefiles allow features to have multiple, disconnected, intersecting and overlapping components

Storing Data - Cont’d

slide7

Geodatabase and Feature Dataset

  • Ageodatabaseis a relational database that stores geographic information
  • It is a data storage and management framework for storing and manipulating spatial, geographic and attribute information
slide8

Geodatabase Structure

  • Feature class: Contains geographic information of geometric type (points, polygons, and lines) and spatial reference
  • Feature datasets: A group of feature classes forms a feature dataset
  • Non spatial tables: These do not contain any spatial attributes but can be connected to tables that have spatial information

Source: ESRI

slide9

ArcGIS Geodatabase

Workspace

Geodatabase

Feature Dataset

Feature Class

Geometric

Network

Relationship

Object Class

slide10

Why the Geodatabase

  • Geodatabases can be used to manage raster datasets
  • Scalability: Can create a personal geodatabase or a geodatabase for the enterprise
  • Attributes can be easily created and maintained
  • Geometric networks can be created for path finding analysis
slide11
Anobject classis a collection of objects in tabular format that have the same behavior and the same attributes.

Object Class

An object class is a table that has a unique identifier (ObjectID)

for each record

slide12
Afeature classis a collection of geographic objects in tabular format that have the same behavior and the same attributes

Feature Class

Feature Class = Object class + spatial coordinates

slide13
A relationship is an association or link between two objects in a database

A relationship can exist between spatial objects (features in feature classes), non-spatial objects (objects in object classes), or between spatial and non-spatial objects

Relationship

slide14

Relationship

Relationship between non-spatial objects

Water

Quality

Data

Water

Quality

Parameters

slide15

Relationship

Relationship between spatial and non-spatial objects

Water quality data

(non-spatial)

Measurement station

(spatial)

slide16

Populating the Geodatabase

  • The following file types can be imported into a geodatabase:

Shapefile, Coverage, Raster, CAD, Feature class

  • The following file types can be exported from a geodatabase:

Shapefile, Coverage, XML, Raster, Feature class

slide17

Generating New Data

  • Scanning data: Produces a raster image which can be georeferenced after scanning
  • Digitizing image

Geographic Coordinate

System

Projected Coordinate

System

Coordinate Domains

slide18

Creating a New Feature Class

  • Need to define geometry type (line, point etc), spatial reference, fields in the attribute table
slide19

Feature Class Properties

  • Need to define geometry type (line, point etc), spatial reference, fields in the attribute table
slide20

Validating the Geodatabase

  • Defining Subtypes and Domains
    • Subtype: Subset of a record within a field
    • Domain: Coded value or range domain

Streets

Pipe

Feature class

Local

Concrete

Steel

Highway

Subtypes

BLVD, RD, AVE

HWY,

FWY

Diameter

> 14 Inch

Diameter

10 – 14 Inch

Domains

slide21

Topology

  • Define spatial relationships between features

--- Connectivity, Adjacency, Coincidence

--- Between one or more features

  • Maintains spatial integrity by setting rules for overlapping, intersecting etc

Examples:

Connectivity: Streams, streets

Adjacency: Land parcels, municipal districts

Coincidence: Boundary

slide22

Examples of Geodatabases

City of Houston needs to design a geodatabase for transportation infrastructure development and construction of a new Metro rail.

What layers/files/tables would the geodatabase contain?

  • Highways
  • Major roads
  • Rail routes
  • Traffic Zone Analysis
  • Traffic Hot spots
  • Congested routes
  • Commute time
ad