Lec_12_Intro to Geodatabase and Topology
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Transcript of Lec_12_Intro to Geodatabase and Topology
Introduction to Geo-database and Topology
Prof. Dr. Sajid Rashid Ahmad
Atiqa Ijaz Khan _ Demonstrator
Geo-Database
• “A database or file structure used primarily to store, query, and manipulate spatialdata. Geo-databases store geometry, spatial reference system, attributes, andbehavioral rules for data.”
• A geo-database contains datasets represents collections of information with a realworld interpretation.
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History
• In the beginning, there is NO link between Spatial and Non-spatial data.
• 1st Generation:
• Then, both get linked, but stored in separate files.
• 2nd Generation:
• Finally, the spatial and non-spatial datasets are stored in Same table/folder.
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Geo-Database In ArcGIS
• An ArcGIS geo-database is a collection of geographic datasets of varioustypes held in a common file system folder.
• It is a native data structure, used to edit and manage the data.
• It maintain the integrity of the spatial data.
• It store comprehensive information related with each other through objects,feature classes, feature datasets, etc.
• It is a container used to store information.
• It has easy access and management options.
• Users can apply sophisticated rules and operations to data through it.
• It supports multi-user editing.
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Why to Use it: Benefits
• It is more robust (strong) and extendable than shapefile.
• It make use full capabilities of ArcGIS.
• Support multi-user editing.
• Faster and efficient.
• Manage large datasets easily.
• Use to edit topology.
• Non-spatial data is stored in standard format. Like DBMS (DataBaseManagement System)
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Types of Geo-Database
• There are 2 major types:
• Single-user Geo-database:
• Personal
• File
• Multi-user Geo-database:
• Enterprise
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Geo-Database
Single user
File
Personal
Multi-user
Enterprise
Monday, March 30, 2015Institute of Geology, University of the Punjab
10Key Properties Personal File
Description Original data format for
ArcGIS geo-databases
stored and managed in
Microsoft Access data files
A collection of various types
of GIS datasets held in a
file system folder
Number of Users Single user and small
workgroups with smaller
datasets
Single user and small
workgroups:
Storage Capacity 1TB-256TB 2GB
Supported Platforms Supported by Widows Supported by Cross-
platforms
Security Operating Windows
Data Type Supported by Geo-database
• The data types supported by geo-database are:
• Shapefile
• Computer Aided Drafting (CAD)
• Triangular Irregular Networks (TIN)
• Grids
• Imagery
• Attribute tables
• Raster Data
• Grids
• GPS coordinates
• Survey measurements, etc.
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Fundamental Datasets in Geo-database
• There are 3 major types of datasets, that are supported by Arc Geo-database:
• Feature Class
• Raster Datasets
• Tables
• These are said to be the structure of geo-database.
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1. Feature is an instant of a feature class.2. It is Spatial Object.3. Use to organize theme related feature class.
Feature Class
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1. It contains objects having same spatial references.2. It is a collection a feature class.
Feature Data-sets
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Topology
• “A branch of mathematics that deals with the properties of a figure that remainsunchanged ever when the figure is bent, stretched, or otherwise distorted.”
• “In geo-databases, topology is the arrangement that defines how point, line, andpolygon features share coincident geometry.”
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Types of Topology
Topology
Map Topology
Geo-database Topology
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Map Topology
• “A temporary set of topological relationships between coincident parts simplefeatures on a map, used to edit shared parts of multiple features.”
• Allows user to edit on scree, by adjusting edges (lines), nodes (end points oflines), etc.
• Can be applied to shapefile and feature class.
• It does not use topology rules.
• Provides with limited version of topology.
• Available at Topology toolbar.
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Geo-database Topology
• “Geo-database topology defines the spatial relationships of data that all featureclasses must be in the same feature datasets”
• It can only be created for vectors, not for raster.
• It stores errors, exceptions etc.
• It has more extensive rules of topology.
• It can manage and fix the topological errors.
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Topological Convention
• A topology can reference one or more feature classes from the same featuredataset.
• A feature dataset can have more than one topology.
• However, a feature class can only belong to one topology.
• A feature class cannot belong to a topology and a geometric network.
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Topology Rules
• “A group of instruction to the geo-database defining the permissible relationshipsof features within a given feature class or between features in two different featureclasses.”
• Different types of rules are available for different types of spatial relationships.
• Some rules are for within a feature class.
• Some rules are for between two feature classes.
• There are 26 rules available in ArcGIS Topology, having 3 divisions:
• Polygon Rules
• Line Rules
• Point Rules
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Download the Rules Poster: Link
http://www.google.com.pk/imgres?imgurl=https://apollomapping.com/wp-content/user_uploads/2014/05/topology_rules_poster-
300x234.jpg&imgrefurl=https://apollomapping.com/blog/g-faq-spatial-topology-gis-part&h=234&w=300&tbnid=whDwfYDh4DhTtM:&zoom=1&docid=Lak_ZoGKneoPr
M&ei=7Z8VVdyCFI3uatHbgqgO&tbm=isch&ved=0CCYQMygNMA0
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