GISC 6382 Applied GIS UT-Dallas Briggs

GISC 6382 Applied GIS UT-Dallas Briggs
The Geodatabase GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Fundamentals
Spatial data formats Geodatabase data structure Personal vs. enterprise geodatabase Components of geodatabase Building geodatabase GISC 6382 Applied GIS UT-Dallas Briggs

Geographic Feature Data Formats
Formats are based on representations (models) of the real world that can be placed in a GIS to produce maps, perform interactive queries, and execute analyses. CAD – first computer mapping model/format. Binary file format with little attribute information. Coverage – native ArcInfo 7 format. Based on Georelational data model. Vector data is maintained in indexed binary files and partitioned from, but linked to attribute tables by a common identifier. Topological relationships are maintained. Shortcomings – features aggregated into collections of points, lines & polygons with generic behavior. The behavior of a line representing a road is the same as the behavior of a line representing a stream. GISC 6382 Applied GIS UT-Dallas Briggs

Geographic Feature Data Formats
Shapefile – introduced with ArcView Also georelational data model – nontopological vector data format. Very prolific format – much GIS data in Shapefile format. Simpler than coverage because they do not store topological associations among different features and feature classes. Limited analysis capabilities due to lack of topology Geodatabase – introduced in ArcInfo 8. Object-oriented model – can characterize features more naturally by defining object types, topological, spatial and general relationships, and interactions. Geodatabase features can be stored in a single database. Create custom features in addition to points, lines, polygons Brings physical model closer to logical model. GISC 6382 Applied GIS UT-Dallas Briggs

Supported Data Types ArcInfo 8 supports four representations of geographic data. Vector data for representing features. Raster data for images, grids, and surfaces. Triangulated irregular networks (TINS) for surfaces. Tabular data. Locators and addresses for finding a geographic position from an address. Locators apply national postal conventions to convert an address to a position. Note: in AI8.1, geodatabases do NOT store TINS. They must be kept in coverage workspaces. GISC 6382 Applied GIS UT-Dallas Briggs

What is a Geodatabase? A new type of geographic data format (GDF) for ArcInfo 8. Based on Object-Oriented Model Users can add behavior, properties, rules and relationships to data Implemented as extension to standard relational database technology Supports topologically integrated feature classes Extends the coverage model with support for complex networks, relationships among feature classes, and other object-oriented features Provides platform for development of custom data models using visual tools like CASE (Computer Aided Software Engineering) tools and UML (Unified Modeling Language) notation GISC 6382 Applied GIS UT-Dallas Briggs

ArcCatalog Is the Principal User Interface Used to Define and Manage the Geodatabase GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Framework
ArcCatalog ArcMap GISC 6382 Applied GIS UT-Dallas Briggs

Personal (single-user) Geodatabase
Personal Geodatabase. Implemented as a Microsoft Access database (*.mdb file) by using MS jet engine which is installed with AI8. MS access is not needed. Can be placed on local or network drives. Generally used for personal or small work-group use. Can handle small to moderately sized datasets. Personal geodatabase can yield decent performance for datasets of 250,000 objects or less, maximum size is 2.0 GB Full functionality of geodatabase served through ArcSDE except versioning. Versioning – allows many editors to work concurrently and includes framework to resolve edit conflicts. If a personal geodatabase is deleted its gone. GISC 6382 Applied GIS UT-Dallas Briggs

Enterprise (Multi-user) Geodatabase
ArcSDE Geodatabase ArcSDE is the multi-user data access extension to ArcInfo (bundled w/software) that serves geodatabases to AI applications running on pc’s on TCP/IP network. Used for demanding datasets requiring concurrent editing by multiple users. Created by installing a DBMS and ArcSDE on a server. ArcCatalog only creates and deletes connections to ArcSDE geodatabases. Can be deployed on UNIX or Windows NT. Many use UNIX platform for ArcSDE and DBMS and NT for AI applications ArcSDE is centrally tuned and managed by a DBA. Can build SQL applications to access tables in a remote geodatabase. GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Elements Objects & Object classes Features & Feature classes Feature datasets Spatial references Domains Subtypes Relationships & Relationship classes Geometric networks Labels and Annotation GISC 6382 Applied GIS UT-Dallas Briggs

Objects & Object Classes
Geodatabases organize geographic data into a hierarchy of data objects. Objects are instances of an object class that have properties and behavior. Objects can be related to other objects via relationships Objects have unique system identifiers (OID) Object classes are tables in a geodatabase storing non-spatial data (e.g., Parcel owners) Objects in an object class have the same Properties - stored in the table as attributes Behavior - implemented as a component GISC 6382 Applied GIS UT-Dallas Briggs

Object Classes (tables)
Pump Table OID Pump Type Inlet Size ……. 175 Axial Flow 24” … ………… A row stores an Object GISC 6382 Applied GIS UT-Dallas Briggs

Features and Feature Classes
Features are objects with required shape (Points, Multi-points, Lines & Polygons) that represent a real world object in a layer on a map. Features classes are collections of features with same type of feature geometry and attributes. A feature class is also an object class which stores spatial objects (features) (e.g., Parcels). All the features in a feature class are in the same spatial reference. Feature classes which store topological features must be contained within a feature dataset to ensure a common spatial reference. GISC 6382 Applied GIS UT-Dallas Briggs

Feature Classes Feature Class Table Lateral Water Lines OID Shape Type ……. 583 X,Y,Z,M (BLOB) Domestic … ………… A row stores feature BLOB: Binary Large Object Block GISC 6382 Applied GIS UT-Dallas Briggs

Feature Datasets Containers for feature classes Shared spatial reference Analogous to a coverage less restrictive May also contain relationship classes geometric networks Annotations GISC 6382 Applied GIS UT-Dallas Briggs

Building a Geodatabase
Design geodatabase Building a geodatabase Designing the geodatabase (Think before your create) Creating a new geodatabase (Name and location only) Defining the geodatabase structure (Schema and data) Entering spatial data (Loading or automation) Define additional properties (Validataion, relationships, networks) Create a new geodatabase Defining GDB structure Geodatabase Entering spatial data Define additional properties GISC 6382 Applied GIS UT-Dallas Briggs

Designing a Geodatabase
Conceptual Plan: Current and future needs Data contents Coordinate system Data validation and modification rules Relationships among objects Custom objects Logical Design Can use CASE tools What needs to store (Not how to store) UML Use Case Microsoft Visio Enterprise Edition Microsoft Visio Enterprise Version GISC 6382 Applied GIS UT-Dallas Briggs

Creating a New Geodatabase
Create a new geodatabase using ArcCatalog Create new Rename default name GISC 6382 Applied GIS UT-Dallas Briggs

Defining Geodatabase Structure
Create from scratch manually. Use tools in ArcCatalog to create schema Importing existing database schema Can convert by importing schema from existing datasets Use CASE tools and UML to automate database creation. Can use CASE tools to create new custom objects and/or generate a geodatabase schema from UML CASE (Computer Aided Software Engineering) UML (Unified Modeling Language) GISC 6382 Applied GIS UT-Dallas Briggs

Create schema from scratch manually
Define structure using ArcCatalog Feature datasets Feature classes Tables Relationship classes What to Define? Database name Field name and properties Spatial reference Table relationship parameters GISC 6382 Applied GIS UT-Dallas Briggs

Importing existing database schema
Import data and/or database schema Shape files, coverage, features class INFO, dBase tables Options while importing Rename object Rename or exclude attribute columns Modify spatial reference Insert feature class into feature dataset GISC 6382 Applied GIS UT-Dallas Briggs

Use CASE tools and UML to define database structure
Physical Design using UML Feature class, relationship class, subtype and/or domain schema Design large database with visualization and documentation of data relationship and attributes Edit ESRI Object Model diagram Create customize objects inherited from ESRI objects (ArcObjects) Export structure to Microsoft Repository, then to ArcCatalog Visual Basic with GIS Applications (Visual Basic + MapObjects), Substitute Computer Techniques GIS Application Software Development (ArcObjects + UML) GISC 6382 Applied GIS UT-Dallas Briggs

Entering Spatial Data Spatial data automation options Analog data: digitizing or scanning Arc/Info formats: importing and loading Other digital data: data conversion Data Mapping Vector geometry types (p. 81) X, Y: Points, multipoints, lines, polygons Z: Optional position in Z (e.g. elevation) M: Optional linear measurement (e.g. milepost) Field mapping (p. 82) Spatial Reference GISC 6382 Applied GIS UT-Dallas Briggs

Importing Vs. Loading Importing Creates new features within a new feature class or geodatabase table. The features class or table cannot exist before importing Database schema is imported at the same time Loading Appends features into an existing feature class. Existing feature class have the same schema with the data sources Simple Data Loader (ArcCatalog) Object Loader Wizard (ArcMap) GISC 6382 Applied GIS UT-Dallas Briggs

Defining additional database properties
Leveraging geodatabase advantages Add validation rules: subtype and domain Define relationships between tables Create topological structure (Geometric network) Create annotation GISC 6382 Applied GIS UT-Dallas Briggs

Spatial Reference Spatial Reference Coordinate system Spatial domain Precision Cautions All feature classes within a feature dataset share the same spatial reference. Once created, the spatial domain for feature dataset/class cannot be changed. Data outside extent of dataset need to be created in a new feature dataset or standalone feature class. GISC 6382 Applied GIS UT-Dallas Briggs

Coordinate system Projection system & parameters Geographic, UTM and State plane Datum, central Meridian, standard parallels, false northing and easting Define Coordinate system for feature dataset/classes Select: a predefined coordinate system Import: from existing geodatabase Create: a new coordinate system Modify: current coordinate system Save: for future use GISC 6382 Applied GIS UT-Dallas Briggs

Spatial Domain Spatial Domain The allowable coordinate range for the geographic coordinates X/Y Domain: MinX, MaxX, MinY, MaxY Z Domain: Min, Max M Domain: GISC 6382 Applied GIS UT-Dallas Briggs

Precision Precision The number of system units per one unit of measure (of distance). Precision determines the resolution of a map (geodatabase) For example: map unit is meter Precision of 1: 1 system unit = 1 meter (resolution) Precision of 1000: 1000 systems units = 1 meter 1 systems unit = meter = 1 millimeter (resolution) E.g. Map unit feet, Precision of 12, Resolution? 12 system units = 1 foot 1 system unit = 1/12 foot = 1 inch (resolution) GISC 6382 Applied GIS UT-Dallas Briggs

Determine Precision Based on Map Resolution
Formula: Resolution = Map unit / precision Precision = Map unit / resolution Determine precision of a new geodatabase Digitizing table resolution is inches, map scales is 1:10,000, map unit is meter Geodatabase resolution = inches * 10,000 = 20 inches 20 inches = 20 /39.37 meters = .508 meter ~ 0.5 meter Precision = 1 meter / 0.5 meter = 2 GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Storage and Precision
Coverage/Shapefile storage: Single floating point precision (6-7 digits) Double floating point precision (13-14 digits) Geodatabase storage As Integer: 4 byte integer Stores 2.14 billion system units max = 2,147,483,648 Coordinate are Multiplied by precision when stored Divided by precision when used Map units (Use) Floating Point (m) Multiply by precision *1000 Divide by precision 123,456/1000 System units (Store) Integer 123,456 GISC 6382 Applied GIS UT-Dallas Briggs

Check Geodatabase Precision with Range
Range in Map Unit (RangeMU) Larger of width or height Width = MaxX –MinX Height= MaxY – MinY Example 1,000,000 – 200,000 = 800,000 (Width)  RangeMU 4,060,000 – 3,750,000 = 310,000 (Height) Range in system unit (RangeSU) RangeSU = RangeMU * Precision RangeSU = 800,000 * 1000 = 800,000,000 < 2.14 billion Is OK to accept 1000 as precision? 2 billion 4 billion 200,000,000 mm x 3,750,000,000 mm y GISC 6382 Applied GIS UT-Dallas Briggs

Re-center Coordinates using shift
Problem: At desire precision, data is outside extent Solution Shift the center of geodatabase space to the center of the data Shift = the difference between the center of your data and GDBCenterMU Formula: Center of geodatabase space in map units (GDBCenterMU) (2,147,483,648/2)/precision = (2,147,483,648/2)/1000=1,073, Center of your data (DataMinX + DataMaxX)/2 and (DataMinY + DataMaxY)/2 Shift ShiftX = (DataMinX + DataMaxX)/2 – GDBCenterMU ShiftY= (DataMinY + DataMaxY)/2 – GDBCenterMU Update (MinX, MinY) with (ShiftX, ShiftY) GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Storage and Shift
The geodatabase will Subtract shift, then multiply coordinate by precision when stored Divide coordinates by precision, then add shift when used Map units (Use) Floating Point 3,000, (m) 2 billion 4 billion 200,000,000 mm x 3,750,000,000 mm y Add shift 1,000, ,000,000 Subtract shift (3,000, – 2,000,000) Multiply by precision 1,000, *1000 Divide by precision 1,000,000,456/1000 System units (Store) Integer 1,000,000,456 GISC 6382 Applied GIS UT-Dallas Briggs

Subtype and Attribute Domain
Rang domain Coded value domain Associating domain with subtype Attribute validation rules Split and merge domain policies GISC 6382 Applied GIS UT-Dallas Briggs

Why Subtypes and Attribute Domains
Data Integrity Prevent illegal attribute assignment to features, tables with out-of-range data values For certain critical field, provide predefined codes as the only valid values Data Efficiency Associate different subset of a feature class with different default values, attribute validation rules Allow efficient choice from a set of valid value descriptions rather than manually input the value itself PowerPoles Streets Wood Steel Primary Secondary 20-30 30-50 ST, RD, AV, BLVD Ln, Cir, Pl GISC 6382 Applied GIS UT-Dallas Briggs

Subtype Subtype Feature class’ “subclasses” that allow you to further distinguish objects without creating new feature classes Logical groups of a subset of records within a feature class based on single column’s values Same subtype has similar attribute values and behaviors Create Subtype Can choose default subtype Require integer values (long/short), user adds descriptions Can have different default values and domains for each field to improve data efficiency GISC 6382 Applied GIS UT-Dallas Briggs

Creating Subtypes 1 Define subtypes using ArcCatalog For feature class or table properties Select column to create subtype Enter subtype code and description Enter default values and domains for each subtype Set default subtype 4 2 3 GISC 6382 Applied GIS UT-Dallas Briggs

Display and Edit Subtypes in ArcMap
Displaying Subtype can have unique classification Subtype descriptions are listed in TOC Symbols can be modified as desired Adding new features Use Editor Target list to add feature with chosen subtype Editing existing features/records Can apply subtype after data entry Subtype fields shows description, not code Changing the subtype updates the default values for other fields GISC 6382 Applied GIS UT-Dallas Briggs

Domain Define a set of legal values for a field’s attributes Range: specifies a valid range of values for a numerical attributes A water pipe must be between 1 and 100 inches wide Coded value: specifies a valid set of values for an attributes. Can apply to any type of attributes Parcels can only have RES or VAC land use values Validation methods Pulldown list of descriptions (coded values) prevents error Validation during edit session prevents range error A geodatabase property Can apply to entire field or individual field subtype Multiple objects in the same database may use the same domain Cannot edit domain referenced by another subtype GISC 6382 Applied GIS UT-Dallas Briggs

Creating Range Domains
Click on existing or blank domain Enter the name and description for the domain Enter the domain prosperities Field type Domain type: Range Minimum value Maximum value Split policy Merge policy 1 2 3 GISC 6382 Applied GIS UT-Dallas Briggs

Creating Coded Value Domains
Click on existing or blank domain Enter the name and description for the domain Enter the domain prosperities Field type Domain type: Coded Values Split policy Merge policy Enter the coded values Code Description 1 2 3 4 GISC 6382 Applied GIS UT-Dallas Briggs

Associating domains to entire fields
Provide validation for records within a specified field Domain must be defined as same field type Diameter_L is float Only float domain appear GISC 6382 Applied GIS UT-Dallas Briggs

Associating domains to subtype
Provide validation for records within subtype Domain must be defined as same field type Subtype field grouped into four codes Each code has its own domain for other attributes GISC 6382 Applied GIS UT-Dallas Briggs

Editing records that have coded value domains
ArcMap only shows valid domain description View codes in table by changing the appearance of the table GISC 6382 Applied GIS UT-Dallas Briggs

Editing records that have range domains
Perform edit in ArcMap Validate selection verifies fields with a range domain Invalid features remain selected Angle has a range domain of GISC 6382 Applied GIS UT-Dallas Briggs

Split Domain policies Split policies on edited feature’s attribute Owner Zoning Value M. Murad R-4 36000 default value geometric ratio duplicate Split Policy Owner Zoning Value M. Murad R-0 24000 12000 GISC 6382 Applied GIS UT-Dallas Briggs

Merge Domain policies Merge policies on edited feature’s attribute District Yield %harvested Glenwood 24000 35 Lakeview 45000 47 Merge Policy default value sum values weighted average District Yield %harvested California 69000 43 GISC 6382 Applied GIS UT-Dallas Briggs

Table Association and Table Join
Attributes about a feature can be stored Feature class table (Feature class) Separate table (Object class) Associate tables with common column (key) values Primary keys: Common field on original table Foreign keys: Common field on destination table Table join Merge two tables together into one table logically or physically (in ArcMap). GISC 6382 Applied GIS UT-Dallas Briggs

Relationship and Relationship Class
Persistent and Dynamic association between objects in the geodatabase Change to origin table can been seen when the destination access the relationship. The relationship exist unless deleted. No merging of two tables Common field with same data type Between non-spatial objects (rows in tables) Between spatial objects (features in feature classes) Between spatial and non-spatial objects Non relationship based on BLOB fields No relationship based on location Relationship class A geodatabase relationship is stored in relationship classes. It is save as a record (row) in a relationship table. GISC 6382 Applied GIS UT-Dallas Briggs

Geodatabase Relationship
Characteristics of relationship Persisted relationship in the geodatabase Can enforce dependent behavior Can edit, query, and symbolized across relationship Can only relate tables within the same geodatabase Do not support access to stacked relationships If A  B, BC; then A can not access C unless AC Origin Destination GISC 6382 Applied GIS UT-Dallas Briggs

Creating Relationship Classes
Relationship properties Relationship name Origin and destination tables Relationship type Simple or composite From-to, to-from labels Messaging direction Cardinality (1-1, 1-M, M-N) Foreign key, primary key GISC 6382 Applied GIS UT-Dallas Briggs

Table Relationship Cardinality
Defines how many A objects are related to B objects Influence relationship properties and uses 1-1 (one-to-one) 1-M (one-to-many) M-N (many to many) Many parcels have many owners One parcel has one owner One parcel has many owners GISC 6382 Applied GIS UT-Dallas Briggs

Relationship Type Simple Peer-to-peer relationship that are between two or more objects that exist independently of each other Delete origin objects, related objects in destinations table continuous to exist – FK value is deleted Can have one-to-one, one-to-may, or many-to-many cardinality Composite The life time of one object controls the lifetime of its related objects Destination objects cannot exist without origin object Can only have one-to-one, and one-to-many cardinality. GISC 6382 Applied GIS UT-Dallas Briggs

Keys, Path Labels and Messaging Notification
From origin to destination based on common field Primary Key (PK): On origin (Parcels) Foreign Key (FK): On destination (Owners) Path labels Forward (From-to): To navigate the relationship from the origin table to the destination table. (E.g. Is owned by) Backward (To-from): To navigate the relationship from the destination table to the origin table. (E.g. owns) Messaging Notification Direction to propagate standard message between related objects Used to trigger behavior (e.g. cascade move, custom) Origin to destination, destination to origin, both, none GISC 6382 Applied GIS UT-Dallas Briggs

Relationship Rules and Validation
Property set after creating the relationship class Controls which object subtypes from origin class can be related to which object subtypes in destination class Also the valid cardinality range for all permissible subtype pairs. Cardinality (1-1, M-1, M-n) does determine or control the actual quantity (and types) of related records Validate Selection check for attribute violation After validation, all invalid records remain selected GISC 6382 Applied GIS UT-Dallas Briggs

Open Related Table in ArcMap
Add origin table, destination table, or both Table appears in Table of Contents Source tab Open table Use Options > Related Tables GISC 6382 Applied GIS UT-Dallas Briggs

Querying related tables
Query records from first table using Option> Select Attribute… Click Options>Relationship> Path Label name to refresh related table Selected records highlighted in related table, regardless of messaging GISC 6382 Applied GIS UT-Dallas Briggs

Symbolizing and labeling with related fields
Properties Fields tabRelated Fields GISC 6382 Applied GIS UT-Dallas Briggs

Displaying and editing related records
Classification based related fields appears in the Table of contents Fields in related table appear in Attribute dialog GISC 6382 Applied GIS UT-Dallas Briggs

Reading MacDonald, Chapter 1, 3, 4, 5 Zeiler, Chapter 1-5 GISC 6382 Applied GIS UT-Dallas Briggs

GISC 6382 Applied GIS UT-Dallas Briggs

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