Introduction to the ArcGIS Data Model and Application Structure

Transcription

1 Introduction to the ArcGIS Data Model and Application Structure RNR/GEOG 417/517 Lab 6 Presentation Overview The georelational data model Structure of ArcGIS software Structure of an ArcGIS workspace Demonstrations/previews Preview of the SVRD data set in ArcMap Demonstration of ArcCatalog, ArcMap, and Editor Demonstration of table editing in ArcMap 1

2 ARC/INFO Data Model A hybrid data model, often referred to as the georelational model, is used to maintain the connection between features and their descriptive data. Georelational and the Geodatabase Geometry ID In the Geodatabase (GDB) Geometry and attribute data are stored in the same relation The geometry is stored as a BLOB to protect it from the user The software creates default attributes for ID and some geometric properties The software allows for user defined attributes in the feature class table, or in related tables User Defined Geometric Properties 2

3 What is ArcGIS ArcGIS for You In the labs you will use the following desktop components: ArcMap ArcCatalog ArcEditor ArcToolbox If you want to learn more about the other components, you need to take additional classes 3

4 ArcCatalog ArcCatalog is the application that you will use to: Create geodatabases and their various components Establish coordinate systems and spatial extents for your GDB Manage date in a variety of formats ArcMap You will use ArcMap to: View your spatial and tabular data To create map layouts for printing To query, subset, and aggregate your data Do some spatial analysis 4

5 ArcEditor ArcEditor is an application that works inside of ArcMap You will use ArcEditor to: To create new features in a feature class To modify existing features To update records in tables ArcToolbox You will use ArcToolbox for: Data processing Data conversion Data management The Toolbox can be accessed from inside ArcCatalog or ArcMap 5

6 The ArcGIS Workspace The ArcGIS workspace may contain a variety of files and file types Geodatabases Coverages Shapefiles GRIDs Relations Non-ArcGIS directories and files Most of these are managed within ArcCatalog Non-ArcGIS directories and files are not visible in ArcCatalog Components of a Geodatabase Relationship Class Feature Classes Feature Topology Datasets Class Geodatabases may contain all of the following Feature datasets Feature classes Tables Topology Classes Relationship Classes Table 6

7 Geodatabase Hierarchy? In ArcCatalog, the structure of the geodatabase appears hierarchichal Nested elements Some elements require parent elements to operate correctly In truth, this hierarchy is more apparent than real It is about relationships between tables Hierarchy? Geodatabase Nested Feature Data Sets Nested Feature Classes 7

8 Hiearchy? Feature Datasets In geodatabases, a feature data set is a collection of feature classes that share the same spatial reference. Because the feature classes share the same spatial reference, they can participate in topological relationships with each other such as in a geometric network, linear network, or topology. Several feature classes with the same geometry may be stored in the same feature dataset. Object classes and relationship classes can also be stored in a feature dataset. 8

9 Feature Data Set and Spatial Properties The following must match between feature class and feature dataset Coordinate System X, Y Domain Z Domain M Domain If they don t match Feature class won t import Feature class won t appear Creating a Feature Data Set 9

10 Feature Classes The conceptual representation of a category of geographic features. When referring to geographic features, feature classes include point, line, area, and annotation. In a geodatabase, an object class that stores features and has a geometry field type. Feature Class Nested Feature Classes Stand-Alone Feature Classes 10

11 Feature Class Creating a New Feature Class 11

12 Integrated Feature Dataset vs. Feature Class You must use integrated feature datasets if you want your feature classes to participate in topological relationships You may want to use integrated feature datasets to help normalize spatial extents for a variety of feature classes to help organize your data into logical groups You may want to use stand-alone feature classes when topological relationships are not an issue when the feature has a unique spatial extent Instructor Demonstrations Using the SVRD dataset, the instructor will now demonstrate: ArcCatalog ArcMap ArcEditor 12