1 / 30

Introduction to the Geodatabase

Introduction to the Geodatabase. What is a Geodatabase? What are feature classes and feature datasets? What are domains Design a personal Geodatabase Import data to a Geodatabase. What is a Geodatabase?. A relational database that contain geographic information.

helene
Télécharger la présentation

Introduction to the Geodatabase

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to the Geodatabase

  2. What is a Geodatabase? • What are feature classes and feature datasets? • What are domains • Design a personal Geodatabase • Import data to a Geodatabase

  3. What is a Geodatabase? A relational database that contain geographic information • A container for tables, feature classes, feature datasets…. • Tables – attributes of rows and columns • Standalone feature classes (conceptually like shape files) • Feature datasets (a collection of feature classes) • Rules and relationships

  4. Feature classes….. • Store geographic features represented as points, lines, or polygons, and their attributes; • Can also store annotation and dimensions. • Tables may contain additional attributes for a feature class

  5. Feature datasets….. • Feature classes can be organized in Feature datasets. • All feature classes in a feature dataset share the same coordinate system. • Feature classes in a feature dataset can be organized into a geometric network. The network maintains topological relationships between its feature classes.

  6. Personal vs. Multiuser Geodatabase Personal geodatabase - stores data in a Microsoft Access database - size limit 2 GB - directly read through ArcCatalog - does not support raster data Multiuser geodatabases - data stored in IBM DB2, Informix, Oracle, or Microsoft SQL Server - connected through ArcSDE or direct - ArcSDE license necessary for editing - supports raster data

  7. Why Geodatabase? • All data (vector, raster, address, measures, CAD, etc.) is stored together in a commercial off-the-shelf DBMS • Simplify support and maintenance, and reduce costs • Allows multi-user access (with ArcSDE license) • Support for intelligent features, rules, and relationships between feature classes

  8. More advantages….. • Dynamic Geocoding • Annotation subclasses • Subtypes within Feature classes • Coded attribute and range domains • Improved topology and editing

  9. Confused? • The geodatabase may seem complicated….. …however they are simply modern equivalents of shapefiles and coverages stored in a commercial database.

  10. Geodatabases in ArcGIS • - Geodatabases can be created and managed easily using the standard tools in ArcCatalog • ArcMap and ArcToolbox provides tools to work with geodatabases

  11. Creating a Geodatabase Think before you create • Design process • Create an empty Geodatabase in ArcCatalog • Define the database structure • Set spatial reference and coordinate domains • Load data • Define topology rules and relationships

  12. Design process • What data layers to include in the geodatabase • Shape files – Coverages • Look-up tables • How to organize the feature classes into logical feature datasets • Think about what topolygy rules you may want to apply – how are the feature classes related to each other spatially?

  13. Create a new Geodatabase in ArcCatalog

  14. Migrating existing data into the Geodatabase • Shape files and coverages are converted to feature classes • Attributes can be left out or renamed • CAD data, dBase files, annotation etc. can be imported • Data of the same spatial extent can be imported to the same feature dataset

  15. Importing existing data • In ArcCatalog or ArcToolbox • Tools and wizards are available • Works with coverages, shapefiles, tables, CAD etc.

  16. Creating Feature Datasets • Right-click on the geodatabase – New – Feature Dataset • Name the Feature Dataset and define the coordinate system • Set X/Y domain • Set Z domain and M domain • Set manually or import from existing data sets

  17. Coordinate Domains Lost data Max X and Y is 2.14 billion Y Large area Smaller precision (1,000) Small area larger precision (100,000) X (0,0)

  18. Coordinate Domains • The coordinate domain defines the area you can make edits in • X and Y max is 2.14 billion for the database • Default domain is 21000, 21000 • Define your coordinate domains correctly the first time – they cannot be changed • You can have a different coordinate domain for each feature class

  19. What is max/min X and Y on the map? Max X and Y Min X and Y

  20. Setting X/Y Domain Precision 1000 Min X ~ 2,145,320 Max X ~ 2,657,580 Min Y ~ 1,632,610 Max Y ~ 1,967,940 1 ft units, 1/1000 ft accuracy Precision = 1000/1 = 1000 (good enough)

  21. Coordinate Domains Max X and Y is 2.14 billion Y Most of the data is here in the database Large expansion options to the north and east X (0,0)

  22. Coordinate Domains Calculations Min X ~ 2,145,320 Max X ~ 2,657,580 Min Y ~ 1,632,610 Max Y ~ 1,967,940 Precision 1000 These coordinates would put the data in the lower left corner – however we want to shift this to be able to expand in all directions (MinX + MaxX)/2 – (2.14 x 109) / (1000 x 2) = X min 2,401,450 – 1,070,000 = 1,331,450 (MinY + MaxY)/2 – (2.14 x 109) / (1000 x 2) = Y min 1,800,275 – 1,070,000 = 730,275

  23. Coordinate Domains Calculations (MinX + MaxX)/2 + (2.14 x 109) / (1000 x 2) = X max 2,401,450 + 1,070,000 = 3,471,450 (MinY + MaxY)/2 + (2.14 x 109) / (1000 x 2) = Y max 1,800,275 + 1,070,000 = 2,870,275 Shifted x/y domain Default x/y domain Min X = 1,331,450 Max X = 3,471,450 Min Y = 730,275 Max Y = 2,870,275 Precision 1000 Min X ~ 2,145,320 Max X ~ 2,657,580 Min Y ~ 1,632,610 Max Y ~ 1,967,940 Precision 1000

  24. Coordinate Domains Max X and Y is 2.14 billion Y Most of the data is here in the database Large expansion options in all directions X (0,0)

  25. The shifted x/y domain allows for editing within this window Max X, Max Y Min X, Min Y

  26. Why create Feature Datsets? • Data organization • Topology rules • Shared boundaries • Geometric networks

  27. Subtypes in feature classes Subtypes can only be created in ArcEditor and ArcInfo - A subtype is a group of objects that have similar properties within the Geodatabase For example the attribute ‘ZoneCode’ may have subtypes: - Commercial, Residential, Industrial Landcover vegetation types may have subtypes: - Forest, Agriculture, Rangeland, Urban

  28. Attribute Domains • Attribute domains are properties of the Geodatabase • - Multiple objects may use the same domain • - Can be created using the Domains properties dialog box • Defines legal values for field attributes • - Range domains (allowable numeric value range) • - Coded value domain (in dropdown menus)

  29. Questions?

More Related