1 / 28

GUS: 0265 Fundamentals of GIS

Learn about the raster data model and its operations in GIS. Understand concepts such as raster resolution, data compression, map algebra, and cartographic modeling. Explore various functions and program controls to manipulate raster data efficiently.

wgraybeal
Download Presentation

GUS: 0265 Fundamentals of GIS

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. GUS: 0265Fundamentals of GIS Lecture Presentation 4: Raster Data Model and Operations Jeremy Mennis Department of Geography and Urban Studies Temple University

  2. Raster Data Model • A raster representation is composed a series of layers, each with a theme • Typically used to represent ‘field-like’ geographic phenomena

  3. 1 1 1 2 3 1 1 1 2 3 2 2 2 2 2 4 4 4 2 3 4 4 4 2 3 Raster Resolution The distance that one side of a grid cell represents on the ground = grid cell resolution The higher the resolution (smaller the grid cell), the higher the precision, but the greater the cost in data storage

  4. Raster Data: ArcGIS

  5. Data Compression Common Methods: • run length encoding • value point encoding • chain codes • block codes • quadtrees

  6. Run Length Encodingand Value Point Encoding

  7. Map Algebra and Cartographic Modeling A raster modeling language, and an approach to GIS analysis design, developed by J.K. Berry and C. Dana Tomlin in the late 1970s - early 1980s. It now forms the basis for grid-based analysis in ArcInfo (GRID and Spatial Analyst) and other GIS packages.

  8. Map Algebra A set of formally defined manipulations on raster data. Operators: Fundamental mathematical and logical operations on raster data Functions: Complex combinations of operations

  9. Functions: Types Higher order data manipulations on raster grids built from the more basic operators. Local: compute on single-cell basis Focal: compute on a neighborhood Zonal: use zones derived from a separate grid for evaluation Block: like zonal, but the result is assigned to an entire ‘block’ of cells Global: compute on the entire grid

  10. Functions: Local – Single Values

  11. Functions: Local - Mean

  12. Functions: Focal – Immediate Neighborhood

  13. Functions: Focal – MajorityMinMean

  14. Functions: Zonal – Entire Zones

  15. Functions: Zonal - Max

  16. Functions: Global - Distance

  17. Program Control: Statements and Programs Statement: notation to represent operations and functions e.g. NEWLAYER = LocalFUNCTION of FIRSTLAYER and SECONDLAYER Program: notation to represent a procedure; i.e. a sequence of statements in which each statement operates on the result of a previous statement

  18. Program Control: Programs

  19. Program Control: Programs

  20. Program Control: Programs

  21. Program Control: Programs

  22. Program Control: Programs

  23. Cartographic Modeling in ArcInfo: ModelBuilder Locating Suitable Sites for a Waste Dump

  24. Cartographic Modeling in ArcInfo: ModelBuilder

  25. Cartographic Modeling in ArcInfo: ModelBuilder

  26. Cartographic Modeling in ArcInfo: ModelBuilder

  27. Cartographic Modeling in ArcInfo: ModelBuilder

  28. Cartographic Modeling in ArcInfo: ModelBuilder

More Related