1. NR 322: Raster Data Jim Graham Fall 2008 Chapter 7

2. Vector File Formats E00: Coverage exchange format –Decompress to get a coverage file KML: Keyhole Markup Language –Not georeferenced –Maybe with a prj file? STDS: US Government’s new vector format

3. Geo-Referenced Raster Known Projection and Datum (X1,Y1) (X2,Y2) (X4,Y4) (X3,Y3)

4. Geo-Referenced Raster Known Projection and Datum Width and height of a pixel in map units (X1,Y1) Width in Pixels Height in pixels

5. Geo-Referenced Raster Known Projection and Datum (X1,Y1) (X3,Y3)

6. Continuous vs. Categorized Continuous: –Like photographs –Satellite and aerial photos –Best for analysis Categorized or discrete –Land Cover –Eco-regions –Limited analysis –Careful on precision and accuracy

7. Categorical vs. Continuous

8. “No-Data” or NULL Values Rasters are always rectangular No-Data values are “transparent” and are not used for calcualations

9. GeoReferenced File Formats GRID: ESRI’s format GeoTIFF: Excellent support MrSID: LizardTech IMG: ERDAS ECW: ERMapper BIL, BIP, BSQ: See header “ASCII” or “GRID ASCII”

10. World Files Contains: –X-dimention Pixel size in map units –Y-axis rotation –X-axis rotation –Y- dimension Pixel size in map units (negative) –X-coordinate of upper-left pixel –Y-coordinate of upper-left pixel Image file contains width and height

11. Not Geo-Referenced BMP PNG GIF Maybe with a world file and prj?

12. Tagged Image File Format TIFF Can be georeferenced (GeoTIFF) –Can tell in ArcCatalog or ArcMap TIFF w/world file –Also need Projection and Datum (prj?) Can be compressed –Run-length – Categorical data –LZW – Categorical data –Huffman encoding – Categorical data –JPEG- Continuous data (don’t used on Categorical data!)

13. JPEG Joint Photographic Experts Group Widest used photo format JPEG2000 –Completely new format! –Can be georeferenced

14. GRIDS ESRI’s native raster format Pyramids Not an exchange format!

15. ASCII format NCOLS 10 NROWS 9 XLLCORNER 1000 YLLCORNER 1000 CELLSIZE 1 NODATA_VALUE -9 -9 -9 1 1 0 1 0 1 -9 -9 -9 -9 1 1 2 2 2 1 1 -9 -9 1 1 1 2 2 2 2 3 3 Etc. See example

16. Types of Rasters Digital Elevation Model (DEM) Digital Raster Graphic (Topos) Satellite and Aerial Photos Land Cover & other natural characteristics Cost Distance & other economic Population, taxes, etc. Your own!

17. Digital Raster Graphic

18. Digital Elevation Model (DEM)

19. Hill-shade

20. Contours

21. DEM Cross Section 2000m 1900m 2100m 2200m

22. Slope

23. Calculating Slope DEM Cross Section

24. Aspect – Direction of the slope Slope Aspect (Direction) Angle Rise Run Slope = (Rise/Run) * 100%

25. Aspect

26. Hill-shade

27. This weeks lab Download DEM Create slope, aspect, hill-shade maps Make a map showing all 4 types How many scale bars do you need? How many legends to you need?