U.S. Department of the Interior U.S. Geological Survey Building Base Maps

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-2 Managing large image collections Large images can easily exceed the 2-GB limit on file size ESRI offers two major ways to manage spatially tiled images –Image Catalogs –ArcSDE Rasters (has 5 ways to handle, but beyond scope of this class)

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-3 Raster (a.k.a Image) Catalogs Group of raster files covering a similar theme and sharing coordinate system Often same format and symbology Examples: –Map series (DRGs) –Orthophotos (DOQs)

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-4 Raster Catalogs Display multiple rasters without having to merge them into larger rasters Supported very well in ArcView 3 Supported in ArcPlot, but can’t do a transparent NODATA Also supported in ArcMap, but you need a script to do transparent NODATA

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-5 Raster Catalogs Format: any table with columns: IMAGE, XMIN, YMIN, XMAX, YMAX IMAGE is a pathname to the raster Symbology from first raster in catalog ArcObjects Online sample code exists to help in symbolizing catalogs

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-6 Working with Image Catalogs Prerequisites: –Images in supported formats –Georeferenced, spatial reference specified in ArcCatalog –All images must use the same colormap –If overlapping, need a special value for overlaps or NODATA areas

Image Catalog Procedures: DRG Example Get DRGs. Best source: NRCS state offices on CD Decide on projection, datum Clip_project_DRG.aml –Project if necessary –Trim collars Assign spatial reference: BatchRasterSpatialRef.bas Use a system variable for base of paths in image catalog for portablility

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-8 Create Image Catalogs Arc CREATECATALOG command Arc ADDIMAGE command Drgcatalog.aml does both, adds all images in a folder to the catalog Folder2ImageCatalog.bas works in ArcCatalog, can do.SID files Other AMLs: –copyimagecat.aml (copies images) –trimimagecat.aml (deletes images from disk)

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-9 Raster Catalog Pitfalls Make sure all files and folders are NOT read-only Do NOT load into ArcMap until you are sure all paths are correct and all images have spatial references If you load it with a bad spatial reference you will never be able to load it correctly

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-10 Changing Symbology for an Raster Catalog No Symbology tab There’s no way to store a transparent color in a TIFF colormap Must use a script to get a ‘renderer’ from one image, apply it to all ChangeCatalogSymbology.bas

StreamStats Data Prep Workshop Oct 21-22, 2003Page 6-11 Other base maps NLCD Shaded relief at both 90- and 30- meter resolutions Precip, other layers used Make these TIFFs, they work better in ArcIMS