Warnell GIS and Spatial Analysis

This is a short refresher document about digitizing in ArcGIS 9x. The steps summarized are as follows:

You can use the Watershed Delineation Tools (arcscripts.esri.com) to quickly delineate watersheds in ArcGIS. 

There are many ways to get your GIS data into Google Earth.  If you have ArcGIS 9.x installed, you can find the tools to export your data as a kml or kmz in ArcToolbox.  For those who don't, here is one way you can get your shapefiles in Google Earth.

I don't think I can do any better than what these guys have already done.  Here are links to 3 searchable GIS dictionaries.

ESRI

Association for Geographic Information (AGI)

GIS Lounge

OK.  You say you have some GIS data you would like to view, but are not sure how to do it.  Well, you are in luck.  There are quite a few free GIS data viewers available which make this task easy and inexpensive.  I have listed a few of my favorites (over here).

• The Extract by Export command allows us to save a portion of a raster.  Do not use this method if you need to clip a raster that has more than 3 lay

1. Load the image you want to clip
2. Zoom into the region you are interested in
3. Open the theme properties (right-click on layer name > properties)
4. Under the Display tab, display the bands you want to include and Hit OK
5. Open the Export dialog (right-click on the layer name > Data > Export Data )

• Change

• Use the CLIP command to subset a raster by entering the max/min X & Y coordinages of the area you are interested in.  This results in a new rectangular image.

• The Extract by Mask command allows us to subset a raster using a shapefile (or another binary raster image: 1=keep, 0=remove).

1. ArcToolbox > Spatial Analyst Tools > Extraction > Extract by Mask
2. Input Raster: load the image you would like to clip
3. Input Raster or Feature Mask:  Point to an existing raster or vector dataset that represents the area to which you want to clip the image
   • this can be a vector polygon or a raster image whose pixels are either 0 (do not include the pixel

Subsetting Rasters

• Extract by Mask
• Clip
• Export