Thursday, December 6, 2012

"Clip Before You Go"

Today I spoke with Brian Quinn, a GIS Analyst for the County of Marin, California. We were discussing how he can support Marin County SAR as they begin implementing MapSAR and building out Minimum Essential Datasets. On the one hand most vector data can be collected ahead of time and stored as geodatabase and/or layer packages. But sometimes you need to quickly grab new data on the fly. Together, we thought of a really quick way the Marin SAR Team could use Free and Public ArcGIS image services to clip raster data (basemaps, elevation models, imagery) before leaving the office.

Here is what we tested in ArcGIS Desktop.


  • Next Zoom into an Area of Interest and open the Image Analysis Window


  • Then use the Clip and Export buttons to grab the data you need


  • Finally, use your Using GIS for WiSAR textbook to figure out the best practice for adding this to your Minimum Essential Dataset (MED) within the MapSAR folder structure


These clipped rasters will now be available when you disconnect and can be added to your MapSAR document and printed on your maps. There will be size limitations but for most incident specific extents this should work. In the long term, you will need a more holistic approach to Data Management. See the Using GIS for WiSAR textbook.

For more information, see the Help on the Image Analysis Window. For another example of imagery deployed via free web services see the California Department of Fish and Game Map Services website.

This is just one of many ways you can collaborate with your local GIS Specialist. Most GIS Specialist are pretty friendly and eager to help because they likely found their profession in GIS by looking for meaningful work and making a difference. If you do SAR work, you likely have something in common. So - give them a call, buy them a beer, invite them to a SAR meeting, and send them to our SARGIS Discussion Group!

1 comment:

  1. This works reasonably well. But for NAIP imagery (for instance) the file size limit can be a problem (about 1GB??) Also, I get significant lightening of the image -- almost washing out for granite and other light features. Haven't figured out what settings I need to use, but they must exist... .