By Will Walsh on 2/21/2009 6:47 PM
With Wildland Fire season coming upon us it is a good opportunity to review our mapping standards. For our purposes most of us do not need detailed geospatial training but we can benefit from an understanding of two topics: Grid Systems and Reference Datum. I know this is starting to sound like your 7th grade math class, so bear with me.
A Grid System allows the location of a point on a map to be described in a way that is meaningful and universally understood. The common Grid Systems used in the United States are:
Geographic - uses degrees of latitude and longitude.
Public Land Survey - used in Colonial America for surveying. You might know it as Township/Range.
UTM - Preserves shape, and allows for precise measurements in meters.
State Plane - Developed for local surveying, with minimal distortion.
For our purposes we use a Grid System to tell someone where we want them to land to pick up a patient or drop a load of water or retardant. When communicating location... Read More »