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Why the U.S. National Grid?�(Part 2 - Alternatives?)

10

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Sherburne County Govt Center�13880 Highway 10�13880 Business Center Drive�Elk River, MN 55330-4601

or

S13-R20E-T1S MDM refers to: Township 1 South, Range 20 East, Section 13, Mount Diablo Meridian, or the 13th section in the first township south of the baseline and 20th township east of the principal meridian (Example)

or

15 489960.0 4959860.0 UTM

or

N444731.4 W0930736.9

or

15T VL 5139 1688 �

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GPS and Lat/Long to the Rescue – Not So Fast

N45.021855 W93.167324 (degrees, decimal degrees)
N45^o01’15” W93^o10’34” (degrees, minutes, seconds)
N45-1.254 W93-10.556 (degrees, minutes, decimal minutes)

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Converging Lines of Longitude = Bad Math

“60” based math to boot!

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Proprietary Grids are Useless!

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Rural Grids

Two different markings… Same location…. Road versus house

Colliding rural fire grids – one side of the street versus the other!

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Now Toss In a Disaster - Address Grid Gone?

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No, I Mean Really Gone

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USNG (MGRS): 54S VH 97719 32022

What’s the Address of This House in Sendai, Japan?

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And If You Have a Disaster – You’ll Need a Grid

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Original Recovery Grid

The following week, the Safety folks came to GIS for help. They needed a way to reference the recovery effort. When people needed to meet or reference an area to search, they needed a common reference grid. We were able to take the August 3 flight and stretch it to a rough facsimile of reality, and generate a 50’ x 100’ reference grid. Each box is uniquely numbered, and each has a qualifier as to whether is has river in that box, or is north or south of the river. We produced close to a dozen large wall size maps, and over 75 smaller maps for people on-site. This has been an invaluable tool for this effort.

Later we added the fences, gates, and trailers from the maintenance folks. We labeled the roads and the important buildings. All of this is available in PDF format from the GIS Support web site, and now on the COP site as well. Again, it’s not about the map, but the information behind the map, and using the mapped data as a tool to organize our efforts.

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USNG Recovery Grid