An Alternative to Latitude / Longitude Latitude / Longitude – The U.S.

An Alternative to
Latitude / Longitude –
The U.S. National Grid
Randy Knippel
Dakota County
MnGEO Emergency Preparedness
Committee
Maps!
Map
Books
Map
Series
1
U. S. National Grid
• National standard since 2001
• Adopted by federal agencies
National Search
And Rescue
Committee
Federal-level committee
formed to coordinate civil
search and rescue (SAR)
– FEMA, DHS, NGA, USGS
• Adopted by several states
– Florida, Missouri, North Carolina, others
– Minnesota (March 25, 2009)
• Military Grid Referencing System (MGRS)
– National Guard
– All NATO forces
Why?
• Multiple grids
– Global, State, County, Assumed
– Needed one for everyone
• Need efficient location referencing
• Need interoperability
– Across jurisdictions
– Local, state, federal, military
What about Lat / Long?
• Not intuitive
– Degrees, minutes, seconds
• Several formats
– DMS, DMS.sss, DM.mmm, D.ddd
– Longitude
• +/• West / east
• Increases right to left
2
What about Lat / Long?
• How big is a degree?
Map
VK75
(15T VK 7 5)
– It varies
• 69 miles at the equator
q
• Longitude gets smaller toward poles
• 50 miles in Dakota County
7456
(15T VK 74 56)
• Distance calculations are difficult
Map
7456
(15T VK 74 56)
741565
(15T VK 741 565)
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