USING UTM MGRS USNG Monica Spicker Some slides

USING UTM, MGRS & USNG Monica Spicker Some slides adapted from Harry Frank 2008 BMOC

Objectives Understanding UTM system Finding coordinates of a point Plotting a point BMOC

Universal Transverse Mercator (UTM) þ þ þ þ NATO system Metric units (meters) World is split into 60, 6º degree zones Spokane area is Zone 11 N Distorted above North 84º, and South 80º, not applied above these latitudes. Smallest grid unit on USGS 1: 24000 maps is 1 km. May be different on different scale maps! Coordinates get larger going east (easting) from the zone meridian and larger going north (northing) from the equator. BMOC

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Identifying the grid 466 467 5157 (Easting) 5157 Map 5156 (Northing) 466 467 BMOC

Determining Coordinates: Easting the easting first: to the Find the. Determine nearest smaller coordinate From. LEFT the object map ( ) go (W) ofon your point to the bottom (or top) edge of the map 5157 5156 465 466 BMOC

Determining Coordinates: Easting 4 6 5 0 0 0 BMOC

Determining Coordinates: Easting Divide the distance between the coordinate to the left of your point and the coordinate to the right of your point into tenths 3 tenths 465 This is hundreds of meters 466 BMOC

Determining Coordinates: Easting 4 6 5 3 0 0 BMOC

Determining Coordinates: Northing Find From the nearest pointcoordinate on map ( below ) look(S) to the of your left point (or right) edge of the map 5157 5156 465 466 BMOC

Determining Coordinates: Northing 5 1 5 6 0 0 0 BMOC

Determining Coordinates: Northing Count or estimate the number of tenths from the coordinate BELOW your point TO the corner. 5157 8 Tenths This is hundreds of meters 5156 BMOC

Determining Coordinates: Northing 5 1 5 6 8 0 0 BMOC

Final Coordinates of 465300 E 5165800 N But we can go finer, if we use a template BMOC

Using a Template Must match map scale! Can estimate how far into box on a scale of 1 to 10 to find nearest ten meters. 5165820 N Starting corner: 465000 E 5165000 N Template placed on map at kilometer grid corner 465360 E BMOC

Another Way to Use the Template Put the 0 corner of the template on the point. Read where the block margin hits the template scales. 465360 E Starting corner: 465000 E 5165000 N 5165820 N BMOC

Determining Coordinates 489520 E 5315440 N Start here. 489000 E, 5315000 N BMOC

Practice Exercises BMOC

Plotting Points Underline the last 3 digits of each coordinate. What’s not underlined are the margin coordinates. Example: 490150 E 5315325 N Use template to determine position within the kilometer box. BMOC

490120 E 5315340 N Start here. 490, 5315 Plotting 490120 E 5315340 N BMOC

Practice Exercises BMOC

MGRS and USNG Military Grid Reference System US National Grid System USNG and MGRS are identical Based on UTM Default datum is NAD 83 Includes Ø UTM zone (number and letter) Ø A two letter grid designator that replaces the smaller written UTM number in the margin Ø only the ending 5 numbers. More can be truncated, if you are not going down to single meters. Most GPS support MGRS. Most commercial maps do NOT. BMOC

Example in UTM: 11 T 490150 E 5315325 N in MGRS: 11 T MP 90150 E 15325 N NAD 83 : 1 meter 11 T MP 9015 E 1532 N NAD 83 : nearest 10 meters 11 T MP 901 E : nearest 100 meters 153 N NAD 83 BMOC