Adjusting MGRS to Map Scale

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04-04-2023 05:44 AM
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awalker2055
Emerging Contributor

I'm trying to make a simply layout with an MGRS overlay with a map scale of 1:25,000. This is to be printed on a 8.5 x 11 sheet of paper (the map frame itself is 8 x 10.5). I want to be able to use the MGRS overlay to plot points using a protractor once I print it off. When I tested this to see if it works, the MGRS grid is larger than the appropriate scale on the protractor I intend on using for mapping, despite the scale of the map and frame being 1:25,000. Am I misunderstanding how MGRS works or does some adjustment have to be made in ArcGIS pro for this to work?

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VaibhavS
Regular Contributor

There are two MGRS grid style items included in the ArcGIS Pro systems styles, one designed with 1,000 meter gridline intervals and one designed with 10,000 meter gridline intervals for smaller scale maps. I believe we would have to select the correct style. 

Please check if it helps: 

MGRS Grids: https://pro.arcgis.com/en/pro-app/latest/help/layouts/mgrs-grids.htm

Calculating MGRS values for features: https://desktop.arcgis.com/en/arcmap/latest/extensions/defense-mapping/calculating-mgrs-values-for-f...

 

 

 

 

VaibhavS
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KanaiGooding
New Contributor

I can confirm this is a HUGE problem.  MGRS lines in ArcGIS seem to be spaced approximately 1100m apart.  The scale bar seems to work correctly. I have done this with known distances on maps, and MGRS grids seem to be wrong in the ArcGIS software.  

I've made recommendations to the boss to cancel subscriptions to the software until this is resolved.  As my shop cannot use ARCGIS for mapping purposes due to this error.  Unless there is a fix or we are doing something wrong, ESRI is failing to provide the basic needs to it's mil customers.  

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LanceShannon
New Contributor

I am APMS for an Army ROTC and was trying to create a map for training/Landnav and ran into the same issue. After going through all my settings, I found I had a unit / coordinate system mismatch between my MGRS grid and basemap. My Grid in "Layout" was correct. I had to change the base map Coordinate System settings in "Contents" to be compatible with WGS84 UTM, 14N. (Originally had them on WGS84 Web Mercator [auxiliary sphere] and did not know it.) This corrected all the scaling and alignment issues. Double checked against a map from an army post in our area and alignment was correct and worked precisely with the standard protractor once printed. [Used ArcPro 3.3.0]

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