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I’m helping my organization convert from ArcGIS Desktop 10.8 to ArcGIS Pro 3.2. We have a local site-specific X, Y, Z coordinate system, in engineers feet (feet in tenths), based on a main datum (N1000, E1000, Z100). For ArcMap 9.3 and now ArcMap 10.8.2, we’ve maintained an undefined coordinate system in the Data Frame Properties, with feet as the map and display units, and our shapefiles have undefined coordinate systems too.

As I’m learning how to convert from ArcMap to ArcGIS Pro, I’ve found that ArcGIS Pro requires a coordinate system to be defined, to continue using GIS in the manner that we have. The main problem I can see now is that there are “no editable layers” since the “layer cannot be edited with an unknown coordinate system.”

It looks like a Local projection is the answer, I guess that I could define a Local coordinate system in ArcMap 10.8, and then import to ArcGIS Pro. Or I could do define the Local coordinate in ArcGIS Pro.

I made an attempt in ArcGIS Pro -- in Layers/Properties/Coordinate Systems, I set up a new “Local” coordinate system, with False Easting=0, False Northing=0, Longitude of Center=1000, Latitude of Center=1000. As far as I can tell, the coordinates show up correctly on the map, but then I will need to define the coordinate systems for each of the shapefiles.

Is it better to define the Local projection in ArcMap, or in ArcGIS Pro?

PolyGeo
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ArchaeoGIS7
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1 Answers1

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I continued working on defining local site-specific coordinate systems for ArcGIS Desktop 10.8 to ArcGIS Pro 3.2, here is a solution I found:

1.) Define a Local Coordinate system in ArcGIS Desktop 10.8: Right click on “Layers” in the Contents; select “Coordinate System” tab. In the dropdown menu for “Add Coordinate System”, Choose “”New > New Projected Coordinate System.” When the “New Projected Coordinate System” box opens, name the file; in the “Name:” dropdown menu choose “Local”. Then fill out the parameters (this is what I did for my site’s coordinate system: False Easting=0; False Northing=0; Scale Factor=1; Azimuth=0; Longitude of Center=1000; Latitude of Center=1000. Change Linear units to feet to match my grid). This used WGS_1984 as the Geographic Coordinate System (this was the default option, I’m not sure if that matters for this). Choose OK. The new Local projection appears under the Custom list; right click the file, and Save As. I put the named .prj file in the ArcGIS Pro folder that I’m using, so it’s easy to find.

2. Define Coordinate system for shapefiles in ArcGIS Desktop 10.8: Open ArcCatalog. Go to the folder with shapefiles to be imported into ArcGIS Pro 3.2. For each shapefile, right click “Properties”; on the “XY Coordinate System tab, select the Local projected coordinate system that I made. Add it to the Favorites so it’s easier to find. Click Apply, then OK. Do this for each shapefile to be imported to ArcGIS Pro 3.2.

3. Open ArcGIS Pro 3.2: Choose “Start Without a Template”; select “Import Map” on the ribbon; open the ArcGIS Desktop 10.8 project with the Local coordinate system. In the Contents frame, right click on "Layers", choose "Properties/Coordinate Systems", and the Local projection should be there. For the shapefiles with the Local coordinate systems defined in ArcMap 10.8, in the Catalog Frame, right click, "Properties"/"Spatial Reference" and the coordinate system will be there.

PolyGeo
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ArchaeoGIS7
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  • "Longitude of Center=1000; Latitude of Center=1000"? Longitudes can only be in a range of -180 to 180, and Latitudes in a range of -90 to 90. – Pointdump Feb 01 '24 at 14:36
  • That's a good point. I'm not sure how to answer that. N1000/E1000 is the center of the arbitrary grid that I'm working with. Maybe it should be False Easting=1000 and False Northing=1000? That is what this answer link seems to say – ArchaeoGIS7 Feb 01 '24 at 20:10
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    If you're going to just be overlaying data layers that represent the same place on the ground using that 1k,1k as the center coordinate pair, then you're doing okay. If you want to georeference a layer so that it overlays with 'real world' data using a known coordinate system, there's more to do. Try looking at the doc for spatial adjustment or maybe georeferencing. – mkennedy Feb 07 '24 at 02:19
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    Using 1k,1k for the false easting/northing is the right way to go, but you would need to identify the correct latitude,longitude values for the center of your unknown/local coordsys. – mkennedy Feb 07 '24 at 02:20