topic Re: Reconciling projections in a project migrated from ArcMap to ArcGIS in ArcGIS Pro Questions

Reconciling projections in a project migrated from ArcMap to ArcGIS

CharlesEiseman — Thu, 12 Dec 2024 19:08:11 GMT

Hello all,

I'm just starting to use ArcGIS Pro and have imported an existing MXD file to continue the work I had been doing in ArcMap until I was forced to change platforms. I am trying to add points to an existing shapefile, and each point I draw appears about 4 feet to the south of where I'm trying to draw it. I assume this is a problem with the shapefiles and map not all having the same projection or datum, but I can't figure out how to fix this, and I want to make sure I don't mess up any of the existing data. All of the shapefiles were working fine together in ArcMap. Can someone please explain what I should do?

Thanks,

Charley

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

DavidPike — Thu, 12 Dec 2024 19:22:59 GMT

You probably have a specific transformation set in ArcMap that you need to specify in ArcGIS Pro

https://support.esri.com/en-us/knowledge-base/apply-a-geographic-datum-transformation-in-arcmap-14624-000002828

https://pro.arcgis.com/en/pro-app/3.3/help/mapping/properties/specify-a-transformation.htm

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

CharlesEiseman — Thu, 12 Dec 2024 19:54:47 GMT

Thanks. I had not set any kind of transformation; I'm just blundering along with the bare minimum knowledge I need to make simple maps. But I learned that my project is in GCS_WGS_1984, and when I right-click in the Contents in ArcGIS Pro, it's telling me to choose transformations from four different datums. So ArcMap magically did all of this automatically, and ArcGIS Pro has been designed so that I have to do all it manually? Why would that be--how is it an improvement?

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

CharlesEiseman — Thu, 12 Dec 2024 19:58:30 GMT

And also, how do I know which WGS_1984 to transform to? The options include WGS_1984 1, WGS_1984 2, etc., but I don't see just plain WGS_1984.

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

DavidPike — Thu, 12 Dec 2024 20:33:51 GMT

What's the coordinate system of your shapefile? Could also just be something messed up with the import of the old MXD.

What's your basemapping in? If it's web mercator it may be doing something odd in having to reproject the mapping, and then have another coordinate system to transform from your shapefile.

Would try a new project and just bring the shapefile into it, and/or export the shapefile in Pro again. Also ArcGIS Pro should select the 'best' transformation usually so I'm thinking something is off with the shapefile or it has some custom settings.

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

Robert_LeClair — Thu, 12 Dec 2024 21:09:53 GMT

So ArcMap was more manual in nature when it came to geographic transformations. When I taught the old ArcMap classes, I would ask the question - "How many people ever saw a Geographic Transformation window appear when they added data to a data frame? How many people clicked close because they didn't know what it meant? " (most by the way) So likely someone either did or did not set a GT in ArcMap for the saved *.mxd. If it was not set, then error is being introduced into your data.

ArcGIS Pro, on the otherhand, is automatically setting the correct geographic transformation for you. Typically the first one populated in the list is generally correct. But if you know GTs and coordinate systems like crazy good, then you can choose the other methods. So opposite of what you wrote really. ArcMap is way more manual and ArcGIS Pro is way more automatic - so yes, an improvement.

My guess is you've got a workflow issue somewhere. Either in ArcMap where a GT was never set or if it was set, maybe was incorrect?

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

CharlesEiseman — Thu, 19 Dec 2024 15:09:34 GMT

Thanks - I Just accepted the first transformation in the list (even though it seemed to be going in the wrong direction) and that seems to have worked.

Re: Reconciling projections in a project migrated from ArcMap to ArcGIS

DavidPike — Fri, 20 Dec 2024 17:39:56 GMT

Just to add that the transformation is bidirectional