Why do results for Grid Index Features tool in ArcMap and ArcGIS Pro differ?

Question

I'm trying to create grids for an area using the Grid Index Features tool in ArcGIS Pro. The grids should be a specific width and height and cover the given area. I've created a shapefile for the area which is used for the "Input Features" selection. I uncheck "Generate Polygon Grid that intersects input features layer or datasets" because I want the grid index to expand beyond the area polygon. ArcGIS Pro then auto populates the "Polygon Grid Origin Coordinate" and "Number of Rows" and "Number of Columns." HOWEVER, ArcGIS Pro and ArcMap auto-populate with differing information. (See attached screenshots.) ArcGIS Pro creates thousands of grids vs the correct number in ArcMap.

Note: The projection is the same for both ArcGIS Pro and ArcMap maps. I've also tried setting the projection in the Environments Tab for the tool in ArcGIS Pro and got the same results. I'm using ArcGIS Pro 2.8 and ArcMap 10.7.1

Answer 1

Looking at your screen shots it appears that they have different Polygon Grid Origin Coordinate values. I suspect ArcGIS Pro is defining the origin based upon the coordinate system so the origin is way off the map as you view it because that is where it is. Or its defining them based upon a featureclass extent which is much greater than the extent of the data, you can fix that type of error with Recalculate Feature Class Extent (Data Management) tool.

ArcMap looks to be defining the origin based upon the current map view extent or the extent of the data in the shapefile rather than the coordinate system extent.

That's my best guess.