MapWindow Measuring Tool and curious NAD 83 State Plane Coordinate System inconsistencies in .prj files

I have been using MapWindow recently, and it seems like a very good program, especially considering it’s free. As my employer no longer provides a viewer to our customers, we have been recommending MapWindow…but…there is a problem. Many of our customers use the California State Plane Coordinate System with units of U.S. feet and, for whatever reason, the measuring tool in the current version of MapWindow (4.8.6) doesn’t seem to be able to deal with feet. I started noodling around with shapefile projections in ArcMap, Global Mapper, and MapWindow and checking out the .prj files in Notepad to see if I could find any clues.

So, I created a shapefile and made a copy. I defined the projection of one in ArcMap, and of the other in MapWindow. Arc was able to display them both correctly, but did not recognize that the projection is actually the same. When I pulled both into MapWindow, the ESRI one failed to reproject and was not displayed. When I opened both in Global Mapper, no problem. So then I exported a new one from Global Mapper, and tried opening all three simultaneously in MapWindow. MapWindow displayed the Global Mapper and MapWindow ones, but again the ESRI one failed. All three open fine simultaneously in both ArcMap and Global Mapper, but the addition of the MapWindow defined layer triggers a warning that it has a different geographic coordinate system than the other two.

A peek at the projection information illuminates that there is some inconsistency in how even the datum is described:

From MapWindow:

NAD83 / California zone 5 (ftUS)
Projection: Lambert_Conformal_Conic
false_easting: 6561666.667000
false_northing: 1640416.667000
central_meridian: -118.000000
standard_parallel_1: 35.466667
standard_parallel_2: 34.033333
latitude_of_origin: 33.500000

Linear Unit: US survey foot
NAD83Datum: North_American_Datum_1983

From ArcGIS:

NAD_1983_StatePlane_California_V_FIPS_0405_Feet
Projection: Lambert_Conformal_Conic
False_Easting: 6561666.666667
False_Northing: 1640416.666667
Central_Meridian: -118.000000
Standard_Parallel_1: 34.033333
Standard_Parallel_2: 35.466667
Latitude_Of_Origin: 33.500000

Linear Unit: Foot_US
GCS_North_American_1983Datum: D_North_American_1983

From Global Mapper:

NAD83_California_Zone_5_ft
Projection: Lambert_Conformal_Conic
false_easting: 6561666.666667
false_northing: 1640416.666667
central_meridian: -118.000000
standard_parallel_1: 34.033333
standard_parallel_2: 35.466667
scale_factor: 1.000000
latitude_of_origin: 33.500000
Linear Unit: Foot_US

GCS_Geographic Coordinate System
Datum: D_NORTH_AMERICAN_1983

Shouldn’t this kind of thing be standardized?

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