ERROR 4: Unable to open EPSG support file gcs.csv.

[RTC]

Our app is getting this error since updating to 100.15.4 SDK for iOS.  How can we resolve this issues?

ERROR 4: Unable to open EPSG support file gcs.csv.  Try setting the GDAL_DATA environment variable to point to the directory containing EPSG csv files.

[Ting]

Please visit https://developers.arcgis.com/ios/downloads/#projection-engine-data to download the projection engine data, and see gdaldata folder inside. It should contain the gcs.csv file.

This change happened a few releases back, though I cannot pin down the exact time (some time around 2021).

Read more about spatial reference and projection in this doc.

There is a related sample "List transformations" that you may take a look at.

Let me know if you have other questions.

[RTC]

Thank you for the info!

[RTC]

The download is about 2GB, zipped. Do I only need the gcs.csv file for the app?

[Ting · Accepted solution]

I'm not an expert on projection systems, but I guess it depends on what type of projection transformation you need. For instance, if you don't use NADCON or NTV2 transformations, you can delete their folders from the pedata.

A huge chunk of data is in the vertical coordinate system's transformation folder, so check with your client on what type of transformation they need.

When a transformation is removed, it will set the Boolean isMissingProjectionEngineFiles to true.

[RTC]

OK thanks Ting!  I will find out which transformations are being used by our client and remove the rest.

[Ting]

You're welcome! If later on you have problem figuring out what are the essential files for a specific transformation, I can pass along this question to our coordinate system folks.