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I have a shapefile with coordinates in the "EPSG:3081 NAD83 / Texas State Mapping System" coordinate system. I'd like to be able to convert these to EPSG:4326 WGS 84 and it's not clear how.

https://epsg.io/transform calls https://epsg.io/trans?x=1137180.95833637&y=958229.501643337&s_srs=3081&t_srs=4326 via AJAX and I tried calling that with a for each of the 1,000+ coordinates that I have but it seems like that URL throttles requests.

Hans Erren
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neubert
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  • I'm no expert but since the link you provide list the coor transform in x and y you couldn't just apply it directly to the data? Never had to do manual conversions but that seems simple enough to test. – Al rl Jun 10 '22 at 22:11
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    If there's a EPSG code for it, it doesn't seem all that esoteric to me. It's perfectly reasonable that epsg.io would rate-limit their server -- It's their server after all. Since there are so many other tools that support deprojection with transform, it doesn't seem like this is really any challenge. – Vince Jun 11 '22 at 01:11
  • Since 3081 is available in QGIS it should be possible with QGIS unless I am missing the point – M Dollinger Jun 11 '22 at 02:09
  • @Alrl - you don't just multiply the latitude and longitude by some constant value to get the new latitude / longitude in a new coordinate system. If it was that easy then maybe you should reply to https://gis.stackexchange.com/a/325551/17847 – neubert Jun 11 '22 at 02:20
  • @MDollinger - I'll have to check that out - I didn't know QGIS could do that. – neubert Jun 11 '22 at 02:21
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    you can also use ogr2ogr from the command line to change the projection. This article explains how. – Llaves Jun 11 '22 at 03:26
  • @Llaves - that's awesome - I didn't know that - thanks! That was the most convenient as I was already using ogr2ogr to do the import. – neubert Jun 11 '22 at 03:32
  • This question already had something similar if you wanted to do it manually https://gis.stackexchange.com/questions/133861/converting-between-wgs84-and-nad83 – Al rl Jun 11 '22 at 11:17

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The EPSG:3081 NAD83 / Texas State Mapping System is supported by MyGeodata Cloud Converter so you can upload your Shapefile there, set EPSG:3081 as input coordinate system (if it is not recognized automatically), select output coordinate system to EPSG:4326 WGS 84 and choose output format - you can leave ESRI Shapefile or for example extract coordinates to CSV file...

Tonny
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