I'm unable to find out a formula for converting 3tm coordinates to lat-lon? 3tm is a system used in Alberta alone, as far as I can tell. The city of Calgary uses that for its opendata, which is what I'm trying to process.

1 Answer 1


gdaltransform will work, I must've just missed you on irc. I assume that 3tm is the projection here:


to convert to WGS84 longitude/latitude:

gdaltransform -s_srs epsg:3776 -t_srs epsg:4326

Then type in your coordinates.

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