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.
[GIS] How to convert 3tm to lat-lon
convert
Related Solutions
The easiest way is to go to the TOC table of contents...
right click the data frame (usually named layers).
Select properties. and the coordinate system tab.
then find the gcs system you would like to have as the final output
set the "document " to that by OK'ing out of the dialogs.
Then when you right click on the layer you want re-projected and select >Data
export data.
You get the export dialog.
Select the "same as data frame" option..
Give it a location and you are done.
There's another page on the GeoScience Australia website at http://www.ga.gov.au/scientific-topics/positioning-navigation/geodesy/geodetic-techniques/calculation-methods#heading-4 which contains a link to an Excel file.
If you download this file, then un-hide rows 8-39, you may be able to unpick their formula and apply it in your app.
Best Answer
gdaltransform will work, I must've just missed you on irc. I assume that 3tm is the projection here:
http://spatialreference.org/ref/epsg/3776/
to convert to WGS84 longitude/latitude:
gdaltransform -s_srs epsg:3776 -t_srs epsg:4326
Then type in your coordinates.