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I've got a CSV file which I downloaded from a Waka Kotahi open data website.

The file has got X,Y coordinates of locations. I am using that file in Python to generate markers in Folium. I don't have ArcGIS or QGIS.

Coordinates that file contains does not look in EPSG:4326 format. I suspect that it could be NZTM coordinate system (i.e. EPSG:2193). Because value looks like (X=1406914, y= 4915023).

Is there anyway that I could find the coordinate system of coordinates without using GIS system?

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  • @mikewatt thanks. Last question: Do you know any website that converts coordinates into EPSG4326? I want to convert lat:-40.9006 long:174.8860 into EPSG4326 Nov 3 at 20:03
  • Your coordinates look like EPSG:4326 but you seem to know that they are in some other coordinate system. What is that?
    – user30184
    Nov 3 at 20:11
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    Can you download QGIS? It would make your life easier if you're working with gis data. Convert coords here epsg.io/transform#s_srs=4326&t_srs=3857 just change the coordinate systems to the ones you need.
    – jbalk
    Nov 3 at 20:27
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    As a rule, it's better to get the spatial reference from the data provider than trying to guess, mostly because guessing has such a high error rate.
    – Vince
    Nov 3 at 20:40
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If you download the shapefile instead of the CSV you'll find a .prj file in the zip which is the projection metadata:

PROJCS["NZGD_2000_New_Zealand_Transverse_Mercator",GEOGCS["GCS_NZGD_2000",DATUM["D_NZGD_2000",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM[
"Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",1600000.0],PARAMETER["False_Northin
g",10000000.0],PARAMETER["Central_Meridian",173.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]

If the next step in your processing can deal with the WKT format like this, then great!

Otherwise QGIS recognises that as EPSG:2193 - NZGD2000 / New Zealand Transverse Mercator 2000 so you can plug that EPSG code into a conversion process.

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