2

I am trying to identify the correct coordinate system for some data, with x and y expressed as (for example, data located roughly in the UAE): 6,220,199; 2,742,099

I haven't come across these 7-digit coordinate pairs before, however I note that when I use the identify tool to find coordinates in ArcMap or set the units for a data frame to meters, with the dataframe coordinate system in WGS84, I get similar coordinate pairs.

What projected coordinate system does ArcMap use to express WGS84 in meters when using these tools? As it seems like whatever this is, is the correct PCS for my data.

  • Determining the projected coordinate system for unknown data is one of the most difficult tasks, try contacting the custodian of the data and ask. If that isn't an option but you know where the data should be (United Arab Emirates?) you can have a stab at the most common projected coordinate systems for the area, starting with EPSG:32639 (WGS84 UTM zone 39 North), then the suggestions from epsg.io/… might get you the answer you need. Hint: you can use the search in the CRS dialog for the EPSG code to save having to scroll through. – Michael Stimson Jan 14 at 0:38
  • Thanks for that. I've had a crack at all the most common expected projections including UTM 39N and UTM 40N. Unfortunately that hasn't borne any fruit. Hence why I am trying to seek the answer to the question posed in the post, as those coordinates for 'WGS84 displayed in metres' (not UTM) in ArcMap seem to match - but it's not a PCS I can select. – malcoholic Jan 14 at 0:55
  • 2
    Have you tried Web Mercator (epsg 3857)? – FSimardGIS Jan 14 at 0:56
  • There's a few PCS based on WGS84 in the link on my comment, the only difference should be the false easting/northing making them local datums for UAE. This is not an uncommon practice, many official PCS differ slightly from UTM either to make the numbers small (like a local datum) or because UTM straddles a zone boundary (like NZTM). – Michael Stimson Jan 14 at 1:40
  • @FSimardGIS thank you! Problem solved. If you post as answer I'll mark it. – malcoholic Jan 14 at 3:01
2

Your coordinates look like they could be in WGS 1984 - Pseudo Mercator (Web Mercator, EPSG 3857. Web maps often use Web Mercator, so it is a likely candidate), or World Mercator (EPSG 3395). In both cases, your example point would fall near the UAE - Oman border. Check to see if one of these fit your data correctly.

Some tools like projfinder and epsg.io can help in finding unknown coordinate systems too.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.