1

I have a few hundred rows of data with sweref99 coordinates that I want to plot using Fusion Tables on Google Drive.

What formula can I use to convert the two columns of Sweref99 x and y coordinates?

All my Google results so far just makes me end up at converters, not any formulas, forcing me to manually convert every row.

  • SWEREF99 and WGS84 are often considered equivalent so you just have to find a robust ellipsoidal transverse Mercator algorithm. One place could be IOGP (EPSG) GN 7-2 pdf. Disclosure: I'm on the subcommittee that maintains it. – mkennedy Apr 29 '15 at 21:47
  • Is there maybe a way to make this algorithm more approachable? I'm not even sure if "robust" has a specific meaning in this context or if you just mean "good", and I can't find the phrase "ellipsoidal transverse Mercator algorithm" anywhere in the pdf. – Henrik Aug 31 '15 at 17:50
  • Yes, robust means good where good means 'supports an adequate range of longitudes at mid- to -high latitudes. Some transverse Mercator algorithms use series expansions in the calculations. if the series doesn't have enough terms, longitude calcs on inverse (from xy) start to not work at 8-9 degrees--less at higher latitudes. – mkennedy Aug 31 '15 at 17:54
3

You can use the Proj4 converter: http://trac.osgeo.org/proj/ Yes, it is a converter but you can convert bulk coordinates.

Create a simple text file (let's say sweref99.txt) with the coordinates, e.g.

606905.22 6970515.93
635765.54 7223101.41

In order to convert all coordinates from this file the command is like this:

cs2cs +init=epsg:3006 +no_defs +to +init=epsg:4326 +no_defs sweref99.txt

You just have to use the correct EPSG code for SWEREF99, this I don't know which one. You should find it here: Spatial Reference or epsg.io

  • from = spatialreference.org/ref/epsg/3006 (epsg projection 3006 - sweref99 tm) to = spatialreference.org/ref/epsg/wgs-84 (obvious one) – Remigijus Pankevičius Apr 29 '15 at 20:33
  • Thanks for the answer, sorry for being the slowest responder ever. I tried doing this and got a (fairly encouraging) error. "projection initialization failure. cause: no options found in 'init' file. program abnormally terminated." Do you know what might fix the problem? I've just followed the readme provided in the download and your and r.pankevicius instructions. – Henrik Aug 31 '15 at 17:39
  • You must define an environment variable called PROJ_LIB. As value put the folder name where the projection file epsg is stored – Wernfried Domscheit Aug 31 '15 at 20:28
  • That's what I do to get this error. I get another error message when i assign another value to PROJ_LIB: "projection initialization failure. cause: no system list, errno: 2", so I must be doing something right... Any ideas? – Henrik Sep 2 '15 at 9:30
  • Please open a new question with tag proj.4 where you describe the problem. Surely you will get an answer. – Wernfried Domscheit Sep 2 '15 at 9:33

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.