# UTM to lat/lon .grd file **URL:** \ **Category:** Q&A\ **Created:** [June 22, 2020, 5:20pm UTC](https://forum.generic-mapping-tools.org/t/utm-to-lat-lon-grd-file/569 "2020-06-22T17:20:11Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![BaileyAtlas](https://avatars.discourse-cdn.com/v4/letter/b/aca169/32.png) [@BaileyAtlas](https://forum.generic-mapping-tools.org/u/BaileyAtlas)\ **Post date:** [June 22, 2020, 5:20pm UTC](https://forum.generic-mapping-tools.org/t/utm-to-lat-lon-grd-file/569/1 "2020-06-22T17:20:11Z")
Hi, all. I am new to GMT and am having trouble with the mapproject and grdproject commands to transform UTM to Lat/Lon in a grid file. I believe I am entering everything correctly but I’ve only been using GMT for about 2 weeks so I’m still learning. I have a UTM grid file in zone 27N and here is how I have tried entering the command: gmt grdproject eyjafjardarall\_s\_utm27\_10mEIK.grd -Ju+27 -I -GSouth\_Eyjafjardarall\_latlon.grd gmt mapproject eyjafjardarall\_s\_utm27\_10mEIK.grd -Ju+27 -C -I -F Each time it generates a file but the file is not the correct lat/lon ☹ Does anyone have some guidance for me on what I’m doing wrong/how I should be going about it? Thank you! ---
**Author:** ![Joaquim](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/joaquim/32/16_2.png) [@Joaquim](https://forum.generic-mapping-tools.org/u/Joaquim)\ **Post date:** [June 24, 2020, 11:40am UTC](https://forum.generic-mapping-tools.org/t/utm-to-lat-lon-grd-file/569/2 "2020-06-24T11:40:58Z")
> [@BaileyAtlas](#): > > gmt grdproject eyjafjardarall\_s\_utm27\_10mEIK.grd -Ju+27 -I > -GSouth\_Eyjafjardarall\_latlon.grd > > gmt mapproject eyjafjardarall\_s\_utm27\_10mEIK.grd -Ju+27 -C -I -F `mapproject` is for vector data. It could never work with grids. Try ```auto gmt grdproject eyjafjardarall_s_utm27_10mEIK.grd -Ju+27/1:1 -I -C -F -GSouth_Eyjafjardarall_latlon.grd ```