# Mapproject (gmt6): EPSG 2180 conversion issue

**URL:** <https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528>\
**Category:** Q&A\
**Created:** [December 8, 2022, 8:19pm UTC](https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528 "2022-12-08T20:19:19Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mvanneste](https://avatars.discourse-cdn.com/v4/letter/m/e79b87/32.png) [@mvanneste](https://forum.generic-mapping-tools.org/u/mvanneste)\
**Post date:** [December 8, 2022, 8:19pm UTC](https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528/1 "2022-12-08T20:19:19Z")

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All,  
I have difficulty projecting data into EPSG 2180 ([https://epsg.io/2180](https://epsg.io/2180)), which I understand to be a transverse mercator, CM 19°, and false easting/northing of 500000/-5300000. Hence, I thought the following syntax should work (using ELLIPSOID GRS-80).

echo “16.9166666667 54.866666667” |   
gmt mapproject -F -Jt19/0/1:0.9993 -R15/17/54/55 -C500000/-5300000  
which results in:  
366247.09 784376.38

However, using proj gives me a different result:  
echo “16.9166666667 54.866666667” |   
proj +proj=tmerc +lat\_0=0 +lon\_0=19 +k=0.9993 +x\_0=500000 +y\_0=-5300000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no\_defs +type=crs  
366340.72 780117.32

The latter is the correct one, it seems.  
What am I doing wrong with mapproject?

Thanks in advance,  
Maarten

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<div class="post-metadata">

**Author:** ![pwessel](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/pwessel/32/30_2.png) [@pwessel](https://forum.generic-mapping-tools.org/u/pwessel)\
**Post date:** [December 8, 2022, 8:34pm UTC](https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528/2 "2022-12-08T20:34:25Z")

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Think you mean

**echo 16.9166666667 54.866666667 | gmt mapproject -F -Jt19/0/1:1 -R15/17/54/55 -C500000/-5300000 --PROJ\_SCALE\_FACTOR=0.9993**

**366340.720034 780117.320116**

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<div class="post-metadata">

**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:** [December 8, 2022, 8:35pm UTC](https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528/3 "2022-12-08T20:35:08Z")

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or

```auto
echo 16.9166666667 54.866666667 | gmt mapproject -J2180
366340.720033 780117.319413

```

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<div class="post-metadata">

**Author:** ![mvanneste](https://avatars.discourse-cdn.com/v4/letter/m/e79b87/32.png) [@mvanneste](https://forum.generic-mapping-tools.org/u/mvanneste)\
**Post date:** [December 8, 2022, 9:08pm UTC](https://forum.generic-mapping-tools.org/t/mapproject-gmt6-epsg-2180-conversion-issue/3528/4 "2022-12-08T21:08:52Z")

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I see, I particularly like the last one, where we can use the EPSG code. I was not aware of that.  
Many thanks for the swift response!  
Maarten