# [Proj] convert from LatLong to transverse mercator LUREF

Oscar van Vlijmen ovv at hetnet.nl
Wed Oct 19 09:18:00 EDT 2005

```>>>> I would like to convert geodetic
>>>> coordinates to a transverse mercator projection for Luxembourg.
>>>> I have the following coordinates:
>>>> Latitude: 49d34'17".60287N
>>>> Longitude: 5d55'50".69323E
>>>> And want to convert them into:
>>>> X (North) 70910.00
>>>> Y (East)  62935.00
>>> cs2cs +proj=latlong +ellps=intl +to +proj=tmerc +x_0=80000 +y_0=100000
>>> +lon_0=6d10 +lat_0=49d50 +ellps=intl +k=1
>>> 5d55'50.69 49d34'17.60
>>> 62934.93        70909.91 0.00
>>> Seems like pretty good agreement.
>> I can't believe PROJ or cs2cs are that inaccurate!
> Huh,  What inaccuracy ???
.....
> \$ cs2cs +proj=latlong +ellps=intl +to +proj=tmerc +x_0=80000 +y_0=100000
> +lon_0=6d10 +lat_0=49d50 +ellps=intl +k=1
> 5d55'50.69323 49d34'17.60287
> 62935.00        70910.00 0.00

Aaahh! Now I get it.
Mr. Warmerdam didn't use the requested coordinates but dropped decimals.
With his lon,lat of 5d55'50.69 49d34'17.60 I also arrive at:
x = 70909.9114859589, y = 62934.934921184 (not all decimals are significant)

Mr. Vine mentioned datum transform params for the Luxemburg grid.
For those who need them, ESRI-ArcGIS gives one or two more decimals in:
"Supported geographic (datum) transformations"