0

I am trying to load a DEM (img file + prj file) into QGIS 3.12.1 and use it as a layer over OpenStreetMap. However, I can't seem to get the CRS right, the OTF-conversion does not show the layer on the map.

I am using EPSG:3857 as project default and the read CRS from the prj file with OTF CRS conversion enabled:

PROJCS[
    "Transverse_Mercator",
    GEOGCS["GCS_Geographic Coordinate System",DATUM["D_MGI",SPHEROID["Bessel_1841",6377397.155,299.1528131060786]],
    PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],
    PROJECTION["Transverse_Mercator"],PARAMETER["scale_factor",1],
    PARAMETER["central_meridian",10.33333333333333],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",-5000000],
    UNIT["Meter",1]
]

How can I transform this CRS to EPSG:3857?

Here are the files I am trying to load: https://vogis.cnv.at/geodaten/?service=files&t=418171be46e40175bfe171edfc4097dd&path=%2FGelaendemodelle%2FHoehenmodelle%2FVlbg_Umgebung

0

1 Answer 1

2

It looks like MGI / Austria GK West (EPSG:31254) or MGI / Austria GK M28 (EPSG:31257), no other tmerc projection has lon_0 at 10.333333 in proj EPSG file. From the epsg file (/usr/share/proj/epsg on Linux):

...
# MGI (Ferro) / Austria GK West Zone
<31251> +proj=tmerc +lat_0=0 +lon_0=28 +k=1 +x_0=0 +y_0=-5000000 +ellps=bessel +towgs84=682,-203,480,0,0,0,0 +pm=ferro +units=m +no_defs  <>
...
# MGI / Austria GK M28
<31257> +proj=tmerc +lat_0=0 +lon_0=10.33333333333333 +k=1 +x_0=150000 +y_0=-5000000 +datum=hermannskogel +units=m +no_defs  <>
...

I downloaded your smaller file gtxxxx_25m and opened in QGIS and changed the unknown projection to EPSG:31254 and added to OSM standard layer. Here is the result, it looks good.

enter image description here

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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