3

I recently was looking at a way of using GeoTIFF in AutoCAD 2015. I was looking at a way of specifying coordinate system using one of UTM projections. I didn't have much luck with that and I decided to try AutoCAD Map 3D 2017, there is an entire library of different coordinate systems including WGS84 UTM Zone 30N, the one I was interested in.

Now, let me explain my problem, I've got .tfw file that I generated using listgeo tool, here is the content of that file:

        4.9995042276
        0.0000000000
        0.0000000000
       -5.0003231419
    -9782.7177138953
  6572004.2399761314

I tried to use my GeoTIFF with ArcMap, QGIS and one more survey positioning package, all of them after specifying the right coordinate system place the GeoTIFF in the right geographical location apart from AutoCAD Map 3D.

When I specified the coordinate system and units in AutoCAD Map 3D, the entire GeoTIFF looks like it has been shifted a significant distance to the West.

I'm just wondering if AutoCAD Map 3D is drawing GeoTIFFs in a slightly different way or am I doing something completely wrong here?

Did anyone have any luck with using GeoTIFFs in Autodesk packages (Map 3d)? I'm worried that the .tfw file might have wrong values as in QGIS and that survey positioning package I didn't have to use that file and the software positioned GeoTIFF for me, when in AutoCAD Map 3D I actually have to place that file in the same directory as my GeoTIFF in order to be used but the x,y translation doesn't seem to be correct. Here is the output of gdalinfo:

Size is 3805, 3248
Coordinate System is:
PROJCS["Transverse Mercator",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",-2.716666666666667],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-9785.217466009140500,6572006.740137700900000)
Pixel Size = (4.999504227592880,-5.000323141986690)
Metadata:
  AREA_OR_POINT=Area
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
  TIFFTAG_XRESOLUTION=127
  TIFFTAG_YRESOLUTION=127
Image Structure Metadata:
  COMPRESSION=LZW
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (   -9785.217, 6572006.740) (  2d53'17.62"W, 59d15'47.69"N)
Lower Left  (   -9785.217, 6555765.691) (  2d53'15.00"W, 59d 7' 2.84"N)
Upper Right (    9237.896, 6572006.740) (  2d33'16.92"W, 59d15'47.73"N)
Lower Right (    9237.896, 6555765.691) (  2d33'19.40"W, 59d 7' 2.88"N)
Center      (    -273.661, 6563886.215) (  2d43'17.24"W, 59d11'25.67"N)

@Jens When I used my file in QGIS I didn't use any extra world files, just the geotif itself, however when I tried to load my file in AutoCAD Map 3D I had to use tfw file as without it I was asked to specify the offsets for my geotif image.

  • If you have QGIS then you have also GDAL command line tools available. What intormation gdalinfo is listing about your image? – user30184 May 19 '16 at 7:34
  • at first glance: (1) according to spatialreference.org/ref/epsg/32630/html it should be: central_meridian = -3 scale_factor = 0.9996 false_easting = 500000 (2) -9782 is not a valid x-coordinate for EPSG 32630. X should lie in the range of 0 to 166000. (3) Do you have a Geotif (= georeferencing stored in file header) or do you use a Worldfile? If you use both: does the header and the wordlfile have the same values? (4) I have no problems in AutoCAD Map 3D 2016 with GeoTIF. There are several ways to add a Geotiff to Map. I use FDO to add images to a map. – Jens May 19 '16 at 14:57
  • Gdalinfo report means that your image in not in any UTM zone. QGIS and others can interpret the projection right by utilizing the GeoTIFF tags. Your projection may be a user projection without any suitable EPSG code. Let's hope that AutoCAD has utility for defining user projections. – user30184 May 19 '16 at 17:38
  • If QGIS doesn't have any issues with placing the file in the right geographical location when using the correct coordinate system, can one use the information included in the file's header / geotiff tags in order to position the same file correctly in AutoCAD Map 3D? There must be a way of doing that by specyfing user defined coord. system, if not is there a way of exporting that geotiff from QGIS for example, with updated tfw information, so Autocad can read the correct values. – Chris May 20 '16 at 5:53
  • To define a custom coordinate system in AutoCAD Map 3D: use _mapcslibrary; duplicate WGS84 UTM Zone 30N; change the parameters and save as new custom coordinate system – Jens May 20 '16 at 6:41
1

I tried number of different things with my geotiff file, including the process of creating custom projection in Autocad to match the one used with that file but I haven't had any luck. I tried to save the raster with different coordinate system (UTM Zone 30N, WGS84) - that at least gave me a file where the insertion point in Autocad Map 3D was very close to the one I would expect but still few tens of meters away. I haven't got any db installed at the moment hence I can't really try any of FDOs, as I was hoping to use QGIS and load the data from it.

Below is the link to the file I'm struggling with at the moment. When using WGS84 UTM Zone 30N in QGIS, file works fine, what I trying to do is to load the same file in Autocad Map 3D using the same coordinate system.

https://www.dropbox.com/pri/get/test.TIF?_subject_uid=50818096&w=AABswIqxz2Hs_Lya3y3-FIrro3DhWCZpDlNKunWq9MClAg

  • Have yout tried to add the TIF via FDO? Display Manager > Data > Connect to Data. In left pane window, select Raster. In right pane select your TIF and check whether AutoCAD detects the corrordinate System. If not tell AutoCAD the coordinate System of your TIF: help.autodesk.com/view/MAP/2016/ENU/… – Jens May 24 '16 at 13:12
  • I tried that, AutoCAD Map 3D doesn't detect the coordinate system of the file. Without .tfw inserts it as a regular image. When I used .tfw file, using the details which I mentioned in my original question, AutoCAD Map 3D is able to stretch the raster accordingly but places it in the wrong place because of that insertion point, which has got the negative value instead of Eastings and Northings of one of the corners of the raster image. I'm not sure if this will work, but I'll try to stick the file into the database in QGIS and connect to it this way and see if that works any better. – Chris May 26 '16 at 7:14

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.