Importing shapefiles from arcgis

Hi all!

So for the moment I am unable to correctly import shapefiles in GM 18, as when I do it it tells me that the .shp file doesn't have projection informations even if it's in the same folder with the related .prj file. If I try to add the projection infos in the subsequent menu then it says the .prj doesn't contain such informations.

What happens next is that it loads the file, usually super tiny and with an incorrect projection. Even If i try to manually change the coordinate system etc it doesn't seem to change in any way.

Someone has ideas on that?

Thanks!
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Best Answer

  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,948
    Answer ✓
    Hello Pietro,

    I think the problem is that you are using an Equirectangular projection, when the data is in Geographic (Latitude/Longitude). The Titan datum does not appear to be supported in Global Mapper 18. Did you add it yourself? If so, I suggest that when you load the data, select the Geographic (Latitude/Longitude) projection along with the your Titan datum.

    Note that Global Mapper 20 supports the Titan datum. You can download Global Mapper 20 and request a trial license, to see if your data gets loaded correctly.

    Cheers,
    Bob


Answers

  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,948
    Hello Pietro,

    By default, Global Mapper is looking for a .prj file with a name that matches the shapefile name (for example, roads.shp and roads.prj.) If your .prj has a different name, you should be able to load it on the window that asks for the projection infomation, but you are getting an error. It might be helpful if you can make a zip file that contains your shapefile and the .prj, and post it here.

    Cheers,
    Bob
  • Pietro_MPietro_M Posts: 9
    Here are all the related files,

    Thanks!
  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,948
    edited February 6
    Hello,

    I was able to load the file successfully in Global Mapper 20.  Here is the metadata:
    FILENAME=P:\Customer Data\Pietro\Fluvial_ChannelsCopy.shp
    DESCRIPTION=Fluvial_ChannelsCopy.shp
    AREA COUNT=0
    LINE COUNT=431
    LINE VERTEX COUNT=8416
    POINT COUNT=0
    MESH COUNT=0
    LINE SPATIAL INDEX=List size: 431, Nodes: 61, Depth: 5, Memory: 27,348 bytes, Items by Level: 1|6|53|308|78, Max Idx Count: 31
    UPPER LEFT X=-147.3169596360
    UPPER LEFT Y=2.7840594010
    LOWER RIGHT X=-116.0741421280
    LOWER RIGHT Y=-20.6698616980
    WEST LONGITUDE=147° 19' 01.0547" W
    NORTH LATITUDE=2° 47' 02.6138" N
    EAST LONGITUDE=116° 04' 26.9117" W
    SOUTH LATITUDE=20° 40' 11.5021" S
    UL CORNER LONGITUDE=147° 19' 01.0547" W
    UL CORNER LATITUDE=2° 47' 02.6138" N
    UR CORNER LONGITUDE=116° 04' 26.9117" W
    UR CORNER LATITUDE=2° 47' 02.6138" N
    LR CORNER LONGITUDE=116° 04' 26.9117" W
    LR CORNER LATITUDE=20° 40' 11.5021" S
    LL CORNER LONGITUDE=147° 19' 01.0547" W
    LL CORNER LATITUDE=20° 40' 11.5021" S
    PROJ_DESC=Geographic (Latitude/Longitude) / TITAN / arc degrees
    PROJ_DATUM=Interplanetary, Titan
    PROJ_UNITS=arc degrees
    COVERED AREA=1462059 sq km
    CODE_PAGE=65001 (UTF-8)
    LOAD TIME=211.36 s
    FILE_CREATION_TIME=2/6/2019 1:04:05 PM
    FILE_MODIFIED_TIME=2/4/2019 3:23:52 PM
    The datum appears to be related to Titan, one of the moons of Saturn, so it is not surprising that the location on Earth in Global Mapper might not be right. Is this what you expected? I don't think this datum is available in Global Mapper 18, which is why the PRJ file could not be loaded.

    Cheers,
    Bob

  • Pietro_MPietro_M Posts: 9
    Actually I've loaded others files using this PROJ_DATUM=Interplanetary, Titan and they work perfectly in terms of projection and everything else (raster files).

    I am able as well to load it in GM, but the projection and scale is completely odd compared to the mentioned raster files.

    Yeah that datum for Titan is surprisingly implemented in GM 18, I aslo tried to create my own datum copying from ArcGIS but nothing changes.

    Cheers,
    Pietro
  • Pietro_MPietro_M Posts: 9
    FILENAME=F:\PIETRO\Pietro_Titan\Pietro_Titan Mapping\data\SHP2\Fluvial_ChannelsCopy.shp
    DESCRIPTION=Fluvial_ChannelsCopy.shp
    AREA COUNT=0
    LINE COUNT=431
    LINE VERTEX COUNT=8416
    POINT COUNT=0
    MESH COUNT=0
    UPPER LEFT X=-147.317
    UPPER LEFT Y=2.784
    LOWER RIGHT X=-116.074
    LOWER RIGHT Y=-20.670
    WEST LONGITUDE=179° 59' 48.1995" E
    NORTH LATITUDE=0° 00' 00.2230" N
    EAST LONGITUDE=179° 59' 50.7021" E
    SOUTH LATITUDE=0° 00' 01.6557" S
    UL CORNER LONGITUDE=179° 59' 48.1995" E
    UL CORNER LATITUDE=0° 00' 00.2230" N
    UR CORNER LONGITUDE=179° 59' 50.7021" E
    UR CORNER LATITUDE=0° 00' 00.2230" N
    LR CORNER LONGITUDE=179° 59' 50.7021" E
    LR CORNER LATITUDE=0° 00' 01.6557" S
    LL CORNER LONGITUDE=179° 59' 48.1995" E
    LL CORNER LATITUDE=0° 00' 01.6557" S
    PROJ_DESC=Equirectangular / Titan / meters
    PROJ_DATUM=Titan
    PROJ_UNITS=meters
    COVERED AREA=0.000733 sq km
    CODE_PAGE=65001 (UTF-8)
    LOAD TIME=0.02 s

    here are the metadata for the same file

    I see differences in PROJ_DESC with my units in  meters while yours are in arc degrees


  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,948
    Hello Pietro,

    As far as I can tell, the latitude and longitude coordinates in the shapefile match what I see on the screen in Global Mapper. Where on the earth do you expect the data to be located?

    Does the metadata that you provided represent the correct location? The projection in your metadata (Equirectangular) is not the same as what is provided in the PRJ file that you uploaded here (Latitude/Longitude). Are you sure that you have the right coordinate system when you export from ArcGIS?

    Cheers,
    Bob
  • Pietro_MPietro_M Posts: 9
    As far as I can tell, the latitude and longitude coordinates in the shapefile match what I see on the screen in Global Mapper. Where on the earth do you expect the data to be located?
    Actually I'm working on Titan's geomorphology so the coordinates are perfectly fine.

    Does the metadata that you provided represent the correct location? The projection in your metadata (Equirectangular) is not the same as what is provided in the PRJ file that you uploaded here (Latitude/Longitude). Are you sure that you have the right coordinate system when you export from ArcGIS?
    Actually the file is the same one that I gave you, so this looks bizarre. Anyway I am quite sure that I have the right coordinates system since I've succesfully uploaded several Titan's raster files and they are all projected as expected.

    I think is a shapefile problem, as I tried also with others without success.

    Thank you very much for your time Bob,

    Cheers,

    Pietro
  • Hi Bob,

    Do you maybe have some other suggestions?

    Thanks,

    Pietro
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