DXF Import

PatGPatG Global Mapper UserPosts: 54Trusted User
edited July 2008 in Bug Report
We generate Maps using Microstation v8 and convert to DXF for client delivery if they don't use Microstation themselves.

We have noticed that we can import the DGN into GlobalMapper but converting to another format(such as Shapefile) we tend to lose alot more structure than if we import the DXF and convert.

We have noticed however that some DXF files (particularly 3D polylines and complex shapes) will be imported into GloballMapper and entities are broken and displayed in scattered and incorrect locations. This makes conversion using GlobalMapper impossible unless there is some way of identifying the entities causing this issue

I have attached a zip file containing the original DGN file, The DXF file for import and the Globall Mapper exported DXF and Shape files clearly showing the scattered entities...

I have tried with DXF versions 11/12 and 2005 with the same results

Any advice on how to prevent this would be most welcome....

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2008
    Pat,

    I have taken a look and I do see the misplaced lines when I pull in the DXF file. I will take a look and see if I can discover the cause of these errors.

    However, the DGN files (in particular the v8 DGN file) seem to pull into Global Mapper just fine. Anything that you see in Global Mapper export as is to a new format. What type of structure are you losing when you export from the loaded DGN file into a Shapefile that you are not losing when using DXF?

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2008
    Pat,

    I can't seem to find anything wrong with the decoding of the DXF file features that are out of position in your files, although obviously something is not being done right in Global Mapper as some other DXF applications correctly place the data. My only thought is there is something to do with the extrusion vector that these features seem to have which results in a much more complex transformation being required to get the coordinates into a usable form.

    In general I tend to hate the DXF format as it was not designed specifically for mapping data and thus has a lot of extra chunk that is not well documented. Occasionally files like these for which a few pieces are mysteriously misplaced turn up, but so far I have been unable to determine why they are misplaced.

    Hopefully we can get this worked out through the DGN end of things as that format is preferable, at least to me.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • PatGPatG Global Mapper User Posts: 54Trusted User
    edited July 2008
    Mike,
    Thanks for the quick response, the DGN does export everything in the correct location but I lose all colours and it tends to use the DGN level numbers for the new format level structure or coding. I have not yet found a way to use level names which is what we use for feature codes although I have not really had the time to test GM out properly.

    Is there a way in GM to change the way it imports the DGN file structure?

    Cheers,

    Pat
  • PatGPatG Global Mapper User Posts: 54Trusted User
    edited July 2008
    Mike,
    I appreciate what you are saying and I agree that the DXF format is now very cumbersome. Unfortunately it seems to be the one most supported by CAD/Mapping applications at least historically. Everybody and his dog is/was able to work with it due the fact that it is an ASCII readable format.

    I believe that GM should be able to at least import the DXF data spatially correct (I have tried converting our DGN to a DXF ver 11/12 format but this also did not pull in spatially correct) so I hope that it gets resolved at some point.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2008
    Pat,

    I would expect you to lose the colors when exporting from any format to Shapefiles as the Shapefile format does not have any standard way of storing style information. If you first export to a format like Simple ASCII Text File, then load that back in and export that to a Shapefile, you will be able to store some style attributes that Global Mapper will recognize for each feature.

    I agree that the DXF data should be read in spatially correct, but I have pulled my hair out on those few files that have just some pieces not placed spatially correct and have been completely unable to determine why those pieces don't fit where they should whereas other pieces that don't see any different at all fit perfectly.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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