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Contours (again?)

Mapper
2015-12-07
2016-05-26
  • Roland Roberts

    Roland Roberts - 2015-12-07

    I read the post about using QGIS to create contours by creating a DXF file. So...I took my shape file, which loads just fine into QGIS and tried exporting as a DXF. I suppose this is at least as much a question about QGIS and OOM, but I'll start asking here.

    There are a few options on the export dialog dealing with symbology mode, symbology scale, and character set encoding. I set character set encoding to ISO8859-1, and tried all three options for symbology mode (none, feature, symbol layer), and a scale of 1:10,000. In all cases, the resulting DXF file can't be imported. The error is "This file is not a DXF file".

    So...any suggestions for a tool that can create an importable contour for OOM?

     
  • Roland Roberts

    Roland Roberts - 2015-12-07

    Actually, I left out one part...that original post about using QGIS has the cryptic remark about georectifying the exported DXF. I should start with the question: how does one do that?

     
  • Roland Roberts

    Roland Roberts - 2015-12-08

    If nothing else, I supposed I can try to create a template that has the contours in it and then print with the templates showing. And since the JPEG2000 issue is fixed in source, I can build from source and avoid having to load lots of little files.

    I'm just wondering if there is a better way.

     
  • Kai Pastor

    Kai Pastor - 2015-12-09

    You don't need to rebuild from source only to use the JPEG 2000 feature: There are the -unstable packages for Windows and Linux. I'm not sure how it can help to avoid loads of little files.

    However, if the DXF file can't be imported, it also won't work as a template. The DXF support in Mapper is quite limited, and there are already many reported issues.

     
  • Roland Roberts

    Roland Roberts - 2015-12-09

    I wasn't able to load the jpeg file as a single file; I'll have to go back and look at why. That's why I split the larger jpeg 2000 file into 1000x1000 chunks. Having jpeg 2000 support in the package means I can load the single 5kx5k image.

    I was thinking of converting the contour to a jpeg image instead of dxf and then using it as a template. It sounds like there really isn't any other way to get contours on my map right now.

     
  • Kai Pastor

    Kai Pastor - 2015-12-09

    There is also http://openorienteering.github.io/apps/contourtrace/ but I can't help much with that.

     
  • Roland Roberts

    Roland Roberts - 2015-12-09

    I finally found a way that's not bad at all. Using gdal_contour, I can create both major and minor countour shape files that can be loaded into QGIS. QGIS can export those as GPX files which can be imported into OOM.

    If I load the minor contours first, I can just select the whole map and fill them in. By setting them up in separate parts, this end up not being pretty easy. But I can find a way to completely hide map parts, so I have to do this as a last step when I'm ready to save the result.

     
    • Kai Pastor

      Kai Pastor - 2015-12-10

      Merging the current (imported) part with an existing one is just selecting the right item from the Map menu.

      Having the import create a distinct part allows to easily select all objects from a single import and assign them a symbol. This should actually help you to deal with major and minor contours.

       
  • Roland Roberts

    Roland Roberts - 2015-12-10

    Thanks, I managed to figure out the parts before I saw this message and that feature is definitely a life saver for dealing with contours.

     
  • Anonymous

    Anonymous - 2016-05-26

    I noticed that QGIS adds two lines at the top of exported DFX files that are not present in other DXF files. Removing the two lines allow the QGIS generated files to imported into OOM..

     

    Last edit: Anonymous 2016-06-15