How to ignore "handle bad layers" in QGIS?

Question

I have a QGIS (2.14.3-Essen) project that I use both at work and at home. I keep all but two layers with the project.

The two remaining layers are very large - a DEM and hillshade totaling more than 20 GB - and they are stored in different paths at work vs. home.

I would like to ignore the Handle Bad Layers dialogue and keep the broken paths for those layers. I often don't care they are bad; I want to make changes to other parts of the project.

Is there a way to do so, to ignore or skip the Handle Bad Layers dialogue so I don't lose the reference to the layers if I don't update them?

Answer 1

A possible work around would be to modify your qgs project file using a script. I found that if you replace the datasource with <datasource>.</datsource> then it will ignore the Handle Bad Layers pop up.

Python script to run if you don't want to load certain layers.

import fileinput

replaceNextLine = False

for line in fileinput.input('path\to\your\project.qgs', inplace=True):
    if replaceNextLine:
        print '<datasource>.</datasource>'
        replaceNextLine = False
    else:
        print line,

    if '<id>layer_name_whos_datasource_needs_to_change' in line:
        replaceNextLine = True

Python script to run to insert the appropriate datasource path.

import fileinput

replaceNextLine = False

for line in fileinput.input('path\to\your\project.qgs', inplace=True):
    if replaceNextLine:
        print '<datasource>.\path\to\your\datasource</datasource>'
        replaceNextLine = False
    else:
        print line,

    if '<id>layer_name_whos_datasource_needs_to_change' in line:
        replaceNextLine = True

Doing this you could set up a DoNotLoad.py with the top script and a home.py with paths to your home sources and a work.py with paths to your work sources using the second script as a pattern.

You will then have a single project to work on but you can easily change your paths depending on the environment you are in, or change the paths so that the layers are not loaded, but are still in your project (all of your styling is saved and I think you can even modify the styling if you want. Just nothing will show up in the map).

Answer 2

Just make separate copies from your project file for home and work use.

Data you save will be written to the layer source files, not to the project file.

Once you have finished the homework part, you can take it to work and re-add the bad layers. If you have a difficult styling on layers, you might save it separately and add it too.

---

Another choice is to wrap a VRT file around the external source.

A sample example for a Geotif raster file, created with gdal_translate:

<VRTDataset rasterXSize="1656" rasterYSize="846">
  <GeoTransform> 2.0005201224994706e+005, 6.2653333397239589e+002, 0.0000000000000000e+000, 6.9906275735481549e+006, 0.0000000000000000e+000,-6.2653333397239589e+002</GeoTransform>
  <Metadata>
    <MDI key="TIFFTAG_RESOLUTIONUNIT">2 (pixels/inch)</MDI>
    <MDI key="TIFFTAG_XRESOLUTION">120</MDI>
    <MDI key="TIFFTAG_YRESOLUTION">120</MDI>
  </Metadata>
  <VRTRasterBand dataType="Byte" band="1">
    <ColorInterp>Red</ColorInterp>
    <SimpleSource>
      <SourceFilename relativeToVRT="1">testtif.tif</SourceFilename>
      <SourceBand>1</SourceBand>
      <SourceProperties RasterXSize="1656" RasterYSize="846" DataType="Byte" BlockXSize="1656" BlockYSize="1" />
      <SrcRect xOff="0" yOff="0" xSize="1656" ySize="846" />
      <DstRect xOff="0" yOff="0" xSize="1656" ySize="846" />
    </SimpleSource>
  </VRTRasterBand>
</VRTDataset>

and a sample for a shapefile:

<OGRVRTDataSource>
    <OGRVRTLayer name="testshp">
        <SrcDataSource>F:\Karten\vrt\testshp.shp</SrcDataSource>
            <SrcLayer>testshp</SrcLayer>
            <GeometryType>wkbPolygon</GeometryType>
            <LayerSRS>EPSG:31466</LayerSRS>
    </OGRVRTLayer>
</OGRVRTDataSource>

When the source files are not present, the raster is displayed as a black square (you might turn the layer to invisible), and the vector layer becomes a non-geometry table, without any error messages. Additional non-vrt layers with source files that are not removed will stay and can be edited. If you reinstall the source files, everything is back to normal, even the changes to the other layers.

Answer 3

The ChangeDataSource plugin keeps the layers in the file by moving them temporarily to a handle bad layers group. https://geogear.wordpress.com/2016/01/29/changedatasourceplugin-plugin-release-2-0/ It should do what you want. Last year I was having a similar issue and noticed that there was the ChangeDataSource plugin that worked with layers but did not handle bad layers. I mentioned that handling bad layers would be a great feature in the comments on the developer's (Enrico Ferreguti) blog. Within a week he had added it!