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I am trying to export a QGIS_2.4 project to OpenLayers using the "Export to OpenLayers" plugin. I cannot export a raster layer. I am not getting any error message, but the raster layer doesn't appear in the preview window.

I have followed all rules in the plugin web page. Export to OpenLayers

Raster layers: They will be exported to JPEG files and reprojected into the default projection of the OL3 map to create (as EPSG:3857). The symbology is not used, so the layer must be a rendered image already. You can use the QGIS Save as rendered image functionality to get such an image from your data and symbology.

Any idea of what I am missing?

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I'm afraid the plugin is currently rather experimental.

Loading the start page directly fails for me in Firefox because of security issues when loading file:/// adresses. If I place the files in a folder that I can access with my local Apache server as http://localhost, I get the start page working.

It is then able to display OSM background and vector layers.

Raster layers should be converted to jpg by the plugin, but I don't find that jpg in the folder it should be. I reprojected the raster layer using QGIS to EPSG:3857, converted it myself to jpg using GIMP and put it in the layers subfolder. It then appears in the browser as expected.

If I have a WMS service in my QGIS project that can serve EPSG:3857, the plugin creates an OL file that hangs up before displaying anything because of missing quotation marks around the url. This can be fixed manually in layers/layers.js:

var lyr_DLM = new ol.layer.Tile({
                        source: new ol.source.TileWMS(({
                          url: "http://www.wms.nrw.de/geobasis/wms_nw_dlm50",
                          params: {"LAYERS": "nw_dlm50", "TILED": "true"},
                        })),
                        title: "DLM50"
                      });

The quotation marks after the url: were missing, everything else was written by the plugin. This may not work if the WMS server does not support EPSG:3857, or tiled WMS.

  • Yes i noticed that no jpeg file is created. How you convert the file to jpg so as it is still georeferenced? – Παύλος Αποστόλου Oct 10 '14 at 18:33
  • The jpg needs no georeferencing. That information is written into the layers.js file. But you have to use Raster->Translate from EPSG:2100 to EPSG:3857 and a new name before starting the plugin. – AndreJ Oct 10 '14 at 18:49
  • Thanks!!!!!!! Raster works fine. Can you please tell me the syntax for the wms? Where to put the quotation marks in the layers.js? – Παύλος Αποστόλου Oct 10 '14 at 19:13
  • See my extended answer. But I doubt that the WMS you mentioned supports EPSG:3857. – AndreJ Oct 11 '14 at 4:36
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    QGIS can reproject the WMS internally from 4326 to 3857, but openlayers can not. – AndreJ Oct 11 '14 at 14:31

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