Forum: WebMapViewer Forum

Issue with multiple Coordinate Reference System (CRSs) and Layers

Hi all,
I have some issues with the customization of the Web Map Viewer on the test portal:

Configuration and user mode

    1. In order to use 3 CRSs for my service (the default equirectangular projection (EPSG:4326) and two polar stereographic projection (EPSG:32661 and EPSG:32761)), I added two CRSs to WMV from tab n°11 of the configurator but I noticed that there aren't default WMS layers for the added CRSs (north and south) and the relative visualization is empty. So I added some external test layers here because I don't have enought information to use the OGC Search. These layers are correctly shown on the WMV only in the configuration page; in the Search page, the map wiev is empty (white) although the layers are present into the "Layer Manager" and the the "eyes" are opened. Moreover only the Search results get correctly displayed.
    2. I tried to set up different layer for different CRSs changing each time the default CRS, but every time I save and change CRS, the previous lose informations. To permit the coexistence of north and south pole layers, I had to add all layers to default view (EPSG:4326).
    3. Another issue is that when I change two or more times the CRS into the Search page, the default layers get unexplicably deleted and "GTOP030 elevation model (WMS)" and "Bathymetry Model (ETOPO2) (WMS)" appear.

Any suggestion?

Documentation lacuna

    1. I read the online documentation and in the "note" of this paragraph it seems to be possible to change layers for only one CRS.
    2. To change the actual CRS to another one there is the "CRS" button at the end of the "Layer Manager". I noticed that this is not mentioned in the offcial documentation.

Thanks and regards

Re: Issue with multiple Coordinate Reference System (CRSs) and Layers

Thank you very much!



Re: Issue with multiple Coordinate Reference System (CRSs) and Layers


The default context files for the UPS N and UPS S are now available on both portals.

Best regards,

Re: Issue with multiple Coordinate Reference System (CRSs) and Layers


In fact, if the WebMapViewer at portal level gets configured with appropriate web map context files for each CRS, the behaviour will be like this. Upon swith of CRS, the webmapviewer loads the layers of the context for that CRS.

What you suggest would be quite slow and would also be difficult to implement in a robust manner.

If you have WMS layers for the CRS that you are interested in (and they are publicly accessible), generate WebMap Context files for them (using the save button in the layer manager) and send them to me for validation and inclusion on the SSE.


Re: Issue with multiple Coordinate Reference System (CRSs) and Layers

Thanks, I'll wait for the new projections configuration.

I resolved the issue of WMV "User mode" by deleting all layers and adding only a few ATLAS layers valid for both EPSG:4326 and EPSG:32661.

In the meantime I would use the JS function addLayer to add, at each switch of CRS, the correct WMS Layer if there exists an event like onCrsChange that notifies a change in CRS, passing the new CRS selected by the user. With that kind of event, I could use every kind of CRS projection by configuring only the default one then changing the layers on CRS change, putting addLayer into the event handler. Could it be a good way of handling the issue?
If the above is feasible I'll also need to know which WMS layers you use in the SSE portal to display the default maps and their parameters.


Re: Issue with multiple Coordinate Reference System (CRSs) and Layers


1. a. The WebMapViewer does support different map layer configurations for different CRS (at Portal level) but this has not been configured for all hundreds of possible CRS. I'll ask the SSE team to add the files for the UPS N and UPS S projections.

1.b. If you start the Viewer in "User mode", the Viewer will zoom to the Bounding Box of all features (AOI, Service Results, ...) that are present within your map configuration. In configuration mode, you will by default look at the maximum extent of the CRS. In user mode, check the extent that you are looking at and ensure that for the extent and scale that you are looking at, the WMS servers that you are using are able to show information.

2. You can only define a CRS at WebMapViewer level, not at WMS layer level. The WebMapViewer will check whether your CRS choice is supported for all WMS layers that you have previously added to your configuration. You can indeed only combine the Atlas of the Cryosphere layers for the North and South Pole, by bringing them together in one Viewer configuration with a CRS that is supported by both sets of layers. Note however that when you switch CRS, all layers that do not support the CRS will be removed from your context.

3. When switching CRS, the WebMapViewer removes all WMS layers that do not support this CRS. As the North Pole layers, do not support the UPS S projection and vice versa, you will only end up with a set of default background layers for EPSG:4326.

The original document is available at