ARCHE maps dissemination service

Uses a mapserver to disseminate raster and vector ARCHE resources.

The mapserver is set up to:

• expose itself at http://{container ip}/cgi-bin/mapserv
• allow map config files only in the /data directory (subdirs can be used though)

The ARCHE dissemination service is set up to expose itself at http://{container ip}/?id={arche resource URI or ID}&{optional mapserver request parameters}.

The ARCHE dissemination service serves the request by:

• checking if the ARCHE resource is not cached locally and if not
  • download it into the /data/{md5 sum of the ARCHE resource URI}
  • creating a map config file for it in /data/{md5 sum of the ARCHE resource URI}.map
• redirecting to the mapserver

Deployment

On each GitHub release a Docker image is rebuild and redeployed on the ACDH-CH cluster using this GitHub Actions script.

Including static data

First of all, please consider if you need to publish your data using the mapserver service. If you have a raster file(s), then until you are forced to provide access to it over the WMS protocol (e.g. because you are bounded by the INSPIRE EU directive), you should be just fine with serving it as XYZ tiles (the protocol used by all web map services like Google Maps, Bing Maps or Open Street Maps and supported by all web map frameworks like Leaflet, Open Layers or Goole Map API). Generation of XYZ tiles pyramid is a matter of a single call to the gdal2tiles.py script and the resulting file structure can be published as static files. An example of doing the tiling inside a GitHub Workflow and publishing the tiles as a GitHub Page is provided by this repository. If you have questions or need help, please contact Mateusz Żółtak or Peter Andorfer.

If you still think you want to use the mapserver service, then static data can be added by extending this file and redeploying the service. This script is run just after the container startup. The data is downloaded after the container startup and not during the container build to avoid storing (potentially large amounts of) data inside the image.

Alternatively a share storing the static data can be mounted in the container under the /data directory or its subdirectory (see the redmine issue #22520).

Please remember you have to provide the map config files for your data. If you find the documentation linked above overwhelming, you can start with minimalistic-yet-useful templates used by the ARCHE dissemination service.