An example of the correct format in WKT - taken from https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry - would be: MULTIPOLYGON (((30 20, 45 40, 10 40, 30 20)), ((15 5, 40 10, 10 20, 5 10, 15 5)))
The implementation of the land cover mapping services should accept the multi-polygon format, although this is to be verified. The implementation uses the Orfeo Toolbox.
However, thanks to your message we noted an issue on the platform, which currently prevents using the MULTIPOLYGON format in connection with uploading reference data. A fix for this issue is now planned for the next platform update.
Meanwhile, you should be able to proceed by specifying the outer extents of the data with POLYGON. This only links the data to a geographical area for the purpose of reference data search on the platform, so this does not need to be exact. In actual processing, the land cover mapping service will read the contents of the Shapefile to determine the specific (multipolygon) area to be used. I hope this helps.
-Renne / Forestry TEP
Yes I already used these format for multiple polygon, but doesn't work.
I try with outer extents and with POLYGON but doesn't work.
I may have misunderstood your point. My above explanation was for uploading the reference data to the platform: the requierd "geometry", i.e. the geographical extents of the data, is specified in WKT format with POLYGON(...). The purpose is to enable locating the data on the platform, and does not need to be precise.
However, in the Land cover mapping services, the format and content of the reference data is significant: it needs to be in Shapefile format, which allows specifying the training data features in multiple polygons. Please refer to the tutorials for LandCoverS2 and LandCoverS1 for specific explanation. I hope this answers your question.