This is what I hope to do with translate():
Column 1: Geotrace coordinates in original format
43.001847 4.9032711 0.0 40.188;43.001847 4.9032711 0.0 40.188;43.001847 4.9032711 0.0 40.188;43.001847 4.9032711 0.0 40.188;43.0018446 4.9032637 0.0
Column 2: Add kml labels with concat():
concat("Polygon><outerBoundaryIs<LinearRing<coordinates", ${column 1},"</coordinates</LinearRing</outerBoundaryIs</Polygon")
Column 3: use translate() to Change " " (blanc) to "," and change ";" to " " (blank);
translate("column 2"," ",","} and translate("column 2",";"," "}
Result column 3:
Polygon><outerBoundaryIs<LinearRing<coordinates43.001847,4.9032711,0.0,40.188 43.001847,4.9032711,0.0,40.188 43.001847,4.9032711,0.0,40.188 43.001847,4.9032711,0.0,40.188 43.001847,4.9032711,0.0,40.188</coordinates</LinearRing</outerBoundaryIs</Polygon
I think this should work. No reordering, no dropping of elements, just converting a set of blanc spaces to comma's and some ; to blanc spaces. It is a workaround to do this calculation in ODK collect in order to show them in Google Fusion (better would it be if you can just publish polygons to Google Fusion), but it will be a helpfull workaround I think. The only thing is that geotrace plots 2 extra columns after the coordinates (height and accuracy) while kml only has 1 (height). But with testing, this does not seem to be a problem if they are separated by a comma.
Now the only option is downloading with the new Briefcase version (with export to GeoJSON), which is great work and a great tool by the way. However, I would like to have all my data in Google Fusion, including polygons, on the fly. This could be a great work around.
The help and feedback of you both is very much appreciated. I don't know how long it will take to be incorporated and being downloadable in a new ODK version (I supose modifications need to be made in XLSforms and in Aggregate and in ODK Collect?).