This is OK and very quick.
This is not a direct alternative to s_region however: resulting contours are much larger, can't be included in a table. But we can either have precomputed MOC stored somewhere (for datasets?) or compute them on the fly when required.
• Then: test intersections with something else .
How do we do that? Is it scheduled under the Logical operations menu item in Aladin (currently not used)?- see example in next pages
Image above was drawn before the inversion of longitudes in s_region from Mars craters service, so they plot correctly (inverted both in original s_region and in Aladin)