Using version 0.5.96 on Windows.
When saving an existing map which has motorway (symbol 501.2) on it as an OCD file, then reloading the file, the Motorway symbol is no longer there - instead, there are two new symbols in the symbol set - one 501.2 and one 501.3. One of them contains the inner line only, the other the rest of the symbol definition. In the map, visually the motorway is still there but it is now split into two objects, using one of each symbol.
When saving the same map as omap, there is no such issue.
It only happens when saving as an OCD file and reopening the same file (note - opening with OCAD also shows this separation).
This is not a bug.
The way some symbols such as 501.2 Motorway are constructed in Mapper cannot generally be exported to OCD symbols. Splitting the symbol and duplication the objects is the only way to maintain the map's appearance.
(There might be corner cases which could get away without the split.)
Thank you for the explanation.
I note that the there are several other modifications to the symbol set after import/export between the OCD9->OOM->OCD9. Most don't seem to affect usability like this split.
I did find a workaround which in my limited testing seems to work - only if one has the original OCD file, which I put here for others should they need it.
1.) Keep the original OCD file (if one started with one)
2.) After completing work in OOM, open the exported OCD file in OCD
3.) Load the Symbol set from the original OCD file, overwriting the symbol set in the new OCD file
That's the basic workaround, indeed. I suppose it will also restore color definitions.
Note that this probably won't remove the duplicate objects.
Please remember that Mapper does not claim to be a full editor for OCD files. It has got import and export, but some features of OCD files are not supported.
I hope I find the time to implement my idea of preserving unmodified OCD color and symbol definitions...
As an additional note, in the OCD 8 symbol set that I have the fill color in road symbols is represented twice (because the "fill" setting is activated and the "framing" settings are used to produce the same line again). In this case it should be possible to safely disable one of the lines, which should avoid the duplication.
Mapper has a more general way of representing multiple lines in a symbol. Theoretically it would of course be possible to check on export whether such a symbol can be represented by a single OCD symbol and export it in the same way as it has been imported.