I think I've asked about this several months ago but I'm still facing difficulties when expanding my map and I'm still unable to overcome them.
(http://i1241.photobucket.com/albums/gg502/LegendkxTx/simscr96_zps0ac17686.png)
What I want to ask is whether I can expand my map without having a gap after the expanding process.
Can I solve this problem by changing my config/settings?
Looks like a bug to me. I don't see any reason why this should be intentional, let alone configurable. But you have failed to report which version of Simutrans you are using. This might have been fixed in newer versions.
I remember seeing this bug long time ago, but tested now and I can't reproduce with r7252.
It maybe that if you had an old saved game the heights have been already set incorrectly at the border so still show the bug?
I'm using version 112.3 now and I've set my border to a suitable height level.
The biggest problem isn't the land but the sea. I can't maintain the sea level to the same depth as surroundings manually. (Please refer to the screenshots)
Screenshots for better understanding:
(http://i1241.photobucket.com/albums/gg502/LegendkxTx/simscr97_zps101eb1c9.png)
(http://i1241.photobucket.com/albums/gg502/LegendkxTx/simscr98_zps25f8a061.png)
If it was an old map, I would have expected the slope and the cliff to have been the other way around, but I've never played with map extension as player nor developer.
Yes, the sea level really doesn't follow its depth. I don't know this part of the code, maybe Markohs may find the problem?
The depth below the sea doesn't have any impact on gameplay, or does it? Apart from giving you a cheaper route for tunnels, I mean. So it's just a tiny visual problem.