Hi Patine,
Again you have to be careful, Empire is really just 40 tiles wide by 98 high. If you look at the very first row of the east -west tiles you will see that they increment by 2 as well (0,0), (2, 0), (4,0). Whereas the 2nd row below it goes (1, 1), (3,1), (5,1), etc. But count the first or second row tiles from left to right and you will see that there are only 40.
In any case, as a future reference, if you need the exact same map size as a specific scenario you can open the scenario in ToT, go to the Map - Toggle Cheat Mode menu and choose 'Yes ' when asked if you want to enable cheat mode.
From there go back to the Map menu and select 'Export Map' and a Save Map window will open.
Then just name your file (with the .MP extension) and select the Windows Explorer folder you want to save it in.
Then close ToT and open the civmap.exe and go to the Editor - Load Map menu and load the map from the folder you saved it in. From there you can modify the map as you like.
Note: Right now I'm limited in the MapEditor to a map size no greater than the sum of 10880 tiles (width x height). I believe there's a programs that allows you to exceed that number but I can't recall where it is.
In the meantime, here is the Empire map I extracted. Let me know if this is what you were looking for.