map - river causing mysterious CTD

[SirRethcir]

I did some tests.
Ok, it is not a problem of to many river tiles on the map, but to many river tiles on a particular area of the map.
If an area is too clustered with rivers it cause a CTD. However, its very hard to give exact values. (see below)

During my tests I scrolled with the keyboard only.
Plain map:
- all 'Black' (RGB: 10,10,10)
- 751x1000 (375x500 tiles)

Test 1
arrangement of rivers:

o    o    o
|    |    |
                 ....
o    o    o
|    |    |
   :
   :

- 4 tiles between rivers
- 74 rivers * 2 * 99 rows = 14652 river tiles on the map
-> no CTD

Test 2a
arrangement of rivers:

o    o    o
|    |    |
|    |    |     ....
|    |    |
   :
   :

- 74 rivers * 492 length = 36408 river tiles on the map
-> CTD

Test 2b
- 74 rivers * 198 length = 14652 river tiles on the map
-> CTD

Test 3a
- arrangement of rivers as in 2
- rivers with fords
- 74 rivers * 62 length = 4588 river tiles on the map
-> no CTD

Test 3b
- as 3a
- 74 rivers * 63 length = 4662 river tiles on the map
-> CTD

Test 3c
- as 3a
- rivers without fords
- 74 rivers * 62 length = 4588 river tiles on the map
-> CTD

Test 4a
arrangement of rivers:

o    o    o
|    |    |
|    |    |     ....
        :
        :
|____|____|
     |

- based on 3a
- length 62 -> 4588 river tiles on the map
-> no CTD

Test 4b
- as 4a
- length 63 -> 4662 river tiles on the map
-> CTD

Test 4c
- as 4a
- confluence +3 tiles -> 4662 river tiles on the map
-> CTD

Test 5
- two rows of 3a
-> 9176 river tiles on the map
-> CTD

Test 6a
- 3a + 2x an own river (a way longer than 62 tiles, with serveral tributary rivers)
-> CTD occurs only in that part of the map where 3a-rivers and my own river are adjacent to each other

Test 6b
- cross check to 6a -> 6a without 3a
-> no CTD


Test 7a
arrangement of river:

o     ____
|    |    |
|    |    |     ....
        :
        :
|____|    |____|

- 3a transformed to one big river
-> 74x4 tiles added -> 4884 river tiles on the map
-> CTD

Test 7b
- as 7a
- but transformed in such a way that no additional tiles are added
-> 4662 river tiles on the map
-> no CTD

Test 8
- as 2a
- only every 4th river kept
- 19 rivers + 492 length = 9348 river tiles on the map
-> no CTD