WaSP Map Editor with negative contours (2008-07-10)

[Old Forum Archivist]

I've been trying to load a map into Wasp's map editor. This map is of an area in Kazakhstan on the shore of the Caspian sea which lies at 27m BELOW sea level, so my minimum Z=-27m.



When I open the map, the map editor reports that there are curves with invalid or missing properties.



If I manually edit the map in AutoCAD and move all of the contours up by 30m such that the minimum Z value is 3m then the map can be loaded without generating the load errors.



This raises some questions:



1. Are the results produced in WaSP valid with this small elevation increase (+30m) over the whole map area?



2. If I use the maps with negative elevation contours in WaSP or WaSP engineering will this cause problems with the calculations?

--------

If you are not in a place below the level of the sea, the contourn map should not mark lines or height negative values of the region. If this happens, you should do the following thing:

1) open as a copy the DWG file and convert every contourn line of the region to a single layer (only one layer for the entire region)

2) erase any other layer that does not contain contour lines, including objects containing layers or any other element



3) proceed to convert the DWG copy of the file to the DXF file that map editor needs to work



4) if a message says to you that there are missing contourn lines, check the map image to verifyng corrected heigth values



good luck

--------

[MarkHerskind]

Hi.. I have the same problem.. I'm working an area near the dead sea, which surface is almost 400m below sea level, hence the Z-values are negative.. I can manually and artificially raise the level, so that everything is above sea level.. But I think the editor (and WASP/WENG included) should be able to support this.. An idea could be to replace the STOP with a warning instead, if you are worried people will do simulations without checking their map..

/Mark

[Ole Rathmann]

Hi all - the rejection of maps with negative elevations in the Map Editor was just introduced as a reaction to elevation outliers. The WAsP flow model can easily cope with negative elevations; it is the relative variation of terrain height that matters, not the absolute value.

We will modify the Map Editor so it only reacts to extremely negative and positive elevations (say,<-10 000 m and >+10 000m)