After Importing DGM in RasMapper Terrain is dislocated

[Anonymous]

Hey Guys,

first sorry for my bad english…
….after importing my digital terrain modell (as GeoTIFF) in RasMapper the Terrain seems to be dislocated (about 6 m to the north). This will cause that the computed inudation boundary and the water surface elevetion are dislocated. In addition the terrain in the cross section editor do not fit with the geometry.
Now I checked the position of the terrain in QGIS. The Terrain is on the right place, everything ok.
Than I checked the projection of the terrain and the projection I set in RasMapper. Every projection is “gauss krüger Zone 3”. Than I deleted the terrain from HecRas and imported it again….and again….and again. The problem still existing now…
Is there anyone who had the same problem before or can give me a tip so I could try to solve the problem?

I would be very grateful.

Greetings

Ela

[Anonymous]

Hello,
Does anybody get the same problem ?
I do.
Does anybody get the answer ?
Thanks

Marie

[Anonymous]

your coordinate systems are off that is the only answer

[Anonymous]

Hello,
What do you mean by “your coordinate systems are off” ?
My system is “WGS 84 / UTM zone 33n “.
I try several time but there is still an offset according to the south direction (it seems to be only according y axe).
I test an other thing :
– I cut my DTM according to the expected flooding area instead of the entire DTM
– Result : the terrain on HECRAS was still translating according to the south direction but in a smaller proportion.
I don’t understand why !! 😮

Thanks for your answer,

Marie

[LorenAmelang]

I just noticed your report. Sounds a bit like mine:
http://hec-ras-help.1091112.n5.nabble.com/Terrain-from-EPSG-3310-file-is-475-south-of-Web-Imagery-tp6257.html

The terrain I had pre-processed and re-projected in QGIS was displaced. RAS Mapper (from 5.0.5) was able to import the original DEM directly – in the correct location.

See also:
http://hec-ras-help.1091112.n5.nabble.com/Terrain-layer-not-aligned-with-other-layers-td6130.html#a6354

Looks like a real bug somewhere between QGIS and RAS Mapper. They aren’t kidding about “BETA”! The Release Notes ask for reports, but I’ve received no acknowledgement for sending them…

[benp]

Problem solved here with square pixel instead of rectangular.
http://hec-ras-help.1091112.n5.nabble.com/Problem-with-misaligned-spatial-projection-prj-British-National-Grid-td3753.html#nonehttp://
I don’t know if this solve your problem.

[Author]

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