Export GIS data to RAS

[cuba28]

Hello,

I’ve a problem with the export of the GIS layers to HEC-RAS. The export is done but when I verified the cross sections, the elevations are not exported correctly from the DEM ! Could anyone help me please ?

Regards

[user]

Is your elevations correct before exporting ? You could view your cross section before exporting it . Another note is make sure you digitise your cross section left to right facing downstream .

[cuba28]

Thanks for your response Sir.

The elevations are correct before exporting, I even checked the cross sections profiles before exporting them, they are correct. Also, the cross sections have been digitized correctly, from left to right in the direction of the flow. So, what’s the problem then ?

[user]

Did you try exporting the cross section one by one and see whether do they align nicely?

[cuba28]

Actually, the cross sections are correct, the only issue is the value of the elevations. They are like if we’ve introduced a scale factor

[user]

If thats the case , you should use the datum adjustment in HEC-RAS to correct the elevations manually. Normally you should able to obtain the same cross section before and after export.

[cuba28]

Yes, I really don’t understand the problem. Using the datum adjustment manually takes a long time, because I’ve many cross sections and many points for each cross section, and the adjustment is different for each point, it’s not homogeneous…

[Author]

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