I want to create a raster surface representing the flood level in a creek based on output from a 1D hydraulic model.
I receive a 3D profile of the water surface in a creek line as a 3D Polyline (AutoCad format) from our hydraulic modelers. Each vertex of the polyline represents the coordinates and level of the water surface based on cross-sections used in the modelling.
I want to import the string into QGIS and generate a water surface as a raster for analysis - for example depths, extents, comparison of flood level to building floor levels, etc).
Basically I want to extend a surface horizontally and perpendicular from the string until it intersects a nominated raster surface (existing ground), along the length of the string. I would assume that the elevation varies linearly between each vertex of the polyline (which would be accurate enough for my work).
Is there a way to generate this surface in QGIS? I would appreciate any guidance.
PS I have edited this question to hopefully make it clearer.