3d vertices for shapefiles

[dave hoeffgen]

Hi there,

Producing high density CVX terrain for a larger area using scenProc and OSM data I stumbled upon the followin problem:
Hydro polygons require 3d vertices as the water's elevation is taken into account just like AB_flattens.

With my data not having elevation entries I was wondering if there is a way to bake the third dimension into the vector polys from a raster DEM file.
Is that possible using GDAL or QGIS?

Thanks in advance for any help.

Regards,
Dave

 

[GaryGB]

Hi Dave:

I suspect that other GIS applications besides Global Mapper can also do what you describe, but IIRC that may require each vector hydro polygon to be selected manually one-after-another, and the elevation ("Z") value added manually or semi-autmatically to the existing Lon ("X") and Lat ("Y"), to yield a X,Y,Z type of vector SHP file.


Since we are likely performing these operations with a step-wise manual method either way, one could also perform this operation with the desired terrain mesh loaded at top priority in a FS flight session, Append the SHP file(s) into SBuilderX, and read the pertinent Altitude for the area to be enclosed by the hydro poly as described here:

http://www.fsdeveloper.com/forum/th...res-to-a-3d-terrain-model.436776/#post-738442


In your case, however, within the SBuilder work-flow, the altitude value can instead be added to all vertices of the selected hydro poly without manually editing each vertex individually ...as discussed in the linked example above.

After adding the altitude value globally to all vertices of your selected hydro poly(s), they can be compiled to individual CVX BGLs.

Those CVX BGLs can then be decompiled with CVX-Extractor to output SHP files with the desired X,Y,Z attributes for use with ScenProc and/or other FS scenery utilities.


Hope this work-flow might help you and/or others with this type of task.

GaryGB

 

[dave hoeffgen]

Hi Dave:

I suspect that other GIS applications besides Global Mapper can also do what you describe, but IIRC that may require each vector hydro polygon to be selected manually one-after-another, and the elevation ("Z") value added manually or semi-autmatically to the existing Lon ("X") and Lat ("Y"), to yield a X,Y,Z type of vector SHP file.


Since we are likely performing these operations with a step-wise manual method either way, one could also perform this operation with the desired terrain mesh loaded at top priority in a FS flight session, Append the SHP file(s) into SBuilderX, and read the pertinent Altitude for the area to be enclosed by the hydro poly as described here:

http://www.fsdeveloper.com/forum/th...res-to-a-3d-terrain-model.436776/#post-738442


In your case, however, within the SBuilder work-flow, the altitude value can instead be added to all vertices of the selected hydro poly without manually editing each vertex individually ...as discussed in the linked example above.

After adding the altitude value globally to all vertices of your selected hydro poly(s), they can be compiled to individual CVX BGLs.

Those CVX BGLs can then be decompiled with CVX-Extractor to output SHP files with the desired X,Y,Z attributes for use with ScenProc and/or other FS scenery utilities.


Hope this work-flow might help you and/or others with this type of task.

GaryGB

Thanks for the reply, anyway because of the huge amount of data I'm dealing with SBuilderX is not an option (arguments are starting with the file size, continuing with the amount of polys to fix and finishing with usage restrictions)
There must be an automatic way or I'll have to bake raster images for 10,000 square kilometers

 

[GaryGB]

That large of a task probably calls for one of Arno's or Dick's clever "For... loop" batch files with a GIS utility in CMD mode.


Although the GIS command line switches used may be different, perhaps a basic CMD mode batch file structure may be derived from:

http://www.fsdeveloper.com/forum/th...ns-from-geotiff-to-tiff-automatically.433707/


Good Luck !

GaryGB

 

[Timmo]

I did it in python and ArcGIS- Iterated through each polygon and found its first vertex* and then read the height from the DTM, then set all vertices Z values to that height.

* not the most best approach, but examining heights for all vertices and then finding the lowest was too computationally expensive at the time.

 

[dave hoeffgen]

I did it in python and ArcGIS- Iterated through each polygon and found its first vertex* and then read the height from the DTM, then set all vertices Z values to that height.

* not the most best approach, but examining heights for all vertices and then finding the lowest was too computationally expensive at the time.

Sounds interesting. Do you think this would also work if each vertex was given its individual z value from the DEM?
I will also have a look if such a script API exists for QGIS as well.