displaying features BENEATH the elevation model
jbartlett79@gmail.com
Global Mapper User
Hello all - I've learned to do most of what I'm looking for in this program, and I know I'm only scratching the surface. Primarily what I am looking to do is create representations of limestone caves as they relate to the surface topography above them.
Anyway, so I have my DEMs loaded, and my 24k topo quads laid on top, anti-aliased and texture mapped to the elevation models beneath. I've exported a shapefile with elevation data from the cave survey program. In the attached screenshot I've left the topos at 100% transparency (opaque), but originally had planned to leave them around 50% so the 3D view would see through them and into the "hillside" below.
The problem, here, is that even with the shapefile set to "draw first" in the file heirarchy, the software is placing the shapefile atop the other layers (basically discarding the elevation figures), and it's texture mapping to the elevation models which is incorrect.
I'd presumed that the elevation data in the shapefile would function in conjunction with the elevation model, placing the cave passages at the appropriate depth beneath the topography. Is this something that can be done? It seems that the software is not allowing the shapefile to exist BENEATH the surface of the DEM, and plastering it along the surface is just putting each point at the lowest available place.
Help!
Jeff
PS - I have intentionally (and crudely) obscured several names from the screenshot; this is a private cave and a rather fragile one, and unfortunately the spring it feeds is labeled plainly on the USGS topo... information I'd prefer not be made available on the internet!
Anyway, so I have my DEMs loaded, and my 24k topo quads laid on top, anti-aliased and texture mapped to the elevation models beneath. I've exported a shapefile with elevation data from the cave survey program. In the attached screenshot I've left the topos at 100% transparency (opaque), but originally had planned to leave them around 50% so the 3D view would see through them and into the "hillside" below.
The problem, here, is that even with the shapefile set to "draw first" in the file heirarchy, the software is placing the shapefile atop the other layers (basically discarding the elevation figures), and it's texture mapping to the elevation models which is incorrect.
I'd presumed that the elevation data in the shapefile would function in conjunction with the elevation model, placing the cave passages at the appropriate depth beneath the topography. Is this something that can be done? It seems that the software is not allowing the shapefile to exist BENEATH the surface of the DEM, and plastering it along the surface is just putting each point at the lowest available place.
Help!
Jeff
PS - I have intentionally (and crudely) obscured several names from the screenshot; this is a private cave and a rather fragile one, and unfortunately the spring it feeds is labeled plainly on the USGS topo... information I'd prefer not be made available on the internet!
Comments
-
Jeff,
You've unfortunately hit one of the limitations of Global Mapper. The 3D viewer only supports displaying a single terrain surface (created from the top-most gridded elevation value at each location in the display), and any rendered display is draped on top of that. It does not currently support displaying 3D vector features in space above or below the surface.
Let me know if I can be of further assistance.
Thanks,
Mike
Global Mapper Support
support@globalmapper.com
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