Point feature to DEM

[arno]

Hi,

I have a shapefile containing points with elevation values. Does anybody know an easy way to convert this data into an elevation grid that I can process with resample?

 

[LCSims]

I don't know the scale of the project, but you could import the SHP file into SBuilderX, make sure the elevation data stays accurate and make a sloped poly from it. Using the SHP in a GIS tool I'm not sure of, unless you are looking to do some interpolation to fill areas in?

You didn't mention which sim, so my response relates to FSX.

 

[Timmo]

Im not sure if 3D interpolation and easy go in the same sentance The only way I know is inside GIS software (i.e ArcGIS) and even then I wouldn't call it simple

 

[GaryGB]

Hi Arno:

Is this data what might be referred to as a "multi-point Z Shapefile" ?

Global Mapper Version 11 for example, has added support for saving elevation values from multi-point Z Shapefiles (via a vector export function).

These files, when properly projected, may require further interpolation at a specified output gridding to render a complex data set suitable for a DEM.


Also, in Global Mapper, there is a way to process the data if it is from a contour layer shape file; then one can create a DEM.


DEMs created by either method can subsequently be converted to a GeoTiff:


http://pbisotopes.ess.sunysb.edu/reports/tvelia/Producing DEM in Global Mapper.pdf


Of course, the described workflow may also be achieved with another GIS application having comparable capabilities.


http://pbisotopes.ess.sunysb.edu/reports/tenzin.pdf


It might be a good idea to do as much "interpolation resampling" as possible in 3rd party GIS software prior to processing by FS SDK Resample; then one might wish to use the "FractionBits" parameter in the *.INF file to minimize "terracing" of contours as the elevation for one's mesh vertices are computed for output to the BGL.



Knowing a bit more about the precise type of shapefile structure you have might help determine what to do, and with what application, to render output into a format that FS Resample can process as a terrain mesh:


http://www.pcigeomatics.com/cgi-bin/pcihlp/GDB|Supported+File+Formats|Arc/Info+Shapefile+(SHP)



Alternatively, would I be correct that this is basically "X,Y,Z" (Lon/Lat/Elevation) data packaged in a *.SHP file format ?

If the SHP also file contains other data, normally one can "map" certain fields to extract the XYZ vector data for selective export processing in one's GIS app.


http://en.wikipedia.org/wiki/Shapefile


Hope this helps !

GaryGB

 

[arno]

Hi,

Thanks for the feedback. Since this shapefile contains around 3.8 million points, going for the manual approach is not really an option .

The shapefile I have is a shapefile containing point features. The altitude is stored in the attributes though (not sure if it is also written to the Z coordinate, but else that can always be changed).

What I am currently trying is to use QGIS to make a mesh out of these vertices using a Dalauny triangulation. From that mesh I could then be able to create a raster.

 

[Timmo]

Lidar Data?

Regardless of the package you use, you will likely spend a lot of time figuring out how to interpolate the data in a way that doesn't cause your computer to spit the dummy due to the sheer amount of it......I've done it within and ArcGIS environment but took a lot of work to split the points into tiles, interpolate then merge... reprojection from a projected to geographic coordinate system (i.e. WGS84) also caused problems with tiling.

 

[arno]

Lidar Data?

No, actually these are measurements made from the ground by normal surveyors.

Regardless of the package you use, you will likely spend a lot of time figuring out how to interpolate the data in a way that doesn't cause your computer to spit the dummy due to the sheer amount of it......I've done it within and ArcGIS environment but took a lot of work to split the points into tiles, interpolate then merge... reprojection from a projected to geographic coordinate system (i.e. WGS84) also caused problems with tiling.

I am about to come to the same conclusion, it is just too much data . Maybe it is easier to see if we can find some raster data, as it can be quite some work to do this conversion with good quality.

 

[BASys]

Hi Folks

Arno -
As the data is held in a dbf
a table manipulation should suffice.

EDIT
Scratch that, it's not relevant to your objective.

I'd used a filter to export a coastline.

EDIT 2
I'll do some digging,
but am sure I'd exported a mesh from a shapefile.
ISTR it was an GDAL/FWTools import.


HTH
ATB
Paul

 

[arno]

Hehe, thanks Paul. I was just about to reply and ask you want you meant .

 

[Whiskeyportal]

I'm a GIS mapper and I would suggest a program called Global Mapper http://www.globalmapper.com/?gclid=CLjLl7rXoZ8CFREMDQod_22hGw
It is a very handy tool for these kinds of files and offers many options for conversions and opens pretty much anything.