Excluding Autogen using Shapefile?

[Kelvin Richardson]

I have fully covered New Zealand in Vegetation and Buildings but I want to see if there is any way I can use a shapefile, for example, for roads for the country and then use this shapefile in Scenproc to exclude all autogen based on the shapefile polygons?

Arno, would there be a way to do this? I currently have some roads convered by vegetation. Maybe have an option to exclude/remove autogen a certain distance from the center of a line using a line shapre file or the same with a poly shapefile.

This would make such a difference to the look of the terrain.

My project for Entire New Zealand can be found/purchased at www.nzscenery.co.nz. There is information and screenshots for my project.

Thanks again in advance.

 

[arno]

Hi,

Yes, that is possible. There are two approaches.

For vegetation polygons you can use the SubtractFeature step. That way you can subtract the road polygon from the vegetation to make sure the roads stay clear. If your roads are a line you can use the ExtrudeLine step to turn them into polygons first.

For point features (library objects, single trees) you can also use the AddAttributeIfInside step to test if they are on the road polygon or not. If you then add an extra attribute you can later skip those features when generating the autogen.

 

[Kelvin Richardson]

Thanks, Arno. I will give it a try and come back if I have issues.

Thanks for your advise.

 

[Kelvin Richardson]

Hi Arno,

Seems I am having trouble removing Autogen from my vegetation polygon.

See my syntax below, it would be good if you could take a look and let me know any corrections.

I have one shapefile 2 unique ID's for each feature (road and track) roads_tracks.shp is a line shapefile.

t50_fid=trees
name_utf8=roads
name=tracks

#
IMPORTOGR|D:\TerrainProjectData\sourcefiles\Shapefiles\Test\native_test.shp|*|*|NOREPROJ
IMPORTOGR|D:\TerrainProjectData\sourcefiles\Shapefiles\Test\roads_tracks.shp|*|*|NOREPROJ
#
SplitGrid|AGN|*
#
ExtrudeLine|FTYPE=LINE;name_utf8=*|3|Polygons|road
ExtrudeLine|FTYPE=LINE;name=*|3|Polygons|track
#
SubtractFeatures|FTYPE=POLYGON;name_utf8=*|t50_fid=*|2|MINAREAPOLY
SubtractFeatures|FTYPE=POLYGON;name=*|t50_fid=*|2|MINAREAPOLY
#
CREATEAGNPOLYVEG|FTYPE=POLYGON;FROMFILE=native_test.shp|{f092dfb1-0c9d-4352-bd71-28ff9d95f52b}
EXPORTAGN|P3D v2|D:\TerrainProjectData\output\test

Thanks in advance.

Kelvin

 

[Kelvin Richardson]

Me again, just worked it out. Changed to this:
Not using tracks now but had to change around the ID's which now translates as removing roads (name_utf8) from trees (t50_fid)

#
IMPORTOGR|D:\TerrainProjectData\sourcefiles\Shapefiles\Test\native_test.shp|*|*|NOREPROJ
IMPORTOGR|D:\TerrainProjectData\sourcefiles\Shapefiles\Test\roads_tracks.shp|*|*|NOREPROJ
#
SplitGrid|AGN|*
#
ExtrudeLine|FTYPE=LINE;name_utf8=*|1.4|Polygons|road
#
SubtractFeatures|FTYPE=POLYGON;t50_fid=*|name_utf8=*|.85|MINAREAPOLY
#
CREATEAGNPOLYVEG|FTYPE=POLYGON;FROMFILE=native_test.shp|{f092dfb1-0c9d-4352-bd71-28ff9d95f52b}
#
EXPORTAGN|P3D v2|D:\TerrainProjectData\output\test

 

[arno]

You are not using your extruded lines at all. I would expect to find Polygons=road as the selector of the features you want to subtract from the vegetation.

 

[Kelvin Richardson]

The features in my shapefiles do not all have legible names. However, I have found a way to manage what I want, I am using geoprocessing tools in QGIS to create a difference layer from all my main vegetation layers which will essentially burn the roads right into the vegetation shapefiles, i will then use Scenproc to just process the shapefiles without any additional processing. I have tested and this is perfect.