Terrain mesh on US-Mexico border

[crushnik]

What do you do when your terrain mesh data only covers the United States, and Mexico becomes a gigantic hole with million-foot spikes at the border? USGS data does not include Mexico or Canada.

Above is the San Diego, Calif. region. In the lower-right corner should be Mexico. TMFViewer shows elevation in purple areas as -575. What can I put in my INF file so P3D's default scenery shows through, and my terrain mesh BGLs don't punch a hole in Mexico?

[Source]
Type=GeoTIFF
Layer=Elevation
NullValue = 0,0,0
SourceDir="."
SourceFile="n33w118.tif"
PixelIsPoint=0
ulxMap=-118.000555555555
ulyMap=33.0005555555552
xDim=9.25925925258432E-05
yDim=9.25925925258432E-05

[Destination]
DestDir="."
DestBaseFileName="n33w118"
FractionBits=3
LOD=4,12

 

[arno]

Hi,

What is the no data value in your source data? You need to configure that in the inf file, so that the sim now there is no data in certain areas.

 

[crushnik]

Hi,

What is the no data value in your source data? You need to configure that in the inf file, so that the sim now there is no data in certain areas.

Hello Arno, The purple areas from the TMFViewer image show up as "no data" when I examine the USGS source GeoTIFF file in QGIS. Black areas from QGIS (seen below) become white "0" elevations in TMFViewer. The white "no data" to the south and west of the black boundary becomes the purple -575.

EDIT: Something from the P3D SDK's entry on Null Value just made sense to me:
"Sample value for each channel indicating that there is no data in the current pixel. For imagery sources use a comma-separated list: red,green,blue,[,land/water[,blend]]. For all other sources use a single value."

I was thinking that since my source data was an image, then "NullVallue=0,0,0" was the way to go. But once I caught the bit about land/water blends, they might be meaning imagery files.

I tried resampling with "NullValue=255,255,255" which gave me basically the same result, but with the occasional strip of pixels along the boundary where "0" becomes "no data" that appear to look like a thin wall of Legos over a kilometer high.

 

[arno]

You would have to set the null value to -575 in this case. The elevation data has only one channel, so one value is enough.

 

[crushnik]

You would have to set the null value to -575 in this case. The elevation data has only one channel, so one value is enough.

That made my "0" ocean elevations also -575. Elevation data gets crazy on the last American pixel before the border: Wild swings from around +1000 to -1000 elevations. Still looking into this... I'm glad I flew close enough to the border to notice this. I didn't get close enough to Mexico to notice before, and I was just about to officially release the scenery.