[MLB-WIRELESS] Elevation maps on BrisMesh site

[David Ashburner]

 >
> > I don't know what we have behind the loc finder but I assume there is a
> > rdbms somewhere there. Rather than pre-draw the images we could
> > pre-calculate and then render the appropriate data sets.
>
>The database just has lat/lon of very poor quality.
>
OK, so the locations of any node is only as good as the accuracy when it was 
entered and the height information is just as rough due to possible survey 
error.

In the map finder there are layers of data. Are the layers snipped out of a 
larger raster image or they   rendered from vector data?

>All you need to do with the srtm data is fine the two points that
>are at the end of the location and find the height of nearby grids
>along the direct line and that should give you a good idea.

Yep, that is what I was thinking. The question is really how is the data 
represented.  When a map is drawn the data set is reduced to the stuff that 
is visible, If  it is a series of lat/lon  with a height then and algo to 
detect intersection of the LOS line with each contour segment could work. If 
it is raster data - I give up.



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