[Therion] Google Earth terrain model

[Stelios Zacharias]

2 cents from Greece:

What I do is take the SRTM dats from NASA, pass them through vtopo's 
"gensur" stand-alone programme which makes a text file with height 
data for whichever part of the inputted SRTM file interests you.

Then I take this to Therion and convert the header text of the .sur 
file into the Therion format:

#Surface   231.836    235.996     0.080   53    3909.144    3915.084 
   0.090   67

grid       231836     3909144    80    90    53    67

Above, the header of the .sur file is placed above the grid line of 
the Therion file.


The first 2 numbers are the UTM beginning and end of the data in Km 
on the X-axis. Only the first number needs to be turned into m 
(multiply by 1000) and put as the first figure on the Therion line.

The third number is the spacing of the info: 0.080 (Km) meaning that 
the points are 80m apart on the x axis. This becomes the third figure 
in the Therion format.

The fourth number is the number of entries, or the size of the grid 
on the X axis. This number is placed as the fifth figure in the 
Therion format.

The fifth and sixth are the limits of the data on the Y axis - again, 
only the beginning is interesting to us and it is multiplied by 1000 
and placed as the second figure in the Therion format.

The seventh number is the spacing of the info: 0.090 (Km) meaning 
that the points are 90m apart on the Y axis. This becomes the fourth 
figure in the Therion format.

The eighth number is the number of entries, or the size of the grid 
on the Y axis. This number is placed as the sixth figure in the Therion format.



To do this is just as complex as it sounds, and you need to keep your 
wits about you when selecting the limits of the gensur export from 
the SRTM data. I usually keep the gensur header in the Therion file 
with a hash for reality-checks as necessary.

Cheers,
Stelios


At 11:53 08/07/2009, you wrote:
>Is there a way to (easily) extract terrain model data from Google 
>Earth in a format that can be used by Therion / Loch?
>
>
>Bruce
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