GDAL blurb

A simple java app that makes terrain models in less than a minute, designed for use with survex and therion.

Terrain Tool blurb

To create surface profiles, you can string together a series of regularly spaced fixed surface points from, either a gps overland trail (lat long elev), a series of points manually extracted from Google Earth, or generated with the help of http://www.gpsvisualizer.com/elevation

To use GPSVisualizer

1. export a kml model of your cave (or a simplified representation) with therion
2. Upload the kml file to the online GPSVisualizer tool and request plain text output (it will replace the cave elevations with ground surface elevations)
3. copy-paste the data back into therion as fixed stations
4. join the fixed stations with nosurvey legs

A hint at how to get all these fixed point into a form that looks like a survey centreline in therion…

 centreline 
 cs lat-long
 grade BCRA3

 walls off 
 mark temporary   
 flags surface 
 # station-names 4wd01 [] # to avoid name clashes if required

 fix 	1	-42.0001724	171.9024155	572.6
 fix 	2	-42.00020492	171.9022789	574.04
 fix 	3	-42.00021414	171.9021513	574.04
 fix 	4	-42.00026879	171.9020413	575.01
 fix 	5	-42.00030752	171.901925	575.01
 #thousands of these, they are decimal degrees and metres

 data nosurvey from to
 1	2
 2	3
 3	4
 4	5
 5	6
 6	7
 #thousands of these as well, a spreadsheet makes them easy to generate

 endcentreline

 #Then just select this survey along with your cave when processing