I have randomly distributed surface points from a Post Processed Kinematic GPS survey (accuracy ~10cm) and wish to calculate surface contours. The reason for doing this is to have detailed data for all the shakeholes. Would like to import the contours into Survex/Therion so these can be seen above the cave. Has anyone else done this and how ? My current thinking is to use the QGIS Contour tool to generate the contours and then import these into Survex/Therion as elevation strings using some intermediate data format yet to be decided. Thanks, Kevin
Hi Kevin, You could definitely use QGIS to do that, and probably export in a format close the the one used by Therion. I’m using directly GDAL command lines to convert in a format similar to the surface file for Therion, I can dig in my files to find the command line. But I don’t know if you can use directly the GDAL command lines with windows OS. Phil
On 14 Aug 2018, at 16:32 PM, kevin dixon via Therion <therion@speleo.sk> wrote:
I have randomly distributed surface points from a Post Processed Kinematic GPS survey (accuracy ~10cm) and wish to calculate surface contours. The reason for doing this is to have detailed data for all the shakeholes. Would like to import the contours into Survex/Therion so these can be seen above the cave.
Has anyone else done this and how ?
My current thinking is to use the QGIS Contour tool to generate the contours and then import these into Survex/Therion as elevation strings using some intermediate data format yet to be decided.
Thanks,
Kevin _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
Hi Kevin, I did that in a quite dirty way : from the contour lines, build a DEM that you export in an ArcGIS ASCII format Pass the ArcGIS format to the Therion format (header to change) In QGis, drap the contour lines over the DEM Export the result as an image add the image in the DEM in the therion format with the bitmap command (see the thbook) Cheers, Xav
Le 14 août 2018 à 09:32, kevin dixon via Therion <therion@speleo.sk> a écrit :
I have randomly distributed surface points from a Post Processed Kinematic GPS survey (accuracy ~10cm) and wish to calculate surface contours. The reason for doing this is to have detailed data for all the shakeholes. Would like to import the contours into Survex/Therion so these can be seen above the cave.
Has anyone else done this and how ?
My current thinking is to use the QGIS Contour tool to generate the contours and then import these into Survex/Therion as elevation strings using some intermediate data format yet to be decided.
Thanks,
Kevin
participants (3)
-
kevin dixon -
Philippe Vernant -
Xavier Robert