[Therion] Creating GeoTIFF files

Andrew Atkinson andrew at wotcc.org.uk
Fri Jul 7 11:29:21 CEST 2023


Although not the answer to your question, another route is Patrick Warren's 3d to qgis (not arcgis) plug in

https://github.com/patrickbwarren/qgis3-survex-import

Andrew
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On 7 July 2023 08:25:40 BST, Xavier Robert <xavier.robert at univ-grenoble-alpes.fr> wrote:
>Hi Bill,
>
>I do not really understand why to export survey stations as a geotiff file (raster, image). Survey stations are points (vectors) and are more easier to manage through GIS softwares as shapefiles (vector format). This is the Therion ESRI output.
>
>In the ESRI output folder, you have several shapefiles in 2D (exported as map) and in 3D (exported as model): outline, areas, lines, areas, points, shots3d, stations3d (several files for each shapefile). 
>
>Stations3d contains all the stations of the survey… 
>The points shapefile should also contain the points station. See the attribut table associated to this file and use that to select the points you want to plot.
>
>
>For one of my main project, I wanted to produce a clean georeferenced map with :
>the survey with a rendering depending on the zoom used,
>at important zoom, the stations with their altitude, 
>and overlays as OSM, Geology, hillshade, altitude contours,…
>
>We used that in a QGIS project that we coupled with the Merging Maps app. This is still in development, but that permits to do field prospection with all the cave database and GPS positioning on your phone.
>     
>
>Unfortunately, the direct ESRI Therion output is not clean enough to produce such GIS maps. I needed to write Python scripts to :
>add the stations and entrances altitude as a new column in the attribute table,
>cut the lines and areas shapefiles to keep only what is inside the outline (expect for the option clip off); Before running this script, I often need to test the validity of the polygons shapefiles to make sure that they are valid… 
>We also make some svg symbols corresponding to symbols used by Therion, but this is not yet complete. (If someone has already a svg symbols library for therion shp, I am interested !)
>
>For those interested, this is now partially included in the Samoëns cave repository : https://github.com/robertxa/Topographies-Samoens_Folly (written mostly in French)
>To make the GIS files, I run the « SamoensGIS.thconfig ». After compiling Therion files, it calls Python scripts (edit the .thconfig to check if the lines are not commented) that are in Samoens-GIS/Scripts (https://github.com/robertxa/Topographies-Samoens_Folly/tree/master/Samoens-GIS/Scripts). The whole QGIS project is not uploaded on GitHub as some files are to big for Github. But I can share it on demand.
>
>For now, this is still a bit dirty (and still dedicated to this project, you will need numerous changes to apply it to an other project), I am still working on this. If you try it, if you miss a specific file, if you have any questions or suggestions/improvements, etc. do not hesitate to contact me !
>
>Cheers,
>
>Xavier
>
>
>> Le 7 juil. 2023 à 02:01, Bill Gee <bgee at campercaver.net> a écrit :
>> 
>> A question has come up from one of my caver friends who is very new to cave survey but an old hand at ArcGIS and various other ESRI tools.  He earns a living as a GIS expert.
>> 
>> He would like to get a georeferenced TIFF (GeoTIFF) which includes GPS coordinates of survey stations.  I looked at the KML file produced by Therion and find no references to survey stations.  A KML file is really just a long (very long!) list of GPS coordinates, so it probably could include survey stations.
>> 
>> So my question for the group:  Is there a way to produce a GeoTIFF file which includes survey stations?
>> 
>> Related question:  Do the ESRI outputs from Therion include survey stations?
>> 
>> Thanks!
>> -- 
>> ===============
>> Bill Gee


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