Survex Terrain model problem
Hi I was experimenting with the .3d model exported from Therion to Survex. The Survex viewer (Aven) has an option to display the terrain too. When I go to View > Terrain I get an error "No coordinate system specified in survey data". In the Therion data there is a coordinate system specified, fixed station as well as terrain data and it is displayed in Lox. Has anyone seen this error or had success in showing the terrain in Survex? Vladimir
+++ Владимир Георгиев [2016-03-24 13:41 +0200]:
Hi
I was experimenting with the .3d model exported from Therion to Survex. The Survex viewer (Aven) has an option to display the terrain too. When I go to View > Terrain I get an error "No coordinate system specified in survey data".
A terrain model has co-ordinates in real-world space, so you cave needs to also be located in real-world space (not just arbitraty 0,0,0)
In the Therion data there is a coordinate system specified, fixed station as well as terrain data and it is displayed in Lox. Has anyone seen this error or had success in showing the terrain in Survex?
You need to add a *CS command to your data (co-ordinate system) to say what system is in use, and add a fixed-point (e.g. for the entrance) to say where in that space the cave is. http://survex.com/docs/manual/datafile.htm (look for *CS) Wookey -- Principal hats: Linaro, Debian, Wookware, ARM http://wookware.org/
Hmm, you seem to be talking about the original Survex data file. I see the format is similar to the .th files, but I meant producing a 3D file exported from Therion. In the Therion data I have a CS command and a fixed station, but maybe this is not exported to the 3D file for consuming by Survex. Most of the 3D file looks binary and I can't find out whether it contains this info or not. Vladimir On Thu, Mar 24, 2016 at 3:28 PM, Wookey <wookey@wookware.org> wrote:
+++ Владимир Георгиев [2016-03-24 13:41 +0200]:
Hi
I was experimenting with the .3d model exported from Therion to Survex. The Survex viewer (Aven) has an option to display the terrain too. When I go to View > Terrain I get an error "No coordinate system specified in survey data".
A terrain model has co-ordinates in real-world space, so you cave needs to also be located in real-world space (not just arbitraty 0,0,0)
In the Therion data there is a coordinate system specified, fixed station as well as terrain data and it is displayed in Lox. Has anyone seen this error or had success in showing the terrain in Survex?
You need to add a *CS command to your data (co-ordinate system) to say what system is in use, and add a fixed-point (e.g. for the entrance) to say where in that space the cave is.
http://survex.com/docs/manual/datafile.htm (look for *CS)
Wookey -- Principal hats: Linaro, Debian, Wookware, ARM http://wookware.org/
On Thu, Mar 24, 2016 at 03:36:04PM +0200, Владимир Георгиев wrote:
Hmm, you seem to be talking about the original Survex data file. I see the format is similar to the .th files, but I meant producing a 3D file exported from Therion.
In the Therion data I have a CS command and a fixed station, but maybe this is not exported to the 3D file for consuming by Survex.
I suspect therion hasn't yet been updated to include coordinate system information when it exports a .3d file. It should be fairly easy to update - just call img_open_write_cs() instead of img_open_write() and pass in the PROJ4 projection string for the output coordinate system as an extra parameter.
Most of the 3D file looks binary and I can't find out whether it contains this info or not.
You can see if you use the "dump3d" tool - it'll include a "CS" line in the header section if the coordinate system is specified, e.g.: CS +proj=utm +ellps=WGS84 +datum=WGS84 +units=m +zone=33 +no_defs Or look for a string starting "+proj" near the start of the file itself. But if aven says there's no coordinate system specified, it's just checked that for you. Cheers, Olly
Thanks for the info. Seems that the data is not exported to the .3d format indeed. If I have the time I will try to find the place in the Therion sources where that export happens. On Thu, Mar 24, 2016 at 3:50 PM, Olly Betts <olly@survex.com> wrote:
It should be fairly easy to update - just call img_open_write_cs() instead of img_open_write() and pass in the PROJ4 projection string for the output coordinate system as an extra parameter.
I didn't understand that part. What would be easy to update? Those two functions are part of the Survex source (img.c) from what I see. Vlad
+++ Владимир Георгиев [2016-03-24 16:30 +0200]:
Thanks for the info. Seems that the data is not exported to the .3d format indeed. If I have the time I will try to find the place in the Therion sources where that export happens.
Please post the patch if you do that, and I can include it in the Debian build until there is a new upstream release. Wookey -- Principal hats: Linaro, Debian, Wookware, ARM http://wookware.org/
On Thu, Mar 24, 2016 at 04:30:54PM +0200, Владимир Георгиев wrote:
On Thu, Mar 24, 2016 at 3:50 PM, Olly Betts <olly@survex.com> wrote:
It should be fairly easy to update - just call img_open_write_cs() instead of img_open_write() and pass in the PROJ4 projection string for the output coordinate system as an extra parameter.
I didn't understand that part. What would be easy to update?
Therion's code should be fairly easy to update.
Those two functions are part of the Survex source (img.c) from what I see.
Yes. The second (relatively new) function needs to be used if you want to specify the coordinate system, but therion probably uses the first one (which has existed for a very long time). So it's a matter of changing which function is called by therion, and passing in the PROJ4 string describing the coordinate system to it. Therion also uses PROJ4 so the appropriate string should be available. Cheers, Olly
+++ Владимир Георгиев [2016-03-24 15:36 +0200]:
Hmm, you seem to be talking about the original Survex data file. I see the format is similar to the .th files, but I meant producing a 3D file exported from Therion.
Sorry - yes. I failed to read your question properly. And Ol has now answered. Wookey -- Principal hats: Linaro, Debian, Wookware, ARM http://wookware.org/
participants (3)
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Olly Betts -
Wookey -
Владимир Георгиев