[Therion] Using 3d Scan Data To Create A Map

[Pavel Herich]

This software should do it:
https://geoslam.com/hub/
P.


Dňa 2019-06-20 09:26 Martin Sluka via Therion napísal(a):
> I’m curios if there is a software able to create  vector map outline
> from cloud data automatically.
> 
> Martin
> 
> Odesláno z iPhonu
> 
> 19. 6. 2019 v 23:13, kevin dixon <geospatial3d at gmail.com>:
> 
>> Nick,
>> 
>> I have both DistoX2 and LiDAR data for parts of the same cave.
>> 
>> All the LiDAR scans were registered to create a single model as normal
>> for LiDAR.
>> The individual scans were then decimated in the Point Cloud Software
>> using a suitable distance to nearest neighbour. I found Survex gets a
>> bit overwhelmed with millions of LiDAR data so you may have to
>> experiment with a suitable distance between adjacent LiDAR data. Each
>> decimated individual scan was then output to LibreOffice Calc and new
>> ranges, bearings and inclinations calculated to create single station
>> Survex files with lots of splays, now all orientated the same way.
>> Dummy traverse observations were created within Survex to link all the
>> LiDAR scan stations based upon the Point Cloud registration
>> coordinates and elevations of the scan stations.
>> I then manually matched the Survex output of the above LiDAR data to
>> some known DistoX2 observations or in your case, perhaps known show
>> cave outline. You can do this within Survex by having your non-LiDAR
>> data as another survey then using a Calibrate Compass figure (may
>> require up to +/-180degrees) within the LiDAR Survex data to change
>> the orientation so as to match the known and also setting one of the
>> LiDAR stations within the Dummy traverse observations to coordinates
>> and elevation that give a good fit with the known data. Several
>> iterations are needed with these.
>> 
>> Hope that is self explanatory.
>> Has worked for me - I have a DistoX2 Survex model with very detailed
>> LiDAR data in two large chambers - the resulting LOG file looks a bit
>> weird eg.
>>     1 8659-node.
>>     1 19071-node.
>>     1 21844-node.
>>     1 22774-node.
>>     1 23053-node.
>>     1 24470-node.
>>     1 25278-node.
>> 
>> As a side note, part of my project includes a Show Cave and I have not
>> had a problem with insitu metalwork there or on scaffolded sections of
>> the cave. I have always kept the DistoX2 well away from metalwork and
>> when the passage is narrow with metalwork, I have used an intermediate
>> station with DistoX2 observations to it only, never from it.
>> I have considered the use of turned angles to get through a serious
>> metaliferous section - the Leica DST360 could do this for you or a
>> small theodolite - use magnetic obs at each end to orientate it all.
>> 
>> Kevin Dixon
>> 
>>> On Wed, Jun 19, 2019 at 9:02 PM Nick Bairstow <Nick at pff.uk.com> 
>>> wrote:
>>> 
>>> Hi, Something a bit different for the clever people out there.
>>> 
>>> 
>>> 
>>> I have been playing with some 3d scan data and have attempted to use 
>>> it to create a Therion map.
>>> 
>>> Firstly we put created an outline of the cave passage using point 
>>> cloud software and exported as dxf.
>>> 
>>> I turned the dxf into a background sketch and drew around it and 
>>> could output a nice pdf of our cave. Also did a manual scaling. So 
>>> far so good.
>>> 
>>> 
>>> 
>>> I added a dummy station and gave it entrance coordinates, then 
>>> exported as a KML model. When I open the output file Google Earth 
>>> fly’s to the correct spot and shows a pin with the cave name but no 
>>> cave.
>>> 
>>> My question is , does this fail because we have no survey data, 
>>> centreline etc and it is impossible to do this or am I missing 
>>> something.
>>> 
>>> 
>>> 
>>> As an alternative I can export to an esri shp file and run that 
>>> though Qgis and get what I want but as I am going to attempt to 
>>> combine the 3 scan data with a several normal disto surveys I would 
>>> like to see Therion Kml output work if possible to save lots of 
>>> messing around. (GIS makes my head hurt)
>>> 
>>> 
>>> 
>>> On a side note using the point cloud software I can slice though the 
>>> scan data on different planes and pick up lots of detail, rocks and 
>>> boulders etc. Using the dxf/background image method I should be able 
>>> to get a very accurate representation of the passage. I can hear you 
>>> all saying what the hell is he doing that for when he could just 
>>> survey the cave in the normal way! Well the cave is a show cave and 
>>> absolutely rammed with metal walkways and cables. Disto tests showed 
>>> wild inaccuracy’s so it was looking like the only viable option was 
>>> going to be to use a Total Station device which we don’t have.  We 
>>> then had a very kind offer to scan the cave, this has proved to be 
>>> very interesting but drawing a normal map is a bit of a challenge 
>>> although it seems not impossible.
>>> 
>>> 
>>> 
>>> Any help would be appreciated.
>>> 
>>> 
>>> 
>>> Nick
>>> 
>>> 
>>> 
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