Does anyone have good workflow to import a DSM / DEM into TBC? This seems like it should be straightforward, but once I am able to get it to import it doesn’t seem to contain any of the elevation data. In C3D I can import into a surface and utilize it there, but I want it over in TBC to run reports of check shots. Only other option is to explode into some density of a grid file that just turns into a mess and hard to work with at a resolution that is still is representative of the site.
Send me a file to look at Elijah and I will see what is possible
Alan
Hey Alan, attached is a file from a lidar flight. I use a processing service that produces great contours, but their only surface output (representative of said produced contours) are these DSM files. I have a bunch of conventional survey shots I would like to run and report the deviations for QC. Also attached is a dxf of the final contours produced.
dem.tif (46.7 MB)
contours_balanced.dxf (6.8 MB) contours_roughest.dxf (20.0 MB) contours_smoothest.dxf (3.0 MB)
@alan.sharp Another observation is that if you run a project through Photogrammetry in TBC and elect the dsm deliverable, it will insert the dsm into the project and is visible. How to use any of the elevation data from it, I have no idea. ha
Any word on this? Can i get an update?
I have a developer taking a look at this to see what it will take - i will respond when I have an answer
Alan
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Hey Elijah,
My preferred routine is to import in C3D with a data clip to the area of interest. Then I edit surface style to display points/border only. Last (as you mentioned) I explode and save the dwg. Import into a fresh TBC template, build a surface from the points, apply border, and export as a .xml and .ttm. Using points and boundary only is the smaller file size definition I can find. If I take back into c3d, I use the xml and don’t have to worry about using the over sized dem(I am utilizing giant LiDAR files with a small internal area of interest). If I take into a tbc working vce, I use the ttm as the file size is smaller. I like to try to avoid more than 100k points, files get big.
Alan,
during your discussions with devs, if they were to add functionality to import DEMs, it would be critical to be able to set the import coordinate system/datum/units. Then the ability for it to be translated to the datum/CS of the vce. For example, the data sets I use are provided by the usgs and are defined in Nad83/UTM/Meters. I then convert to my local state plane/international feet. Otherwise it’s primarily just a grid point file. Would be a great tool to add to TBC or handy addition to the Rockpile toolbox.
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Being able to import a DSM and manipulate it would be useful. I use propeller and cannot use the DSM outputs directly as they are too large. Ideally for me it would be handy to slim down a DSM for my drone as it has a limit of like 20mb if I recall. Then I could have an up to date surface for terrain following with the drone.
Any update on this Alan?
What benefit does the DSM output have from Propeller over the LAS files that you can also get from Propeller - I use the LAS files all the time on projects that we are working and I run our Point Cloud Processor on them to prep them for Modeling - that reduces their size intelligently so I have a small point cloud with data where I need it that I use for my surfaces.
I hear you all on the use of DSMs if that is all you get - but why get those when you have the option for a LAS file and Ortho Photo as well ?
Please explain the benefit of a DSM to me when you have a choice?
Alan
Alan,
For my use case the DSM would be intended for a drone. Currently the publicly available DSM files are of low resolution and old age. They don’t always match the existing terrain very well, more so in mining areas. Drones use this DSM to follow the terrain. Trimble stratus (aka Propeller) provides a DSM but the files are much larger than the drones limit of 20mb. It would be nice to be able to edit the DSM in TBC to thin the file and have an up-to-date model for future flights.
My experience is limited here but it seems to me that I created a “DSM” from contours. That survey was almost a year ago so details are a little hazy. I created the contour map from an earlier flight and loaded for the “DSM”. This could have also been a function of Wingtra’s software…
It seems - if one can get the data for the terrain follow from contours or surface, Alan’s logic would be on point
My use case for this was that I wanted to deliver a surface file to the client that was a 1:1 of the contours created from a Rock Robotics Deliverable. At the time they would only allow you to download the surface as a DSM, so you if were directly providing the contours you had to also provide them with a DSM. It seemed like it was hit or miss if a client knew what to do with that unless they were into GIS.
I agree with Alan in that using the Point Cloud Processor is the better way to deal with this. You can clean the point cloud and have a 1:1 surface file all in TBC. I just thought it was odd that TBC Photogrammetry Module would bring in a DSM, but you could not bring in an external DSM.
That being said, some online elevation resources only allow the download of DSM/DEM so it would be useful in some cases to be able to read in that type of file. ie I think our state lidar data is only available in DEM.tif
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