GeoSlam data and level to ground

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cbresloff
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GeoSlam data and level to ground

Post by cbresloff »

Hi folks,

I have a bit of an ignorant question to ask about the Zeb Revo units. My company purchased a few of the Zeb Revo units before I came on board, so I've probably missed some info about what they can and cannot do; yet I am now an end user of one. I understand the units have an IMU but I am unclear on whether or not this implies whether the units 'know' where level to ground is, in the scan data (I suspect it depends on the particular IMU?) . I think of the generated point clouds from the Zeb units as giving location information in a relative sense and not absolute; yet the scans appear to bring the data in relatively 'level'. Is this something I can count on, that the data is oriented with some accuracy relative to level ground, or not?
Thanks.
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Re: GeoSlam data and level to ground

Post by tbwester »

when you start the revo (on a basically flat unmoving surface), it sets the level for your scan. We count on the scans being basically level, not sure exactly how good it is, but we find it to be good compared to our higher end tripod scanners.
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Re: GeoSlam data and level to ground

Post by stutosney »

It has been a while since I used it, but from memory it uses the initial start up as your level plane, and then the rest of the data is based around that. I think it was similar to the BLK, it uses the first scan as the plane and then relates that to the rest of the scans.
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Re: GeoSlam data and level to ground

Post by gsisman »

stutosney wrote: Tue Sep 24, 2019 9:58 pm It has been a while since I used it, but from memory it uses the initial start up as your level plane, and then the rest of the data is based around that. I think it was similar to the BLK, it uses the first scan as the plane and then relates that to the rest of the scans.
Does anyone know that when using these geoslam devices that you can walk close to and densely scan,say a wall target and then add that control into the processing scan cloud to more precisely tie to control coordinate system bot vertically and horizontally?
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Re: GeoSlam data and level to ground

Post by VXGrid »

gsisman wrote: Wed Sep 25, 2019 2:15 pm Does anyone know that when using these geoslam devices that you can walk close to and densely scan,say a wall target and then add that control into the processing scan cloud to more precisely tie to control coordinate system bot vertically and horizontally?
There is now a way to include control points into the SLAM algorithm with the new version of Hub.

If you just want to georeference the local point cloud you can do that with that approach as well, or use GeoSLAM Draw (Transformation calculator - 7 parameter transformation) to gereference the cloud using spheres/checkerboard targets.
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Re: GeoSlam data and level to ground

Post by Mokeefe »

cbresloff wrote: Mon Sep 23, 2019 6:26 pm Hi folks,

I have a bit of an ignorant question to ask about the Zeb Revo units. My company purchased a few of the Zeb Revo units before I came on board, so I've probably missed some info about what they can and cannot do; yet I am now an end user of one. I understand the units have an IMU but I am unclear on whether or not this implies whether the units 'know' where level to ground is, in the scan data (I suspect it depends on the particular IMU?) . I think of the generated point clouds from the Zeb units as giving location information in a relative sense and not absolute; yet the scans appear to bring the data in relatively 'level'. Is this something I can count on, that the data is oriented with some accuracy relative to level ground, or not?
Thanks.
There should be a process to tie in survey points and levels. If that isn't accurate enough, you might want to check on a higher end mobile scanner like the Heron. It lets you tie in points and levels, and even use terrestrial scans as controls.
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Re: GeoSlam data and level to ground

Post by stutosney »

gsisman wrote: Wed Sep 25, 2019 2:15 pm
stutosney wrote: Tue Sep 24, 2019 9:58 pm It has been a while since I used it, but from memory it uses the initial start up as your level plane, and then the rest of the data is based around that. I think it was similar to the BLK, it uses the first scan as the plane and then relates that to the rest of the scans.
Does anyone know that when using these geoslam devices that you can walk close to and densely scan,say a wall target and then add that control into the processing scan cloud to more precisely tie to control coordinate system bot vertically and horizontally?
As far as I know, you can acquire targets with the Zeb Revo devices. I didn't do it myself but I remember speaking with GeoSlam and they said it can be part of the normal workflow, this was about 3 years ago.
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