Landslip 3D model + DTM

Early last Friday morning before sunrise a small slump occurred on a steep cleared slope about 20km from here, which I noticed while riding past on my bicycle. I obtained images on Tuesday, the images used here were mostly taken from 50-60m AGL, with about 100 taken from 25-30m, concentrated around the slump.
A few decades ago I’d noticed the signs of a previous slump (slight bulge to the right of this slump, with black dots on DTM), and when the owner had some earthmoving done to create a flat area just above it 3 or 4 years ago, I figured it was only a matter of time before another slump occurred.
Lots of rain the past 2 1/2 years, following the worst recorded drought lasting 2 years immediately before that, and particularly 140mm in September, got things moving. Apparently there was a slight amount of movement on the Thursday afternoon, but most of the movement was early on Friday 30th September.

531 images 19:24:08

|Options:|auto-boundary: true, dem-resolution: 2, dsm: true, dtm: true, mesh-octree-depth: 12, mesh-size: 300000, orthophoto-resolution: 1, pc-quality: high, pc-rectify: true, resize-to: -1, use-3dmesh: true|
|Average GSD:|1.29 cm|
|Area:|57,384.25 m²|
|Reconstructed Points:|113,489,287|

Some earth moved downslope on the right hand side of the DTM, mostly eroded and accumulated at the bottom, rather than slumping.


I love stuff like this. Have you tried CloudCompare for looking at changes over time?

1 Like

I haven’t, but I might try it if there is any movement over coming weeks or months.
Unfortunately I don’t have any pre-slump imagery.

Volume measurement in WebODM for the hollow suggest it is nearly 150 cubic metres in size.

1 Like

The lower AGL set of images I took, which failed at ultra feature quality, has succeeded at high feature quality, results here-

410 images 22:25:21

|Options:|auto-boundary: true, dem-resolution: 1, dsm: true, dtm: true, gps-accuracy: 6, mesh-octree-depth: 13, mesh-size: 600000, orthophoto-resolution: 0.5, pc-quality: high, resize-to: -1, use-3dmesh: true|
|Average GSD:|0.48 cm|
|Area:|21,824.39 m²|
|Reconstructed Points:|98,132,345|

Every blade of grass resolved :slight_smile:


Looking good! I did get good results from using ultra, though I haven’t tried all of your settings.

1 Like