im refining my workflow for some commercial drone work that includes WEBODM and QGIS.
im outputting Geotiff and orthotiff from WEBODM and using these to create an ortho with tight contour lines to help identify materials in stockpile on construction sites.
it struck me that this was far easier on the eye than drawing polygons in WEBODM (either ortho or DEM) to identify the base of stockpiles- the contours really draw the eye and make it easy.
I know you can output .geojson files from QGIS (which could be the outline of the stockpiles). is there anyway of bringing these into WEBODM as an outline for WEBODM to calculate volumes?
I build oil field locations and I use DTMs from WebODM to calculate quantities of material to move. I don’t see why you couldn’t use the same process for stockpiles.
I create regular points at 1’ intervals and clip them with a polygon. Then it’s as simple as adding everything that’s above my average elevation. That gives me cubic feet and I divide by 27 to get yardages
I see that your wanting WebODM to calculate your volumes based on exported json files from Qgis.
As i said before i use qgis to calculate volumes but its a tad more involved and i responded with assumptions that you have other things in place. So here is my process and you will need the point sampling plugin for Qgis.
export the DTM from WebODM
import the raster into Qgis
Draw the polygon around what you wish to measure
create regular points at 1’ intervals (is use 1’ for ease of calculation) from the vector/research menu
vector/geoprocessing tools/clip the created temporary layer by the overlay polygon
Use the point sampling tool referencing the clipped layer and sampling the dtm
export the created layer from the point sampling tool to .csv where any spreadsheet can but used for calculation(I have no doubt that this can be automated in Qgis but for now this is how I’ve done it)
multiply elevations by 3.28084
subtract your base elevation from the result
add all positive integers to obtain cubic feet
It’s not what you were looking for but maybe it helps
since it turned out my first idea was a bust, i went back to investigating.
I have been playing with a QGIS plugin called “Volume Calculation Tool”. it does exactly what i want all within QGIS. its also very easy to present and label the stockpiles based on the attribute table output.
all use cases are slightly different - my biggest issue with WEBODM for calculating volumes was that my job sites are usually very congested with stockpiles merging into one another, and stockpiles of subsoils being sat on the same subsoil material making the edge difficult to define. This isnt limited to WEBODM as i have trialled some of expensive modelling software. The act of creating contours in QGIS from the DEM makes it really easy to home in on the base of the stockpile, and see where piles merge. This isn’t alway easy with either the orthophoto or the RGB DEM.
quick update. i had three jobs lined up - i had done the photo/video work and saved the modelling until last.
the system i mentioned in my previous post was revelatory. having the contours to work to was a million times better than trying to “eye” the base of stockpiles.
plus the output is labelled and there is an attribute table with the volumes that i can use on my drawing. just a simple matter of exporting a jpeg of the finished product, dropping it into AutoCAD and sheeting it up.
QGIS seemed almost impenetrable at first - the learning curve seemed vertical just to complete the simplest of tasks. im glad i stuck at it, as it seems to be the solution to most of the process issues i have when working on my drone models.