I've been approached by a mining company about doing volumetric analysis of their coal stockpiles with my Phantom P3P. Is this currently possible with MME?
Sure. With the DEMs that are generated with all georeferenced workflows, it is possible to make such measurements various 3rd party softwares such as AutoCAD or QGIS/GRASS(free!). We hope to offer that capability natively on the site in the coming months. We'll look into posting a script that can be run in the meantime.
Vui lòng đăng nhập để lại bình luận.
I would be interested in that script if/when you post it!
Tudor, how accurate is the vertical elevation as obtained from the photo taken at the ground surface? Using no vertical elevation reference point can yield very un-accurate results for the DEM and such. On the other hand, survey grade Trimble GPS units can get vertical elevation to accurate within a couple inches or so. I'm guessing the ground reference photo (using elev from the aircraft's barometer) will be somewhere in between for accuracy of resulting DEM's after processing.
The vertical elevations are not as accurate as the X and Y locations are in a relative sense. We generally quote that the Z accuracy is around 3-4 GSD units. If you have 1 inch GSD, your accuracy is around 4 inches. That doesn't really hold true true though for vertical edges where anomalies can occur and other areas that generally don't rebuild quite as well. The DJI barometer actually has quite a bit of drift to it.
Everything here is relative to itself. For absolute measurements, we are only as good as the GPS and the barometer which are routinely off by up to 10 meters or more.
The place where these models shine is if you can get it sufficiently ground referenced with your Trimble unit by taking a few good samples. Then you can pretty accurately say what every other point in the survey area would be without measuring them all by hand.
