Working with drone contour/topo data

I’ve never gotten off the ground, so to speak, with some drone-collected contour data for my property. Here’s a list of issues:

  1. data are hosted by a site that isn’t Sketchup-savvy; the best their tech support has been able to do is to link me to a dxf conversion of whatever the native files are. I think they cater to mining and large earthwork-related concerns, which probably have proprietary software that works without all the fuss. I think my data are supported by subscription held by the man who did my drone-survey work, but the data-processing end of this isn’t his thing, so I can’t get much help from him.
  2. That dxf (6" contour intervals) is about 354Mb. I can import and open it, but even if my first action is to pare it down to just my property (vs several neighboring ones), something chokes and the file crashes eventually. All contours are already selected when it opens, so I’ve not been able to try the eraser-tool (etc) to try to make it less ungainly. I can navigate around on it with patience, change to parallel projection, etc., with each moving taking five or ten seconds or thereabouts.
  3. The data were expected to be a compromise, because of lots of large trees that cover the actual topography, and this has proven out in what I’ve seen in my attempts to look over the contours. My plan was to just visually/manually approximate the contours where such cloaking exists, simply by freehanding any given contour line until it meets up with the next ‘loose end’ after the interfering tree (I don’t expect this to be perfect, by any means).

Is there any go-to resource for this kind of project? I’m hoping to produce a set of somewhat-accurate contours sufficient to provide to an architect to permit planning for some retaining-walls and cut/fill work. The 6" contours were…optimistic. I’m open to hiring this out, if that’s even an option…though it’s probably only I who could ‘paint in’ the many contours that are obscured by trees etc.

Thanks - Dave

This ideally needs to be reprocessed in the photogrammety software to elimate the vegetation if possible. Most applications have a cloth type filter to remove buildings/trees etc. The the contours can be recreated reflecting just the surface data

here’s an example - it’s needs fine tuning but this is a few seconds work to remove the trees (red is the ground)

Regardless, the dxf will need simplifying for SU before you edit it it as it’ll be 1000’s of tiny segments or use a CAD application if you’re familar with that option?

This might help as a start?

Thanks, samnorth. To clarify, the photogrammetry software would be something the host site ( would own and presumably use to process my data? Or is it something I’d need to get my hands on?

In your example, there is of course still a lot of vegetation, so do you mean that it’s not yet been processed as you described? Or there’s some degree of control in that process to selectively clean it up?

As to the simplifying you mentioned - via curvizard? I’ve run across that before but can’t recall what I’d needed it for.

No problem. The processing has to be done in the photogrammetry application, in this case Propelleraero, which you wont have access to. I’m not familiar with it, but you could ask them to try and reduce the amount of vegetation if it’s causing a problem -

My example was just to show the ground (red) being selected with a filter. From this i could create a mesh and ultimately contours without too much interferrance from the vegetation. It’s different software but the same principle.

The dxf contours will be made up of a huge number of tiny segments, which SU doesn’t like. You just need to simplfy the geometry first to make it more manageable.

There’s a lot of threads on this already including sketchucation for reference but plugins to try are

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