How large an Area can DD process in a single map?

#1

I have a client asking me to give him an ortho mosaic of his 2300 acre ranch.

He also wants a 3D model of the property with a special interest in vegetation conditions.

Can even DD do this?

I understand that it will necessary to break up the missions in to about 6 pieces as a minimum.

My big question is can the missions be combined to give a single output?

I have also considered overlaying the several orthos on to google earth to try for a single 3D map. This is not ideal, a cloud based solution would be best.

Thank you

#2

I would breakup the flights as you mentioned the open all the images together in QGIS. It’s very straightforward. You can then Save As and export all the tiles to a single image. I can create the stitched 3D model if you don’t have the software to do it.

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#3

Is there a video you could link to this process?

This is the largest job I have been asked to do. Previously 100 acre jobs have been the max requested of me.

If I am following you correctly, Qgis can combine multiple orthos together. How large of a file would the 5000 image capture create?

More importantly how would you share a project of this size with a client? Would they need a serious computer to see the render?

This client is not tech savvy and really just wants to be able to zoom in on any point of the ranch with high detail and references the points to the terrain around them.

This is something that is easy on a smaller property, but possibly out of my experience at this scale.

#4

Let me see what I can find or I will make one. It is a monster job, but should be manageable. It will take patience because we don’t have a server farm like DD… :smile: The total image size will depend on what resolution you export at. I would try at 8in/px first just to run through it. You may be able to get down to 4in/px, but I bet that will be a chore.

Honestly I think you were on the right track with Google Earth. You could export everything as WGS84 and open them all in Google Earth by creating Super-Overlays. Once they are all loaded then just Google Drive the tiles it creates as a KML. The will need the whole folder you create.

#5
#6

Here’s a video to get the Master Orthomosaic through QGIS and a link to download QGIS below it. My Mic doesn’t work too well, but it’s pretty easy so hopefully just watching the steps works. QGIS should default to the WGS84 projection so make sure to download your orthos the same. Last, but not least… Save the QGIS project so that you can return to it later and don’t have to start all over. Once you get this down then we can talk about other things you can overlay in here. Thanks!

https://1drv.ms/v/s!AqjnqLnFlIbogu1zg20Rct85ySf3pg

https://qgis.org/en/site/forusers/download.html

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#7

When you export the combine orthos in qgis to PDF as I believe you said, are you loosing the geo tag information?

Thank you for making the video! I struggled to hear the audio, but I think I got most of it.

#8

Correct, “flattening” to a PDF removes the Geotags. I think that is where Google Earth would be the easiest choice for georeferenced data. PDFs are great to just look at, but if you want to use that info for future planning then QGIS and Google Earth are the way to share. If you form a long-term relationship with any of your clients then that is where it would be beneficial to train them on a free program like QGIS. Especially in our industry we are seeing more and more younger people with GIS experience. Here is the same info from Google Earth. The entire dataset is only 25mb. Just ZIP it and send.

https://1drv.ms/f/s!AqjnqLnFlIbogu136udypqJV96UjwQ

#9

I’m getting with a peer that is a City GIS Manager to see if he knows a way to merge multiple Geotiffs and export to one while retaining the georeferencing.

#10

I use arcgis to do this, no problems. QGis also works.

I also typically restrict each mission to about 500 acres with decent overlaps. Typically I will fly a high altitude (450 ft if possible) low resolution flight, load it into arcgis, then construct shapefiles for the project. They can be imported into DD to set the smaller missions.

Works well with P4 and M2P, but you will need to have lots of batteries. There is also an issue in DD with battery changes, as it will sometimes return to the wrong waypoint, skipping a flight line. Watch the flight and force a return just after turning a corner seems to work instead of waiting for a low battery return.

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