Questions & Answers - Drones for Community Mapping
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- Are your drone images also being uploaded to Wikimedia Commons, for
use on Wikipedia? - Andy Mabbett, @pigsonthewing
- Not currently, but many are posted on OpenAerialMap under open
- this the imagery in the slide:
- Arenda imagery:
- How do you produce DTM, are you sing Pix4D and what are the quick
- Yep! I used Pix4D to generate DTM. You can check this diary
entry I did for the Lupang Arenda example:
- Is there open source software for processing drone images? Pix4d is
not open source.
- Yes, you can OpenDroneMap which is opensource. -maning <3
- do you have any exeperionce
- The OSM community in the Philippines have a bit of
experience using OpenDroneMap and we are now experimenting
with various settings to try and generate optimal orthophoto
- Do you have the base map of Batad uploaded online somewhere?
- Yep, you can check here:
- This is awesome work! What were the reactions of the local
communities that you worked with? Were they generally cooperative?
Did they like the output when you shared it with them?
- For Batad, they do not like drones in the area because it was
noisy. But after the team explained it to the people, they were
okay with it. We explained as much as we can why we need to get
the data for research purposes and for their use as well.
- For Lupang Arenda, the drone mapping was actually a request of
the local government and they are now using the results of
mapping in OSM as part of their rendering of public services.
great to hear, thanks!
- more info about this community collab:
- thanks! great to see that there’s a lot of discussion about
- Are there privacy concerns (in case individual human beings are
visible on the images) - do you blur these images, or ask people for
- the 10cm resolution is not sharp enough to identify faces/people
- Yep I agree.
- Is there any manual work for removing buildings for DTM, or
everything done by software.
- To enhance DTM data, WhiteBoxTools’ RemoveOffTerrainObjects
module was recommended by a colleague.
- This is done automatically by software. Note that DTM is not
super accurate because it requires the software recognizing
trees and buildings and this is not very accurate. But the DSM
- So the DTM is calculated from parallax between images?
- Yes! Pix4D and OpenDroneMap uses computer vision
techniques to determine the “3D” shapes of objects and
uses that to calculate the DSM.
- Are there privacy concerns about objects visible on private ground
(in backyards, e.g.) not visible from the street level?
- In the works that I’ve done, we have proper coordination with
the government officials down to the local community leaders to
explain what we’re collecting. As much as possible we
communicate with the community what we’re doing and collecting.
So far, I haven’t had this before. - Leigh
- Do you have any equipments to adjust positioning like RTK or
- The drone itself has GPS capabilities to get the XYZ values. If
the project / area requires higher accuracy in horizontal /
vertical location, GPS Survey or adding GPS markers will help.
- We only rely on the GPS/GNSS technology included inside the
- Great work! How do you choose locations/projects? What will be your
- Usually from friends from the geospatial community ask us to map
out areas. I team up with other drone pilots, OpenStreetMap PH
community or involve Philippines Flying Labs to do the mapping.
Currently, I don’t have a next project due to the Corona Virus
pandemic. Hopefully by next year, I can map again.
- How much complex to geo-reference drones’ shots?
- All drone captured images have the location in its exif
metadata. All images can just be in a single directory and the
software can take care of the stitching and georeferencing.
This is the same for proprietary and open source tools.
- There are a few approaches to improve quality like taking
nadir/perpendicular + oblique. But in most cases, nadir images
with 60-80% overlap will generate good results. -maning
- Thanks for this sir!
- What’s the cost of such drones?
- Oh it’s such a huge range! It ranges from 1500 USD to 25,000
USD. hehe. - Leigh
- What is your message for girls all around the world who want to
learn to fly a drone?
- Go fly and enjoy it! Don’t be afraid of the technicalities of
- Go fly, and enjoy it (answer from Leigh) If people give you
reasons not to, don’t listen to them too hard (indiebio)
- Why not “listen to them if they provide a reasonable
explanation, and then make an informed decision taking into
account this information” Would this require a different
answer for women vs men?
- (I’m a girl and I would think yes - indiebio)
- There is good reason to encourage different groups of
people, but that’s a question for a diversity talk
- You are an inspiration for women all over our communities and seeing
you giving a talk about a highly technical topic gives us
- Thank You for the talk, and your time working on this project -
- I need to do more of this. Done quite a bit of the photogrametery
simalar to pix4D from the ground using a poleand a camera. GoPro
cameras work well as they have a gps. You can do it! happy to help
you as well!
- [There’s a problem with audio feedback - maybe encourage presenters
to use earphones?]