We (www.gmxconsulting.co.uk) are developing a large-scale agriculture project in Nigeria (5,000ha) and started to use drones to survey and map topography.
The intention was then to use the Digital Elevation Model for irrigation planning and design. However, when we post processed the images we got very large x y z errors - please see the photos below.
1. Could anyone tell us where we have done wrong? Can we correct NOW (after the aerial survey)?
2. Also we look to outsource the drone surveying and post processing for our projects in Africa - Anyone interested please let us know.
Here are some more details:
Platform: E384
AGL: 120 - 180m
Overlap: Front 60% Side 60%
GCPs: No
Flight time: <60 mins
Cameras: Canon S110 RGB and NGB
Number of photos: 300-400
Photo taken out before processing: None
Software: Photoscan
Many thanks in advance!
Replies
Thank you Eladio for your advice. We thought lacking GCPs could be the issue. As this was a remote area we didn't have a recognised datum so could never quite confirm the exact geographical position reference point. We will next time use DGPS first to work out "where we are in the world" then put down the GCPs as recommended. We will also try to delete the photos around the edges. All the images looked quite sharp though.
We were reluctant to increase the overlapping because of flight time constraints. We did see that people use 80% for both. That would increase the processing time significantly though.
When you process the image with Photoscan, does quality option 'medium' or 'high' affect precision? Again we were limited by computing power - just a Quadcore i7 16GB Ram laptop - so couldn't go for the 'high' option. Any suggestion on building a cost-effective high-power processing hardware would be appreciated. Or can we lease computing power?
Hi Quan,
I really love business opportunities and
like your
Drone topographical survey for agriculture in Africa
challenges
since as Climate Change Consultant with UNFCCC I join projects by UN agencies,
World Bank, UN Foundation and other public agencies.
I need to study a number of your images, geolocated as Google Earth/ Maps overlay first.
I need geolocations for your regions to study with available Google Map, Earth, OpenMap mapping systems and more.
Could you provide me with technical specification of your drones to let me check if they are fit to accomplish your task.
Let me know your deadlines now and size of your imaginery database in MB, GB
and if you can upload images over the Internet if necessary.
I am sure, we can get a lot of invaluable materials from IRENA in support of your irrigation planning and design.
pls email me
darius
CChC
manta103g@gmail.com
Thank you Darius for your comments. I will try to send a link to dropbox folder containing the raw images and processed data from Photoscan.
You will see a google kmz file with location on Google Earth.
For drone we used E384 https://www.event38.com/Articles.asp?ID=289
@Quan,
files received, 2 files parsing problems.
email me back
manta103g@gmail.com
Hi Quan, I am looking to buy E384 and would love to learn your experience with them so far. I am also available at ruchit@harvesting.co
Hi RG sure you can email me at quan.le@gmx.com
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