Posted by Matt Gunn on February 17, 2013 at 7:58pm
Im building my mapping rig with a fenwing penguin airframe. My apm is in the mail. Ive been doing aerial photography and video for a few years, but im ready to step it up with the mapping, and eventually 3d terrain mapping. My question is, do i want to use a camera with a built in gps that geotags the image, or skip that and use the apm to add the data to the images?Ive read that aeromapper recommends the casio h20g as the best camera for aerial mapping. Is this still the case? Any other camera recommendations?Thanks in advance.
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thanks for the info gents. i just had our 1st son a few days ago so ive not been able to check here. i do have a canon s95. id like to use it and the apm internal gps tag. ive had issues whit the s95 and its is lenses. they cause a blurry image with even the slightest vibes...
The only problem with using the camera's internal GPS is its accuracy. There's no way a cheap internal GPS buried within the camera is going to be as accurate as a dedicated uBlox GPS module mounted high with a clear view of the sky.
So I think it's a trade off between easy of setup/use (camera GPS) versus accuracy (APM+GPS). You only get the increased accuracy in the second case if you correctly correlate the time offsets between the camera and the APM's clocks though.
Which makes me think - cant you get a very accurate time sync from a GPS signal? If both the camera and the APM could do this it would help a lot.
Here are a few suggestions.. I would go with a camera like the Canon Powershot SX260HS which has built in GPS. You can run piggy-back firmware called CHDK and fine tune certain settings such as the GPS refresh rate (important for more accurate on-board geo-tags), shutter speed (1/1250th or better to reduce blur), and install a intervalometer script to shoot imagery every X seconds. The beautiful thing about a GPS enabled camera is the geo-tags are usually good for most applications, also the on-board camera clock is synced to GPS time making it much easier to reapply geo-tags to the images from an external source such as your flight controller log. So, you get the best of both worlds with this approach. We see a lot of great imagery that is difficult to geo-tag because the camera time and flight controller times are not synced or the operator doesn't know the offset.
There are also some great features built into mission planner that allow you to geo-tag your images if you don't have a GPS enabled camera. I believe there is a tutorial posted here on diydrones with this feature outlined.
Replies
maybe this article can reply your question about GCP
https://www.sigitriyanto.com/gcps-distribution/
I have been thinking of this also good to see a post started on it, I am trying to decide which would be better for this Multi or Fixed wing.
thanks for the info gents. i just had our 1st son a few days ago so ive not been able to check here. i do have a canon s95. id like to use it and the apm internal gps tag. ive had issues whit the s95 and its is lenses. they cause a blurry image with even the slightest vibes...
So I think it's a trade off between easy of setup/use (camera GPS) versus accuracy (APM+GPS). You only get the increased accuracy in the second case if you correctly correlate the time offsets between the camera and the APM's clocks though.
Which makes me think - cant you get a very accurate time sync from a GPS signal? If both the camera and the APM could do this it would help a lot.
Hi Matt-
Here are a few suggestions.. I would go with a camera like the Canon Powershot SX260HS which has built in GPS. You can run piggy-back firmware called CHDK and fine tune certain settings such as the GPS refresh rate (important for more accurate on-board geo-tags), shutter speed (1/1250th or better to reduce blur), and install a intervalometer script to shoot imagery every X seconds. The beautiful thing about a GPS enabled camera is the geo-tags are usually good for most applications, also the on-board camera clock is synced to GPS time making it much easier to reapply geo-tags to the images from an external source such as your flight controller log. So, you get the best of both worlds with this approach. We see a lot of great imagery that is difficult to geo-tag because the camera time and flight controller times are not synced or the operator doesn't know the offset.
There are also some great features built into mission planner that allow you to geo-tag your images if you don't have a GPS enabled camera. I believe there is a tutorial posted here on diydrones with this feature outlined.
Good luck!