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Orthophotos with Inspire 1

how did you calculate and maintain the side lap?
it was first lines as made on camera mode to try to keep the 50% overlap, after that i changed to map mode and try to keep the same distance
also, what accuracy does pix claim to have?
what you mean with "accuracy", the ground resolution?
if is that, for first flight (70 mts altittude) was 3.26 cm per pixel
for second flight (120mts) was 5.46cm per pixel

if it isnt, where i can see the accuracy?
 

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yeh thats what I reffered to.
I strongly doubt that you can achieve that accuracy in pix with the I1.
I may be wrong, I'm not an expert in photogrammetry, but I have spent the last 5 years selling drones to experts in photogrammetry and working in a company that specialises in it. So I have picked up a few things.

I do know people who have achieved very high accuracy with older 12mp cameras, but they really know what they are doing, and have done a lot more than simply fly lines with a time lapse set...

I dont mean to offend.
 
dont worry, my flights was just for testing purpose to see if i can use it or i will need a new drone if i get the contract, anyway, having real orthophotos made by me helps me when be negociating, intead of going with some downloaded orthos from who knows where

also the experience helps a lot at the time of calculationg the charge ($$$)

so help me, is there some way to confirm or verify the "accuracy"

what im thinking is comparing some clearly point from my ortho vs the gps position taken by (i hope i get) some pro GPS to see how much is the gap
 
its definately good to test pix and become familiar with the process before taking money for it, but be careful. Many people sell what pix makes as if it were something that it defeinately isnt.

On the other hand, what GPS did you use to take the coords in the corners? can you get it again?
 
its definately good to test pix and become familiar with the process before taking money for it, but be careful. Many people sell what pix makes as if it were something that it defeinately isnt.

On the other hand, what GPS did you use to take the coords in the corners? can you get it again?
i will ask, because it's my cousin's hangar, and he sent me the coords, but he told me he paid for profesional gps to verify coords when he bought it
 
well. how can you be sure that you have exactly the same point marked in pix? is there a visble landmark that is not huge? Ie something the size of a football that has been measured?
 
well. how can you be sure that you have exactly the same point marked in pix? is there a visble landmark that is not huge? Ie something the size of a football that has been measured?
not at the moment, but i was thinking, measuring some clearly edges of the "H" for example and comparing

esquinas.jpg
 
yeh , if you can measure those corners and then compare that would work, try to measure in other areas too. like the painted lines on the road......

I have spent hours and hours too many times to remember talking over the subject of UAVs in ortho generation. and whereas I havent studied photogrammetry, I do now know a few things.
 
its a good idea, maybe not every pict have same accuracy, thanks, when i have some more info i will let you know
 
Just a few personal thoughts on all this. Accuracy is only relative to what the client requires. I don't use any camera generated geotags as the accuracy is down to the multirotor gps accuracy. As far as I remember from DJI specs it's about 2.5m. However for some uses it may suffice.

Getting known GPS points from hi res commercially available hi res orthos like in N. Ireland supplied by our Land and Property Services which gives sub 0.5m accuracy. If these known points are visible in your own taken mosaics then you can have sub 0.5m accuracy (Using the Georeferencer Plugin in QGIS). In other words naturally available Ground Control Points without having to hire in a high accuracy GPS unit.

For surveyor accuracy of cm accuracy then you would professionally referenced GCPs.

I also have used still frames grabbed from 4K video giving around 8mega pixel images. Not great but for many purposes it is sufficient. It means I can choose my linear overlap.

Greater accuracy can also be achieved by flying slower and lower. Large areas on the other hand can be done at 400ft but with less pixel/cm accuracy.

Just trying to expand the scope of discussion a bit at the risk of stating the obvious on some points :)
 
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im now downloading qgis to give it a try

i will let you know what was my accuracy with the current project
 
Irish, did QGIS also do point clouds and calculate index or is just for orthophotos?
 
Irish, did QGIS also do point clouds and calculate index or is just for orthophotos?
It doesn't create point clouds, you would need Agisoft Pnotoscan Pro, which is the one I have or pix4d. You can import your point cloud as a layer in a stack of different xyz formats like .las for example. Georefed orthos too can go in on a layer and superimpose it over the likes of Google Earth, Bing imagery etc. You can do various things like set its transparency, draw poly lines on a seperate layer, plus a ton of plugins that a haven't clue how to use.

Here is a screen shot of QGIS with 2 georefrenced orthomossaics taken using DJI Ground Ststion and a Phantom 2 with 5.4mm lens in the GoPro. It is overlaid on Bing Imagery. You can see the red dots of the points I used for georeferencing.

b3115102f4c7a4ffadcd4858b67f79c3.jpg
 
It doesn't create point clouds, you would need Agisoft Pnotoscan Pro, which is the one I have or pix4d. You can import your point cloud as a layer in a stack of different xyz formats like .las for example. Georefed orthos too can go in on a layer and superimpose it over the likes of Google Earth, Bing imagery etc. You can do various things like set its transparency, draw poly lines on a seperate layer, plus a ton of plugins that a haven't clue how to use.

Here is a screen shot of QGIS with 2 georefrenced orthomossaics taken using DJI Ground Ststion and a Phantom 2 with 5.4mm lens in the GoPro. It is overlaid on Bing Imagery. You can see the red dots of the points I used for georeferencing.

b3115102f4c7a4ffadcd4858b67f79c3.jpg
looks really nice, but........ its kind of hard to use if you are not in the business
i was trying, looking tutorials on youtube and everything and couldnt import my original photos for making the mosaic, I quit :p

pix4d seems or, to basic (that i dont think it is) or very easy to use
 
Thanks for sharing Irishsights. I've downloaded QGIS and will take a look tomorrow (my eyes are bleeding at the moment from working on my Ops manual!) I've seen you before - on Multi-rotor UK forum. Small world eh! I'll let you know how I get on!
 
dont worry, my flights was just for testing purpose to see if i can use it or i will need a new drone if i get the contract, anyway, having real orthophotos made by me helps me when be negociating, intead of going with some downloaded orthos from who knows where

also the experience helps a lot at the time of calculationg the charge ($$$)

so help me, is there some way to confirm or verify the "accuracy"

what im thinking is comparing some clearly point from my ortho vs the gps position taken by (i hope i get) some pro GPS to see how much is the gap

Yes, you can export as a KLM file and import it to Google Earth. This will give you a good idea of the accuracy of your Geotags. My partner and I have had great success with the Inspire using Pix4D and MapsMadeEasy.
 

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