Interesting complaint from a mapping client...

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Hey doods!

For anybody who shoots video and/or photos for any kind of forensics purposes, you know that a cloudy day is the Holy Grail of lighting situations. Without the Sun, one avoids the hurdles often encountered with deep shadows. So when my partner and I get a chance to map on a cloudy day, we take it.

Recently, my partner and I mapped a small 17 acre plot about 2.5 hours from our home town (he often joins me because I think he likes getting out of the office for the day). My partner does all the Pix4D rendering. Upon delivery of the final map, the client complained that there were no shadows. HUH??? Apparently he uses the shadows to detect things like fence poles and barbed wire fencing, which become all but invisible from the air on a cloudy day. Interesting complaint. So now we have to add that variable to our check list. Does the property have a fence? Yes? Okay...no cloudy day shooting. This is kind of a bummer, because I LIKE shooting on cloudy days, especially in the Summer.

While I concede that it may be difficult to see barbed wire from 250' AGL, I certainly have no problem spotting regular fencing or fence posts.

1580314799673.png


Interesting.

Discuss.

D
 

BigAl07

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Wow.. just WOW!!

Yea overcast is PRIMO and what we absolutely LOVE!!

Honestly I never even considered someone wanting those nasty harsh shadows before. Go figure!!
 
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My initial scouting of a site that involves travel usually begins with a Google Earth aerial, followed by noting on a printout the various poles, wires, and other items I must be aware of for a safe flight. Naturally, I confirm these and add to the list during my eventual pre-flight site walk. So I find aerials containing shadows helpful in locating many of these vertical structures in advance for planning purposes. It's hard to overlook a long shadow.
 
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My initial scouting of a site that involves travel usually begins with a Google Earth aerial,

Yep. Always. My business partner sends a .kml, which I then use to build our flight missions.



...followed by noting on a printout the various poles, wires, and other items I must be aware of for a safe flight.

But when you're flying a minimum of 200' AGL (up to 400' AGL), telephone poles and power lines aren't a concern during flight. My only concern for these obstacles is during take off and landing. Ergo, we're only really concerned that the launch site location is away from these obstacles. And, of course, it's pretty easy to avoid these obstacles. To date - at least in my state - we haven't encountered anything 200' tall.



Naturally, I confirm these and add to the list during my eventual pre-flight site walk. So I find aerials containing shadows helpful in locating many of these vertical structures in advance for planning purposes. It's hard to overlook a long shadow.

We deal with a lot of elevation here, so that's usually our main concern. We like launching from the highest elevation for obvious reasons. The effect of elevation really hits home when you're on site. It looked so flat on the map!!! HA!

In my state, we use "terrain awareness" for just about every flight. That said...

Anyone who can't see telephone poles or power wires while on site should NOT be flying a drone for a living....<:^0

D
 
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Yep. Always. My business partner sends a .kml, which I then use to build our flight missions.





But when you're flying a minimum of 200' AGL (up to 400' AGL), telephone poles and power lines aren't a concern during flight. My only concern for these obstacles is during take off and landing. Ergo, we're only really concerned that the launch site location is away from these obstacles. And, of course, it's pretty easy to avoid these obstacles. To date - at least in my state - we haven't encountered anything 200' tall.





We deal with a lot of elevation here, so that's usually our main concern. We like launching from the highest elevation for obvious reasons. The effect of elevation really hits home when you're on site. It looked so flat on the map!!! HA!

In my state, we use "terrain awareness" for just about every flight. That said...

Anyone who can't see telephone poles or power wires while on site should NOT be flying a drone for a living....<:^0

D

Hi MapMaker,
Well you would think that telephone poles would be hard to miss... But last year I was filming a farming harvest with mainly low level flying. There was I think just one telephone pole in that field but while flying sideways parallel to the tractor I came very close to connecting with the pole - gave me quite a shock.

See
and skip ahead to 7:08 ...

Never say never!

All the best, Martin
 
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But when you're flying a minimum of 200' AGL (up to 400' AGL), telephone poles and power lines aren't a concern during flight. My only concern for these obstacles is during take off and landing. Ergo, we're only really concerned that the launch site location is away from these obstacles. And, of course, it's pretty easy to avoid these obstacles. To date - at least in my state - we haven't encountered anything 200' tall.

My flights vary a lot due to the fact that I film field work being done for our clients and also for our marketing people. This means I sometimes orbit 15 to 20 feet off the ground, or glide in from 100 ft a distance away to a close-in shot of the work being performed. So telephone poles and wires NORMALLY come into play in my work. I had a gig where town officials felt it would be pretty cool to have me to fly around their town and "visit" the annual murals that are painted on various establishment walls throughout the town. That was quite a challenge with many locations having a spider web of telephone and electric wires criss-crossing the town streets. But it was a fun gig.
 
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Hi MapMaker,
Well you would think that telephone poles would be hard to miss...

LOL. No, that was Harleydude who isn't afraid of poles. I've had a few near misses thinking from my vantage point that I was easily clearing a pole as I manually orbited. I now try to arrange for a second set of eyes to assist me whenever possible or the situation calls for it.
 
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Hi MapMaker,
Well you would think that telephone poles would be hard to miss... But last year I was filming a farming harvest with mainly low level flying. There was I think just one telephone pole in that field but while flying sideways parallel to the tractor I came very close to connecting with the pole - gave me quite a shock.

See
and skip ahead to 7:08 ...

Never say never!

All the best, Martin
We're talking about automated flight for mapping, which is a completely different animal from video production. They're not even in the same ball park.

D
 
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My flights vary a lot due to the fact that I film field work being done for our clients and also for our marketing people. This means I sometimes orbit 15 to 20 feet off the ground, or glide in from 100 ft a distance away to a close-in shot of the work being performed. So telephone poles and wires NORMALLY come into play in my work. I had a gig where town officials felt it would be pretty cool to have me to fly around their town and "visit" the annual murals that are painted on various establishment walls throughout the town. That was quite a challenge with many locations having a spider web of telephone and electric wires criss-crossing the town streets. But it was a fun gig.

I hear ya. But as I pointed out to the other guy, "automated mapping" and "video production" have very little, if anything, to do with one another. I assumed your original reply of "...followed by noting on a printout the various poles, wires, and other items I must be aware of for a safe flight" was based on mapping work. Ergo, my reply. Somewhere the conversation got disconnected from "mapping" and digressed to "video production." I used the word "forensics" on purpose, to indicate mapping, inspections and other types of non-creative drone work. But perhaps that was a wrong choice of words?

To get the conversation back on track, my original post was regarding mapping ONLY. Video production requires a completely different pre-flight, flight and post-flight regimen, not to mention a completely different set of piloting skills.

D
 
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We're talking about automated flight for mapping, which is a completely different animal from video production. They're not even in the same ball park.
Hi D,
You are so right. I do both. One is flying and the other is hanging around like a plant stand while the bird takes care of business. 😊
All the best, Martin
 
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Hi D,
You are so right. I do both. One is flying and the other is hanging around like a plant stand while the bird takes care of business. 😊
All the best, Martin

Hehe...that's essentially right. Now if I can just get the bird to charge its own batteries, make sure its own settings are correct, manage video files and create and mail invoices, I can just sit at home and let the bird do ALL the work! HA!

...<;^)

D
 
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My flights vary a lot due to the fact that I film field work being done for our clients and also for our marketing people. This means I sometimes orbit 15 to 20 feet off the ground, or glide in from 100 ft a distance away to a close-in shot of the work being performed. So telephone poles and wires NORMALLY come into play in my work. I had a gig where town officials felt it would be pretty cool to have me to fly around their town and "visit" the annual murals that are painted on various establishment walls throughout the town. That was quite a challenge with many locations having a spider web of telephone and electric wires criss-crossing the town streets. But it was a fun gig.
Same. My clients are ALWAYS asking me to do risky shtuff! Shadows cast by a low sun add another dimension of information that can be gleaned from an aerial photo. I do a lot of information gathering for commercial roofing, and shadows can indicate relative height of elevation changes between roof areas, exhaust fans, HVAC equipment, etc. I have only made maybe 30 3D maps, and I never cared about sunny or cloudy and neither did any of the clients. Apparently it all depends on what the client wants.
 
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the shadows help in location of bases of objects. iv been involved in stereophotogrammetry for a lot of years now, actually over 30 years. i use digital stereo softcopy in the production of topographical maps. when capturing a site for aerial mapping a cloudy day is out of the question. i cant tell you how many times iv flown across long distances only to get over the target and the cloud cover prevented the capture . you can only be as good as the weather forecast for the area of capture. depth perception, when operating a stereo plotter is greatly effected if you have no shadows.
 
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D, your client has legitimate comments, but as I try to explain to my clients, unless the project site is right around the corner, it is very difficult to be able to plan for and acquire images in a certain condition… sunny vs. overcast. And then you must consider their deadline, which means we usually want to fly their project at the earliest opportunity. Of course, acquiring images in either all sun, or all overcast conditions is pretty much a must. But you can improve your deliverable regardless of lighting conditions.

As a surveyor and design engineer, I am my most frequent (and favorite) client. I like mapping in sunny skies so that the shadows identify power poles, signs, fence lines, etc. But I also like that overcast skies yield better terrain mapping when looking for good dtm information. Since I am also the end-user of the orthomosaic I feel I am in a good position to know what helps in either situation.

I spend a significant amount of time editing the orthomosaic, whether shot in sunny or overcast conditions. After creating the ortho, I will go in to Pix4D and create regions around specific objects and replace the mosaic with a portion of a single image. Consider a street sign for example. In the orthomosiac, the sign is often indiscernible. But if you create a region around it, and replace the mosaic with a single image, the sign and post will become clearer. You can see where the post enters the ground, and you can often pick an image that shows the sign face clearly. This does not affect the accuracy of the overall orthomosaic by editing these small areas. But it allows the user to get more information from the ortho.

I also review the point cloud closely to find objects that may not appear in the ortho. They may be completely invisible in the ortho… until you create a region and make the edit.

On a one-mile highway project, I may have 100-200 regions that I have corrected. Pix4D does a decent job of this, but the more regions you create, the longer the processing time gets. It can be a pain, but the end-product is more useful.

If you don’t already, I recommend experimenting with editing the orthomosaic, but add an hour or two to your proposal for this purpose. Best of luck!
 
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D, your client has legitimate comments, but as I try to explain to my clients, unless the project site is right around the corner, it is very difficult to be able to plan for and acquire images in a certain condition… sunny vs. overcast. And then you must consider their deadline, which means we usually want to fly their project at the earliest opportunity.

Exactly. Just last month 3 projects were hours out-of-town and this month we have a project so far away that we're looking at an over-nighter.




Of course, acquiring images in either all sun, or all overcast conditions is pretty much a must. But you can improve your deliverable regardless of lighting conditions.

At this point we're approaching these jobs on a job-by-job basis. Some of the jobs have nothing on the property, which means no fencing or other non-organic items. They often DO have trees and foliage, which cast shadows that seem to impede rendering process. My partner does the Pix4D stuff, and I often hear him complain about shadows. So for those jobs we're still considering cloudy days.



As a surveyor and design engineer, I am my most frequent (and favorite) client.

Touché on that one. My partner and I generally work for one surveyor who actually works for his father's surveying company. I'm in charge of all things drone and work as a 1099 contractor. Despite all the cooks, it's a very amicable relationship. Everyone gets along extremely well. This latest "complaint" is just another variable in the work flow. My business partner is in charge of the job decisions, so he handles all the weather stuff, which is perfect, because it absolved me of that responsibility. If we travel and can't shoot, there is usually some kind of "consolation compensation." But honestly, I can't remember the last time we actually traveled and couldn't shoot. If weather takes a turn for the worst, we usually know the day before. But I digress...


I like mapping in sunny skies so that the shadows identify power poles, signs, fence lines, etc.

Funny...after 4 years of doing this aerial mapping stuff, we are just now discovering this. I think it's because for the first time in our mapping history we hit 3 cloudy jobs in a row. N.M. is notoriously sunny, so 95% of our jobs are shot on sunny days. So it's like the aligning of the planets to get 3 cloudy jobs in a row.




But I also like that overcast skies yield better terrain mapping when looking for good dtm information. Since I am also the end-user of the orthomosaic I feel I am in a good position to know what helps in either situation.

Absolutely. You're very uniquely qualified having your fingers in all facets of the orthomosaic/mapping process. A sort of loose analogy of this has been my sound company. While most audio engineers have their audio skill sets, I've been a professional musician my entire life. This gives me an inside perspective that a non-musician could never have. I often know what musicians want even when they don't. You're sort of like that musician audio engineer.



I spend a significant amount of time editing the orthomosaic, whether shot in sunny or overcast conditions. After creating the ortho, I will go in to Pix4D and create regions around specific objects and replace the mosaic with a portion of a single image. Consider a street sign for example. In the orthomosiac, the sign is often indiscernible. But if you create a region around it, and replace the mosaic with a single image, the sign and post will become clearer. You can see where the post enters the ground, and you can often pick an image that shows the sign face clearly. This does not affect the accuracy of the overall orthomosaic by editing these small areas. But it allows the user to get more information from the ortho.

I also review the point cloud closely to find objects that may not appear in the ortho. They may be completely invisible in the ortho… until you create a region and make the edit.

On a one-mile highway project, I may have 100-200 regions that I have corrected. Pix4D does a decent job of this, but the more regions you create, the longer the processing time gets. It can be a pain, but the end-product is more useful.

If you don’t already, I recommend experimenting with editing the orthomosaic, but add an hour or two to your proposal for this purpose. Best of luck!

Very interesting. I'm passing this information onto my business partner.

Thank you for your uniquely qualified insight. This is good information that I plan on putting to good use. I'll keep you in the loop as to what he says.

D
 
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<stuff deleted to save bandwidth>

If you don’t already, I recommend experimenting with editing the orthomosaic, but add an hour or two to your proposal for this purpose. Best of luck!

Hey Big River;

My partner's response:

"Yeah I’ve done this but the problem is then you can get into seamline issues in the orthophoto which detracts from the overall aesthetic as a base layer. Also going through and editing an Ortho at every t-post along a highway ROW fence sounds like no fun lol."


Thoughts?

D
 

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