4 Square mile ranch

[Serfy]

Hey guys, I'm a cinema pilot but have done photogrammetry on occasion.
A good friend owns a 4 square mile ranch in Texas and is looking to get a high quality map/photogrammetry of their parcel and have asked me if I can do it. I've only done SFD properties.

A couple questions:
I assume a Mavic 3E would be most efficient travel wise and rental wise.
Approximately how many hours / days would a Mavic 3E take to do an area this large? In the past I flew at 100'-150' AGL. (there are some hills which I'd need to be higher than so it might be 200')
What is a reasonable price to do this?

Thank you!

 

[jaja6009]

What is your friend hoping to get from this?
Is this just for visualization of the property does he want absolute accuracy to include elevations for contours.

Some points to think about

Below 80 70 overlap (You can go lower, but with such a large project I'd be careful since you do not want to do a reshoot.

• At 250ft AGL and ~ 2cm GSD you will have about 9 hours of flight time if flying @ 25 mph
  • This was for flying a 2 mile by 2 mile box which you won't be flying
  • You will have to divide up the area into segments to keep LOS
  • When making segments you will have to ensure overlap of the segments further increasing time
  • You will have to travel to and setup at each new flight area increasing time
  • You could use one of the terrain following features if the area has varying elevations
  • Here are other times @ AGL
    • 300' AGL 5+ hours ~ 15,000 images and 2.5 GSD
    • 350' AGL ~ 6 hours ~ 10,500 images and 2.9 GSD
    • 400' AGL ~ 5 hours ~ 8,000 images and 3.3 GSD
• Accuracy
  • With a GSD of ~ 2cm you could realistically get 2 to 6 cm absolute accuracy
  • If covered in vegetation those areas elevations will be suspect but roads, trails and bare earth will be good for elevations
  • Do you have access to an RTK service or base?
    • Without those how will you layout control points for checks and also a few GCPs?
    • Even with them, how will you layout control points in such a large area
  • When attempting such a large area over possibly days, what if there are some changes to the mapped area? This could affect alignment
• Processing
  • In the 2 mile by 2 mile box Pilot 2 had ~ 22000 images for the 250'AGL missions. When dividing into segments again you will increase your image count so it will be more. How will you process this massive amount?
  • You can make separate chunks in Agisoft and Pix4D and then combine
  • Even with chunks, that is a ton of processing time

In my opinion, a quadcopter is not the correct tool for such an ambitious project. Since you mention renting, try a Wingtra or a fixed wing with a full frame camera.
And while you are at it rent a GNSS rover with a subscription to an RTK service and hope you have cell phone coverage in the area or you will have to also rent another GNSS base and either find an NGS monument or use OPUS to create your own point.

Pricing?

Since you do not sound like a PLS, this pricing is between friends and I could not possibly come up with a price as I do not know you or the other person.

adm geomatics (member) may chime in. He will be of more help with this as he does this professionally for a living with a large construction company.

 

[adm_geomatics]

Hey guys, I'm a cinema pilot but have done photogrammetry on occasion.
A good friend owns a 4 square mile ranch in Texas and is looking to get a high quality map/photogrammetry of their parcel and have asked me if I can do it. I've only done SFD properties.

A couple questions:
I assume a Mavic 3E would be most efficient travel wise and rental wise.
Approximately how many hours / days would a Mavic 3E take to do an area this large? In the past I flew at 100'-150' AGL. (there are some hills which I'd need to be higher than so it might be 200')
What is a reasonable price to do this?

Thank you!

A mission of 4 sqmi (640 acres) would be close to 2.5 hours of actual flight time at 200ft AGL, so add the time it would take for multiple setups to maintain VLOS. Make sure to use real-time terrain following. Travel to and from the site, data management time, processing time and deliverables prep time are things typically included in our budgets. I typically charge $75/hr travel time and $175/hr site time and $100/hr computer time.

Travel - 2hrs - $150
Site time - 4.5hrs (allotting general logistics for setup, checkpoints, and breakdown) - $787.50
Computer time for appx 6K images - 10 hours - $1000

Total - Somewhere around $2K
Friends and family discount 15%

 

[Serfy]

A mission of 4 sqmi (640 acres) would be close to 2.5 hours of actual flight time at 200ft AGL, so add the time it would take for multiple setups to maintain VLOS. Make sure to use real-time terrain following. Travel to and from the site, data management time, processing time and deliverables prep time are things typically included in our budgets. I typically charge $75/hr travel time and $175/hr site time and $100/hr computer time.

Travel - 2hrs - $150
Site time - 4.5hrs (allotting general logistics for setup, checkpoints, and breakdown) - $787.50
Computer time for appx 6K images - 10 hours - $1000

Total - Somewhere around $2K
Friends and family discount 15%

This is what I needed, just a ballpark number.

 

[Cornsipper]

4 square miles is 2560 acres. 1 square mile is 640 acres.

 

[adm_geomatics]

4 square miles is 2560 acres. 1 square mile is 640 acres.

Thanks for catching that. My new estimate would be:

Travel - $150
Site - $1300
Computer - $1700

$3150

 

[SteveBCH]

Thanks for catching that. My new estimate would be:

Travel - $150
Site - $1300
Computer - $1700

$3150

I'm curious why you wouldn't set ground control points and targets for such a large area if doing photogrammetry. Thanks.

 

[adm_geomatics]

I'm curious why you wouldn't set ground control points and targets for such a large area if doing photogrammetry. Thanks.

Does the client require it?