Mapping Accuracy with IP

[DigitalDrone]

Hi Everyone,

I have an Inspire Pro and have some drone mapping questions, if you wouldn't mind answering.

1) If I were to map out an area with my IP, what would the accuracy be within (without GC or RTK)?

2) Would flying lower or higher improve measurement accuracy?

3) Would different focal lengths/lenses improve accuracy?


Also, for what applications/sectors would I be able to provide a mapping service to where minimal accuracy would be sufficient enough (mapping without GC or RTK)?

For what Sectors would I need to provide a drone mapping service using GC or RTK?


Thank you and I look forward to your replies.

 

[RMartin]

Hi Everyone,

I have an Inspire Pro and have some drone mapping questions, if you wouldn't mind answering.

1) If I were to map out an area with my IP, what would the accuracy be within (without GC or RTK)?

2) Would flying lower or higher improve measurement accuracy?

3) Would different focal lengths/lenses improve accuracy?


Also, for what applications/sectors would I be able to provide a mapping service to where minimal accuracy would be sufficient enough (mapping without GC or RTK)?

For what Sectors would I need to provide a drone mapping service using GC or RTK?


Thank you and I look forward to your replies.

I recall reading somewhere that the accuracy of the I1 was between 30cm - 5m uncorrected. The best accuracy uncorrected I had during testing was around 2m. Any sector that requires exact measurements would require GCPs and/or RTK results (construction, survey, ect...) I set my GCPs with a Trimble Geo 7X GPS unit on an RTK network and my accuracy is about 1-1.5cm for large-acre tracks on land.
You will get better resolution with an X5 over and X3. With better resolution you can fly at a higher altitude and cover a large area in less time. I fly at 80' AGL with an X3 (12mp) for construction/survey work. I could probably increase that altitude to 100-120' AGL (or maybe more) with an X5 (20mp?) and spend less time in the air.

It boils down to what type of service you plan on providing. If you decide to go the mapping/survey route, a decent GPS unit will run you around $2400.00USD with mapping grade software (centimeter accuracy) installed. Survey grade software for the same unit will probably add another $1000.00 USD to the total. We get our RTK feed from Trimble for no charge. I operate the UAS and the GPS off of an Alcatel Hotspot with excellent coverage in the field for roughly $30.00USD per month for unlimited data.

Finally you also need to consider image processing software; Pix4D, Correlator3D UAV, AgiSoft....whatever fits your budget. I know there are more options available too. And don't forget an PC that can handle your processing....and make sure that the GPU will operate with the software package you choose. Some will operate fine on OpenGL while others require both OpenGL and OpenCL support in order to work.

Hope this helps some.

 

[bluelight.support]

Also, for what applications/sectors would I be able to provide a mapping service to where minimal accuracy would be sufficient enough (mapping without GC or RTK)?

For what Sectors would I need to provide a drone mapping service using GC or RTK?

Where are you based - as I know in the US to offer services like this you would need to be licensed, in the UK its different

 

[RMartin]

I work for a university located in the Dallas-Ft.Worth area in Texas, and yes, I am a licensed sUAS pilot with the FAA and a certified geographic information systems analyst as well. I am not a State-licensed surveyor (and I have no desire to be). To complicate matters all of our land falls within Class D airspace which requires additional waivers/authorization to fly.

I am not sure about other sectors. Real estate is another popular use for UAS flights in this area, but there are so many local, regional, and international airports in the area that getting permission to legally fly can be a painful process.

 

[bluelight.support]

I could probably increase that altitude to 100-120' AGL (or maybe more) with an X5 (20mp?) and spend less time in the air.

I fly at 100ft with a Olympus 12mm on an X5 (now I2 so X5S), 150ft with the 17mm, 250ft with the 25mm and 400ft with the 45mm all give great results.

if i want to do a large area the 12 or 17 at a higher altitude works well with a reduction of around 05>1cm ground resolution. Depends on your application and number of batteries!!

 

[DigitalDrone]

I recall reading somewhere that the accuracy of the I1 was between 30cm - 5m uncorrected. The best accuracy uncorrected I had during testing was around 2m. Any sector that requires exact measurements would require GCPs and/or RTK results (construction, survey, ect...) I set my GCPs with a Trimble Geo 7X GPS unit on an RTK network and my accuracy is about 1-1.5cm for large-acre tracks on land.
You will get better resolution with an X5 over and X3. With better resolution you can fly at a higher altitude and cover a large area in less time. I fly at 80' AGL with an X3 (12mp) for construction/survey work. I could probably increase that altitude to 100-120' AGL (or maybe more) with an X5 (20mp?) and spend less time in the air.

It boils down to what type of service you plan on providing. If you decide to go the mapping/survey route, a decent GPS unit will run you around $2400.00USD with mapping grade software (centimeter accuracy) installed. Survey grade software for the same unit will probably add another $1000.00 USD to the total. We get our RTK feed from Trimble for no charge. I operate the UAS and the GPS off of an Alcatel Hotspot with excellent coverage in the field for roughly $30.00USD per month for unlimited data.

Finally you also need to consider image processing software; Pix4D, Correlator3D UAV, AgiSoft....whatever fits your budget. I know there are more options available too. And don't forget an PC that can handle your processing....and make sure that the GPU will operate with the software package you choose. Some will operate fine on OpenGL while others require both OpenGL and OpenCL support in order to work.

Hope this helps some.

Thank you for all the info and your time.

I guess, what I want to know is what type of customer can I provide a mapping service to where cm accuracy isn't important to them and to whom would it be important. I just need to clear up what my possibilities and limitations are with using my inspire pro for drone mapping without GCP and RTK.

I'm mostly thinking about providing stock pile measurements and 3D modeling.

 

[DigitalDrone]

I fly at 100ft with a Olympus 12mm on an X5 (now I2 so X5S), 150ft with the 17mm, 250ft with the 25mm and 400ft with the 45mm all give great results.

if i want to do a large area the 12 or 17 at a higher altitude works well with a reduction of around 05>1cm ground resolution. Depends on your application and number of batteries!!

Hi and thank you.

How do you make these calculations of accuracy?

 

[RMartin]

I fly at 100ft with a Olympus 12mm on an X5 (now I2 so X5S), 150ft with the 17mm, 250ft with the 25mm and 400ft with the 45mm all give great results.

if i want to do a large area the 12 or 17 at a higher altitude works well with a reduction of around 05>1cm ground resolution. Depends on your application and number of batteries!!

I know that the X5 series has improved capabilities and would be a fine addition but the next major purchase is going to be focused on an M210 RTK with a Z30. I would like a dual battery solution to give me more flight time. All I have to do is pitch it right.....and hope....and maybe hold my breath...

 

[bluelight.support]

but the next major purchase is going to be focused on an M210 RTK with a Z30. I would like a dual battery solution to give me more flight time.

Dont waste your time - the RTK will NOT pass information from location from flight controller to embed into the JPG file - it is only for actual position accuracy like the M600.

 

[RMartin]

Dont waste your time - the RTK will NOT pass information from location from flight controller to embed into the JPG file - it is only for actual position accuracy like the M600.

That goes without saying LOL. I only rely on the positional data I gather by GPS or Total Station. Everything else is just for informational purposes only.

 

[RMartin]

Thank you for all the info and your time.

I guess, what I want to know is what type of customer can I provide a mapping service to where cm accuracy isn't important to them and to whom would it be important. I just need to clear up what my possibilities and limitations are with using my inspire pro for drone mapping without GCP and RTK.

I'm mostly thinking about providing stock pile measurements and 3D modeling.

3D modeling would be a place to start. Even for volumetric measurements I would think that you would need a reliable degree of accuracy in order for the numbers you gather to be valid. Real estate would be another option as would infrastructure inspection with more experience piloting a UAS.

 

[Droneyboy]

3D modeling would be a place to start. Even for volumetric measurements I would think that you would need a reliable degree of accuracy in order for the numbers you gather to be valid. Real estate would be another option as would infrastructure inspection with more experience piloting a UAS.

Municipal Park and Recreation Boards like to have Orthorectified maps of their parks for planning purposes. I place a white 4foot by 10 foot white plastic table cloth(you can get at Lowes or a party store on a roll) out in an area easily seen from the air and use it for scale in the finished photo. There are a number of Apps to set up the flight. I use Dji GSPro, Drone Deploy and MapPilot. If under 200 images averaging 12 mp each, Maps Made Easy does a good job of stitching images together free. When Maps Made Easy can't do it then Drone Deploy Can. Both of these can be upgraded to accept GCPs and then add Data Mapper, Pix 4D and Correlator 3D and you have lots of choices out there for finishing higher accuracy maps. 250 feet AGL is a sweet spot for a decent Ortho Map with an I2/x5s combo. 100 to 150 feet for cm accuracy(.4 inch). some software will go as small a GSD as you can provide. Some are limited in their output.
I,m still learning. I haven't honed in on the best for me yet.
It has been fun trying them out. I had to get used to the bird doing everything on its own. The last 3 flights, after set up , I tapped once to fly the whole mission without touching any controls on the RC. At first I felt compelled to land it myself but not any more. The I2 has worked flawless for me so far.

 

[bluelight.support]

When Maps Made Easy can't do it then Drone Deploy Can

Can you explain a little more what you mean here - as I always thought that maps made easy was the better app.

 

[Droneyboy]

Can you explain a little more what you mean here - as I always thought that maps made easy was the better app.

Yes......I was doing a job for a municipality. They wanted night photos to evaluate lighting in their township.( I am 107 cert and have a COA for night flight.). I sent in my geo referenced photos to MME 4 separate times and their software just couldn't handle the dark between the light on the images. First time in to Drone Deploy and got a perfect map.

I use both of them. I'm trying Propeller too($). 3D Correlator is in the running too. I'm looking at pay as you go or monthly pay programs so I can line jobs up......skip a month or 2 ........and so on. I work w a small civil engineering firm so can get GCP easily and save them field time for topo. And get paid too.

 

[bluelight.support]

Yes......I was doing a job for a municipality. They wanted night photos to evaluate lighting in their township.( I am 107 cert and have a COA for night flight.). I sent in my geo referenced photos to MME 4 separate times and their software just couldn't handle the dark between the light on the images. First time in to Drone Deploy and got a perfect map.

Got you - the Map Pilot IOS App is far superior to the drone deploy app - I only use the IOS apps to collect the data and ALWAYS use in house software for processing and GNSS processing. Sim Active I rate very highly and have done a lot of work with them. I also use Agisoft Photoscan Pro and 3D Survey. Pix 4D I hate lol. The online systems dont give you the control for high end work in my humble opinion, and I dont think propellor will either. For people who are just getting involved in the sector and want a one-fit solution these services might work, however when you start looking at external GNSS points for GCP and check points, and link in with traditional workflow, its so much easier and safer to be able to change and tweak locally knowing what you've done !

 

[bluelight.support]

250 feet AGL is a sweet spot for a decent Ortho Map with an I2/x5s combo

which lens are you using for this ?

 

[Droneyboy]

which lens are you using for this ?

DJI 15 mm(30 equivalent on full sized sensor)

When you say Simactive ...is that Correlator 3D?
I'm very interested in Correlator 3D. Propeller gave us very useful information and accurate but when I inquired about pricing I lost interest. Data Mapper allows you to enter GCPs individually or import as a csv. File.however we have to convert metric elevations to feet. You don't have that problem.
It's all good.
I'll try the Agisoft and Simactive. Thanks for the info.

 

[bluelight.support]

When you say Simactive ...is that Correlator 3D?

Yes.

Our main lens is the Olympus 12mm which is an extremely sharp lens!

 

[Ranger Bob]

Bluelight; may I ask your opinion on which of these is the most suitable stock lens for mapping - the DJI 15mm lens supplied with the I1 Pro, or the supplied lens on the X4s? I'm trying to push for an Inspire for mostly aerial still and mapping work but it will be unlikely I would have enough for extra lens or the other cameras. I would be looking to pass on the data for post-processing in Pix4d before loading into ArcMap.

Thanks

Bob

 

[bluelight.support]

Bob I go from processing straight into Arcgis Pro now and bypass map - but my process allows this, and the Pro is a nice software package if part of your subscription.

A choice between a 16mp m4/3 sensor and the 1" 20pm sensor on the x4s is very difficult. the x4s is a smaller sensor but is a sony rx100 sensor which we know is excellent. Added to this the mechanical shutter is a bonus.

We only went for the X5S as i got a very good deal from a member on here.

What are you looking at mapping, what quality and what size, as that will have a massive bearing on what lens to go for ?