HELP!!

[millennium_falcon]

Hi,

My company has recently purchased agisoft photoscan professional and we would like to clarify some questions we have about the software. We are a survey company and are testing out drone imaging for the production of orthomosaics and DEMS that will be used for mapping and surveying. With this in mind we are interested in achieving the highest accuracy ortho images possible. We are looking for approximately 3 cm horizontal accuracy and 5 – 10 cm vertical accuracy in the images and DEMs.

We have been following your tutorial on creating orthomosaics and DEMS (with ground control points) available freely online, however we have a few questions regarding tools and parameters to ensure we get the highest accuracy data possible. We are currently using your software in conjunction with a UAS operating at approximately 400 ft altitude. Our optical sensor is a Sony Alpha 6000 equipped with a 20 mm lens.  Our survey areas can vary in size up to 300 square miles, which we will be breaking down into more manageable 4 square mile areas. 
What would be the minimum amount of ground control points that you would recommend for a 4 square mile area, keeping in mind that we are looking for centimeter accuracy.

Based on the camera reference settings to optimize camera alignment, we will be surveying our ground control points to within 2 cm of accuracy. Can you suggest the appropriate reference settings to ensure camera accuracy?
With regards to the optimize camera alignment window, could you provide additional explanation as to the various available check boxes and settings and how to select the appropriate parameters.

We will be digitizing features off the imagery within ArcMap. Can you provide any insight on compression settings in the export mosaic window to ensure that we have accurate and usable data preferably in one orthomosaic (rather than in blocks).

Assuming that we are able to achieve the accuracy we are aiming for with Agisoft Photoscan Professional, we will be interested in purchasing an additional license. Can you provide us a quote for one with Agisoft Photoscan Professional license?

We appreciate any help you can provide us on these topics.

[JMR]

[...] we are interested in achieving the highest accuracy ortho images possible. We are looking for approximately 3 cm horizontal accuracy and 5 – 10 cm vertical accuracy in the images and DEMs.

[...] operating at approximately 400 ft altitude. Our optical sensor is a Sony Alpha 6000 equipped with a 20 mm lens. 

Sounds just fine.

[...]up to 300 square miles

Sounds to manned aviation. Flying that large area at UAV legal altitude will mean a huge number of photos and passes and require a totally insane number of GCP's if you want to keep that accuracy all over the area, I'd say you will require about one GCP /25 photos.
As an alternative I'd recommend you a PPK dual frequency GNSS system on board of your drone. We have created a 60grams solution for this and it's currently being used in large National Parks in Latin America but with a Cessna due to the large area of interest. If you are interested, please send us a request at info@drobit.es

Best,
GEOBIT