Planar vs Geographic orthomosaic?!

[mrafiei]

HI, I have a question about orthomosaic generation.
 I have a project with 30 hectar area and I want to Build Orthomosaic.
What is the exact different between Planar and Geographic projection in Build Orthomosaic?

Is it correct that when I want to use Geographic projection, I use Local UTM ground control point? or I must to use UTM coordinates?

Please clear me, Thank you very much.

[stihl]

Local means what it says. A local coordinate system. Meaning this has *no* reference to the actual world.

If you want to export a geo-referenced Orthomosaic you must use WGS84 (UTM) or another coordinate system. The one you need to pick is depending on what your customer wants. Communicating about this is vital for correct product delivery.

When you have the option to Build the Orthomosaic on a Planar type projection it means that your project is either not geo-referenced or your project coordinate system is set to local. In this context with planar, Photoscan means that you Build the Ortho based on the bounding box and it's current rotation.

In short; if you want to export a Orthomosaic image that has coordinates assigned for it, you must set a proper project coordinate system first and then export it in this same coordinate system when Photoscan asks you in which projection it should Build or Export in.

[Alexey Pasumansky]

Hello mrafiei,

In case you have any reference points for your project (like coordinates of the camera positions or ground control points) you might want to have an output georeferenced in the same coordinate system, then you need to use Geographic project type and select the coordinate system that corresponds to the system used for the reference points measurement.