# Forum

### Author Topic: Build OrthoMosaic Batch Process Projection  (Read 5275 times)

#### James

• Hero Member
• Posts: 748
##### Build OrthoMosaic Batch Process Projection
« on: February 01, 2016, 11:15:52 PM »
When setting a batch process to build orthomosaics for all my chunks (i have about 25 for this project), it seems to default to a top projection.

I want to be able to do left, right, front and back too.

There is a projection parameter that i can set but this only seems to include geographic projections. There is a 'custom' box but i'm not sure how to create custom projections for left, right, front and back, or if that's the right thing to do anyway.

I shall start working out the python way to do it, and check back here in case there is an easier way before i finish...

Thanks!

**edit** the python was pretty simple and went something like this:

Code: [Select]
`import PhotoScanfront = PhotoScan.Matrix([[1, 0, 0, 0],[0, 0, 1, 0],[0, -1, 0, 0],[0, 0, 0, 1]])back = PhotoScan.Matrix([[-1, -0, -0, 0],[0, 0, 1, 0],[0, 1, 0, 0],[0, 0, 0, 1]])left = PhotoScan.Matrix([[-0, -1, -0, 0],[0, 0, 1, 0],[-1, 0, 0, 0],[0, 0, 0, 1]])right = PhotoScan.Matrix([[0, 1, 0, 0],[0, 0, 1, 0],[1, 0, 0, 0],[0, 0, 0, 1]])doc = PhotoScan.app.documentfor chunk in doc.chunks: if chunk.label.endswith("East"): proj = right elif chunk.label.endswith("South"): proj = front elif chunk.label.endswith("West"): proj = left else: proj = back chunk.buildOrthomosaic(surface=PhotoScan.DataSource.ModelData,blending=PhotoScan.BlendingMode.MosaicBlending,color_correction=False,projection=proj)`
« Last Edit: February 02, 2016, 02:39:44 PM by James »

#### zoos

• Newbie
• Posts: 12
##### Re: Build OrthoMosaic Batch Process Projection
« Reply #1 on: March 02, 2017, 12:03:25 AM »
Hey James

Thanks that really helped me.

But i Do not understand what the Matrix is doing ? Why does it have 4 Values. ItÂ´s not x,y,z than right ?

You would really help me out if you explain.

Zoos

#### James

• Hero Member
• Posts: 748
##### Re: Build OrthoMosaic Batch Process Projection
« Reply #2 on: March 02, 2017, 01:15:34 PM »
I can't claim i entirely understand it myself, but it's a 4x4 transformation matrix which describes translation, scaling, shear and rotation.

I think I probably got the values from Alexey's post here:
http://www.agisoft.com/forum/index.php?topic=1322.msg15758#msg15758

https://www.tutorialspoint.com/computer_graphics/3d_transformation.htm

I think the matrices used for the ortho projection in this case are purely describing the various rotations required for each view.

#### zoos

• Newbie
• Posts: 12
##### Re: Build OrthoMosaic Batch Process Projection
« Reply #3 on: March 02, 2017, 09:14:59 PM »
Thanks James.  Now i get it !!!

have a lovely day

#### mcmigovych

• Newbie
• Posts: 1
• The Cheesy Animation Factory
##### Re: Build OrthoMosaic Batch Process Projection
« Reply #4 on: March 03, 2017, 09:27:50 AM »
For the structure from motion model calculation in PhotoScan, you may want to do the batch processing sometimes. am i Right ?