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Author Topic: export orthophoto, bounding box and pixel size  (Read 7126 times)

JanS

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export orthophoto, bounding box and pixel size
« on: August 27, 2011, 11:45:53 PM »
Dear forum,

Export orthophoto seems to have some issues resulting in slightly smaller pixel sizes than entered in the textbox.

e.g. when I enter 1 m as pixel size and take care the bounding box min/max limits are also rounded to 1 meter, the resulting pixel size is 0.999899 m. Bounding box margins are also slightly off.

When instead I use the max. image size textbox instead of pixel size textbox, I can avoid the issue. e.g. I want a 1 m pixel size and have an area from 536200 to 537200 (1000m) in X and 25600 to 26000 in Y (400 m), I enter 1000 m as max image size and the resulting image has exactly 1 m pixel size. In this case however, the resulting image goes from 25600 to 25999 in Y (399 instead of 400 pixels).

Note: in my case, both the model and the export coordinates were in UTM 31 N.

Best regards,

Jan

Alexey Pasumansky

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Re: export orthophoto, bounding box and pixel size
« Reply #1 on: August 29, 2011, 11:06:43 PM »
Hello Jan,

Thanks for the reporting, we'll check it.
Best regards,
Alexey Pasumansky,
Agisoft LLC

Alexey Pasumansky

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Re: export orthophoto, bounding box and pixel size
« Reply #2 on: August 30, 2011, 02:42:28 PM »
Hello Jan,

We've checked the described case. Pixel resolution in PhotoScan orthophoto export dialog means the physical dimensions but not any projected values (e.g. in UTM) that have slight difference between the original dimensions and projected ones.

But we will consider the option to enter resolution based on current projection.
Best regards,
Alexey Pasumansky,
Agisoft LLC

JanS

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Re: export orthophoto, bounding box and pixel size
« Reply #3 on: August 31, 2011, 12:05:25 PM »
Thanks Alexey,

This would certainly help us since many of our clients have requirements for exactly defined pixel sizes.
I understand now that the current implementation is not a but, although changing it would make PhotoScan behave more conform to mainstream GIS/remote sensing software (PCI, ArcGIS, ERDAS and the like)

Best regards,

Jan