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Topics - jessica_tay

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1
General / Is it possible to build a before and after DEM?
« on: July 27, 2017, 07:39:45 PM »
Hello,

i have taken images of a site before and after the flowering season. And have aligned the photos in separate chunks.

I will probably be using the same GCP for both chunks.

Is it possible to build a DEM for the before and after flowering and is it accurate to see the height of the flowering plants?

Thanks!

Jessica

2
General / is there a way to export exif file?
« on: July 26, 2017, 07:04:44 PM »
Hello,

I have a series of images taken with a drone in tiff format. and i have a separate txt file containing the longitude, latitude and altitude of each image. is there a way to export a exif file from Photoscan?

I tried the export exif button on the reference tab but it said GPS meta data not found.

Does anyone have a suggestion on how to add gps information to the images? i also have the images in raw format.

Thank you!

Jessica

3
General / colour difference after exporting
« on: June 26, 2017, 04:14:04 PM »
Hello all,

i build an orthomosaic with photos taken with an infrared camera and vegetation were supposed to appear red. IƤve attached the screenshot of the orthomosaic as seen in Photoscan.

However, when i exported it as tiff to be analyzed in Arcgis, the colour changes.

Anyone has any experience with exported images to Arcgis and can explain why is there a colour difference? i am not sure if the difference in colour will affect my analysis when I use the different spectral band information for calculating vegetation index.

Regards,
Jessica

4
General / resolutions of Orthomosaic
« on: May 29, 2017, 10:43:50 AM »
Hello to everyone!

I realised that one can set the resolution of the orthomosaic, but if it was left alone, Photoscan will just assign its own resolution.
My question is, does it really become higher resolution if we set it manually? or is there a limit or threshold as to how high res the image can go? If that is the case, the default resolution size set by PS should be the highest resolution?

Thanks! Any explanation is appreciated.

jessica

5
General / accuracy of digital surface model
« on: May 23, 2017, 01:10:55 PM »
Hello all,

is it possible to check how accurate the digital surface model is? (is it in the 'generate report?')

And does having more ground control points helps to improve the accuracy or is there a threshold number where it doesn't improve it further.

Thank you!!

Jessica

6
General / Panorama 360
« on: May 22, 2017, 06:18:26 PM »
Hello,

Recently I started a project taking spherical panorama with the drone. I combined the photos in Agisoft and it come out perfectly but it is a little warped.

I was wondering if Agisoft is able to produce a 360 panorama where I have the option to pan around?

Thanks!

7
General / Orthorectification of photos
« on: April 28, 2017, 12:53:41 PM »
Hello,

I am wondering if the orthomosaic is already orthorectified? if not, how do I do the orthorectification to reduce distortion?

When I export the tif of the orthomosaic into arcgis, it looks a little tilted. I guess by changing the projection, it helps a bit but is there a way to orthorectify the mosaic?

Thank you!

regards,
Jessica

8
General / Accuracy of DEM
« on: April 26, 2017, 04:07:40 PM »
Hello all,
I am trying to create a DEM from images taken from a drone (100m height). the images are references with x,y and z(altitude) information.

My coordinates are in decimal degree and my work area is in germany.

Generation of the sparse/dense cloud and mesh are fine, but when I generate my DEM based on dense cloud or mesh, both results are odd, giving me values in the negative range.

Anyone knows how to correct this?

Thanks!

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