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Author Topic: accuracy of digital surface model  (Read 1557 times)

jessica_tay

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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

Jeremiah_ROWE

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Re: accuracy of digital surface model
« Reply #1 on: May 23, 2017, 04:20:02 PM »
Hi Jessica

One of the ways we verify accuracy is to have out field work survey crew capture a series of invisible check shots.

We reference the model initially using the geotagged locations in the EXIF data.

We then mark the GCP and optimize based upon the control points.

The resulting DEM is then exported and loaded into QGIS. The point sampling tool is used to compare our check shot values with the corresponding locations in our DEM.

jessica_tay

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Re: accuracy of digital surface model
« Reply #2 on: May 23, 2017, 05:35:16 PM »
Hello Jeremiah_ROWE,

Thank you for the reply.

But I did not understand why do you mean by referencing the model to the geotagged location.

you mean when you are aligning the photos? you selected by references and not generic?

And by mean of check shots.. what do those shots contain and what values are you comparing?

Thanks for replying.

Jessica