Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - jessica_tay

Pages: 1 [2]
Hello Madekwe,

I am also interested in mapping vegetation cover. Was wondering it you now have a recommendation for the configuration of the dense cloud? should I use a moderate or aggressive filtering?

My UAV is flying at an altitude of 50m. and I am interested in creating a high resolution image to be able to identify some plants from the image itself, so it is ideal to have a good orthomosaic of it.



General / Re: Ortomosaic
« on: May 03, 2017, 06:05:18 PM »
Hello Smikelz,

your photos from the UAV should come with a flight log containing the x,y and z values and they can be imported directly into Agisoft.

After you add the photos into agisoft, you can align the photos (workflow tab). then you build dense cloud, mesh then orthomosaic. Then you can export it as tif to be used in arcgis.

There are a few tutorials on Youtube to follow, or agisoft also has a manual that you can follow to create you orthomosaic.

good luck!


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

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!


General / Re: Accuracy of DEM
« on: April 28, 2017, 12:51:10 PM »
to those who replied,

Thank you so much! I managed to build the DEM after using all your comments and input. :)


General / Re: Accuracy of DEM
« on: April 28, 2017, 11:00:48 AM »

Thanks for the suggestion. But I should also remove the Z values? since there are flight altitude and not the elevation?

and yes, i realised that after aligning the photos, the points are not horizontal.. instead it is lying diagonally in the bounding box. Do you have any idea how to solve it? my coordinates are all taken in WGS84, in decimal degrees.


General / Re: Accuracy of DEM
« on: April 27, 2017, 09:47:22 PM »
Hi Jan,

Thanks for the reply.

I realised that the images from the drone doesn't have the gps metadata.. so i dont really know how to get elevation data? Does it come with the flight log as well? maybe it is possible to extract the elevation from a previous elevation model.

I will try to define my gcp with the xyz data and try again.

Thanks anyway.


General / Re: Accuracy of DEM
« on: April 27, 2017, 04:02:35 PM »

I've included an image of the data that I am working with.

Can anyone tell me what is wrong with it? that the DEM is wrong?

i've created a dense cloud, then made the DEM with it. But it generate that dem..


General / Re: Accuracy of DEM
« on: April 27, 2017, 03:35:06 PM »
Hello SAV,

Thank you for your reply. the z coordinates are already adjusted based on the planned flight, which are all around 99m to 100m.

I do have 5 ground control points but it did not make the DEM better..

How do I extract the AGL from the geotagged photos?


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?


Pages: 1 [2]