Topics

1

General / DTM X DSM - orthomosaic precision

« on: June 16, 2020, 07:03:06 PM »

In order to measure buildings, do DTM and DSM have different accuracy? or just the view that sometimes DSM appears on a wall

2

General / diference in measurement on DTM and DSM.

« on: August 29, 2019, 04:28:14 PM »

Is there a difference in measurement (precision) when DTM is mosaic instead of DSM in an urban environment?

3

General / What is the best way to align photos with GCP?

« on: May 27, 2019, 02:12:47 PM »

What is the best way to align photos with GCP?

1 - Align in the low, insert the GCP, deselect the photos and select only the GCP and align again in the high.

2 - Align in high, insert the GCP, unselect the photos and optimize.

3 - Align at high, insert GCP and optimize alignment with selected cameras and GCP.

Ps: Drone without RTK, and GCP with RTK

4

General / workflow for urban areas

« on: May 17, 2019, 12:24:28 AM »

Does anyone have an workflow without distortion using DEM or DTM?

- Over / sidelap capture (in the log do I use height relative to the ground or change the height of the pixhawk?)
- Accuracy for alignment, densecloud
- optimization and cleaning

I'm exaltively testing but I never get to a perfect project or close to it.

I'm using a Samsung nx mini to capture the images

5

General / Classification of ground points problem

« on: May 14, 2019, 04:40:22 PM »

I'm trying to generate a DTM to create an orthomotic, but some ground points in the dense cloud are not being sorted at all. By the way I realize they are a bit shifted down.

I'm using a new camera on a fixed wing, can it be something related to that? Does anyone have any suggestions for workflow or something I can try?


I used:

over/sidelap? 80 / 70
Picture Quality: 1.8>
Alignment: Medium (40,000 / 10,000)
Dense Cloud: Medium (agressive)

I was cleaned the sparse cloud with error on reprojection and accuracy


I already did another project and I never had this problem. Tks

6

General / Asign image and accuracy !

« on: March 12, 2019, 09:30:04 PM »

When I use the "assign image" tool to correct faults in the orthomosaic, do I compromise the accuracy of distances?
because some photos seem to diminish or increase the buildings

thaks

7

General / Orthophoto problem

« on: April 17, 2018, 06:34:21 PM »

Good afternoon, the orthophoto generated has some cuts, in the case below comes to cut a house.

I'm generating orthophoto from Dem (generated by the grounds points of the dense cloud).

PS: I'm not using control points, but I optimized the camera after it has aligned.

overlap 80% / 50%

Something I'm doing wrong? follows the settings used in the image.

8

General / Two questions - Number of Markers and Alignment

« on: December 17, 2017, 09:38:52 PM »

I have two questions regarding a large project.

I will make about 11 pieces of 600 32-megapixel photos.

1- By manual, I must have 10 accurate markers. Do I need 10 in the whole project or 10 per chunk?

2 - What is the best way to generate the final orthophoto (I am going to do from the DEM), what kind of alignment (for chunks) should I use or how should I do it? (is there any tutorial with this?)

Sorry my english

9

General / Problem with builds in orthophoto

« on: December 07, 2017, 05:31:17 AM »

I am generating the orthophoto from the DEM, but in higher buildings I have this problem, I have tried in several ways, but I could not find a solution.

Is there any tool that allows me to manually correct or some trick that does not work?

sorry my english

Tks