CloudCompare forum

Hi Daniel,

As always, thanks for your hard work. This is a great creation, cloud compare.

I have 4 questions;

1. Alignment Necessary?: If my clouds are in the same coordinate system, do I need to align them before I use cloud to mesh? I'm trying to compare the performance of my proposed method of topographic data collection, to a UAV derived data set. I feel that aligning them before running the distance computation would artificially improve the C2M results....do you agree with my logic?

2. Statistics of Results: I'm using the cloud to mesh comparison, and it seems to have worked well.
I understand there isn't really a report associated with the tool that will tell me about the results? Is that right?
I'd like to have a go at the results in terms of general stats, max, mean, etc, etc.
I thought I could export to excel, but my cloud is >2m points, which is above the limit of an excel sheet.
Basically I'd like quantitative results to report, and to accompany the visualization of the distance.

3. Error estimates: The software reports the distances acquired in the c2m tool, but is there any error estimates that can be reported?

4. Rasterization: I want to bring my resultant c2m distances into arc map. I know from past discussions with you (under an account I can't recover - I used the "forgot my password" option, but it can't find my email address. however when I register a new account with that email, it says it's already in use....I used another address and here I am....incase this bug is of interest) that you're not super familiar with arc map. I'd like to output my results as a rasterized tiff. I wonder if rasterizing the c2m results are resampling them (results are not uniformly spaced, rasters are) there by introducing small error. This error is I'm sure very minimal, but I wonder if there is a way to know the error?


Thanks in advance,
Lindsay

1) Yes, you shouldn't align the entities in this case.

2) Some pieces of information are in the Console. And you can get them otherwise via the 'Scalar field' section of the cloud properties (you'll be able to get the min and max values of the current scalar field) and you can also call the 'Edit > SF > Compute Stat. Params' tool to compute the mean distance and the standard deviation.

3) What kind of errors are you referring to?

4) You'll have to consider the fact that several points may be averaged inside a single cell when you rasterize the cloud (not sure what will be the best merging option in this case). Otherwise the 'error' for each projected point can't be greater than half the cell size multiplied by sqrt(2) I guess?

This all makes sense, thanks Daniel!