Hello!
Please find below a description of a bug with loading/saving data:
Step 1. Load a point cloud from a text file (format 'x y z scalar')
Step 2. Save a point cloud to a text file
The problem is a difference between initial and saved scalar field values (see a picture).
It happens when a scalar value is too large (e.g. 17138633).
The difference between initial and saved values is always 1 and it happens only with odd numbers, they are converted to closest smaller even number (e.g. 17138633 -> 17138632)
Scalar field issue
Re: Scalar field issue
In fact it's a known limitation of CC. As we work with 32 bits floating point values internally (to reduce the memory usage) we have a limited precision when dealing with large numbers.
And while this is correctly handled for coordinates or even for the known 'GPS time' field of LAS files, we don't have a backup strategy for the generic case (e.g. ASCII files).
I guess we should add a clear warning about that at least.
And while this is correctly handled for coordinates or even for the known 'GPS time' field of LAS files, we don't have a backup strategy for the generic case (e.g. ASCII files).
I guess we should add a clear warning about that at least.
Daniel, CloudCompare admin
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- Posts: 2
- Joined: Fri May 20, 2016 12:04 pm
Re: Scalar field issue
Thank you for the reply!