Correct curvature check and respect options

[CarawaySeed42]

The local curvature check was incorrectly implemented and only worked in certain circumstances.
Changes to crg read and write were necessary to properly respect the global curvature check option.
The curvature check also did not follow the specification and the specification incorrectly stated the default global curvature options.
This implementation leaves the curvature check working as it was intended
but the intention is up for discussion.

Resolves: #8

Signed-off-by: Patrick Kuemmerle patrick.kuemmerle@3d-mapping.de

[3Dbastian]

Considerations regarding this pull request:

• Please see also general idea of the local curvature check in Local Curvature Check #8
• The proposed changes were necessary, since the newly implemented local check only worked under certain situations
• Actually the Flags WARN_GLO and WARN_LOC are no warnings but errors, if they are activated the Writing and Plotting of a CRG fails in the Matlab API causing a Matlab error, Reading works
• There are four possible combinations of setting the flags
  • WARN_GLO = 0 and WARN_LOC = 0 -> no Check
  • WARN_GLO = 1 and WARN_LOC = 0 -> only Global check = Default
  • WARN_GLO = 0 and WARN_LOC = 1 -> not useful -> proposal if this is used WARN_LOC is also set to 0 (alternative would be to set WARN_GLO to one)
  • WARN_GLO = 1 and WARN_LOC = 1 -> both checks are activated
• crg_test_curvature.m example was fixed, please note, the road used for that example is only for showing the curvature vs width effect, but is not intended to have meaningful height values

[3Dbastian]

• in my opinion the local check is a legitimate feature
• the changes are necessary to make it fully functional for Matlab API

[CarawaySeed42]

Also see commit 8261069 to understand why statements regarding the curvature check option flags are phrased the way they are.

If
WARN_GLO == -1 (default if not specified in file) then it is implicitly treated as unequal to 0 -> do check
If
WARN_LOC == -1 (default if not specified in file) then it is implicitly treated as smaller or equal to 0 -> do not check

[asadekasam]

OpenCRG CCB 09.02.2026: @jorauh will review it.