Feature request #2731: Show residual in georeferencer in map units (if possible) - QGIS Application - QGIS Issue Tracking

Feature request #2731

Show residual in georeferencer in map units (if possible)

Added by Marco Hugentobler over 14 years ago. Updated over 7 years ago.

Status:	In Progress
Priority:	Low
Assignee:	mmassing -
Category:	C++ plugins/Georeferencer
Pull Request or Patch supplied:	No	Resolution:
Easy fix?:	No	Copied to github as #:	12791

Description

The following patch shows the residuals in the gcp table in map units where possible and in pixels else. Because interpretation about the gcp errors is easier with map units, so the patch converts pixels->map units for linear transformation and helmert. For the other transformations, conversion to map units is not so straightforward, therefore they are kept in pixels.

100518_georef.diff (6.1 KB) Marco Hugentobler, 2010-05-18 06:37 AM

100519_georefpatch.diff (15.6 KB) Marco Hugentobler, 2010-05-19 02:19 AM

History

#1 Updated by Marco Hugentobler over 14 years ago

Added improved version of the patch. The transform parameters are now shown in the status bar, fixed update of georef transformation when enabling/disabling gcps in the table, fixed pdf report layout

#2 Updated by mmassing - over 14 years ago

Status changed from Open to In Progress

Applied in 4d46f190 (SVN r13553) - thanks, Marco.

I'll leave the ticket open for now, because I'd eventually like to add this functionality for
the higher order transform types (linearization via jacobi matrix or numerical approximation of
the derivatives), and also a config option to choose the desired units.

I think the latter is useful because reporting residuals in pixel units shows if residuals
are in the ballpark of input discretization, whereas map units are useful to better get an estimate of absolute error.