search

qissue-bot / QGIS

QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS)
http://qgis.org
GNU General Public License v2.0
0 stars 0 forks source link

Show residual in georeferencer in map units (if possible) #2719

Open qissue-bot opened 5 years ago

qissue-bot commented 5 years ago

Author Name: Marco Hugentobler (Marco Hugentobler) Original Redmine Issue: 2731, https://issues.qgis.org/issues/2731

Original Assignee: mmassing -

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.

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: Marco Hugentobler (Marco Hugentobler) Original Date: 2010-05-19T00:22:34.000Z

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

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: mmassing - (mmassing -) Original Date: 2010-05-23T03:52:09.000Z

Applied in commit: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.