#199 Clipping grid with polygon loses rows/columns of grid data

[Jason]

There seems to be an issue with...

saga_cmd shapes_grid 'Clip Grid with Polygon'

...in that the resulting grid is missing one row on the top and one column on the right-hand side. Calling this command repeatedly with the same grid and shapefile will result in an additional row and column missing for each iteration. Thanks!

[Jason]

Volker,

Both issues (199 and 200) appear in version 2.1.4 as well.

Testing this took some time because it appears that many of the command
line parameters were renamed ('grid_gridding - Inverse Distance Weighted'
and 'grid_tools - Resampling' to name two) in the latest version. These
minor version parameter renamings have become a real nuisance for us. By
the way, where are the change logs kept?

Regards,
Jason

On Fri, Nov 14, 2014 at 4:55 AM, Volker Wichmann reklov_w@users.sf.net
wrote:

Hi,

could you please try to reproduce the problems with SAGA 2.1.4 (the same
applies to bug #199)? There have been changes to the polyclipper library
and the SAGA code since 2.1.2.

Thanks!

• [bugs:#200] http://sourceforge.net/p/saga-gis/bugs/200 Shapes Union
  sometimes leaves bad polygons in results*

Status: open
Group: v2.1.2
Created: Thu Nov 13, 2014 05:53 PM UTC by Jason
Last Updated: Thu Nov 13, 2014 06:11 PM UTC
Owner: nobody

There seems to be an issue with...

saga_cmd shapes_polygons Union

...in that it sometimes leaves "partial" polygons in the resulting
shapefile.

Specifically, we use this combine multiple (2+) shapefiles together in the
form:

A ∪ B => AB
AB ∪ C => ABC
etc.

Our shapefiles were Saga Grids that been run through...

saga_cmd shapes_grid 'Vectorising Grid Classes'

They typically have 20-50 shapes per file, and the resulting 'unioned'
file had about 220 shapes. The problem we noticed was that sometimes the
shapefile ABC contained shapes that overlapped other shapes and had at
least one NULL Name column in the DBF file.

We tried changing the order of the 'unioning' process and were able to
make it work properly about half the time. In the end, I was able to strip
these bad polygons out of the shapefile by looking for the NULL Name
columns. Thanks!

---

Sent from sourceforge.net because you indicated interest in
https://sourceforge.net/p/saga-gis/bugs/200/

To unsubscribe from further messages, please visit
https://sourceforge.net/auth/subscriptions/

[Volker Wichmann]

Ok, thanks for the confirmation. It would be great if you could attach a small sample (dataset and module settings) to each ticket in order to facilitate the debugging process.

Changelogs and other release information (e.g. saga_cmd compatibility) are available here: http://sourceforge.net/p/saga-gis/wiki/SAGA%20Release%20Information/

Regarding the parameter interface changes: believe me, I'm not very happy about them too and we are doing our best to avoid these. But we are a small team and we are focused on development, so there is basically no minor SAGA release, even if the version numbering might suggest this. BTW, who is "us"?

[Volker Wichmann]

I've just fixed this in svn trunk: http://sourceforge.net/p/saga-gis/code-0/2346/