V.krige GSoC 2009

v.autokrige: Python porting and wxPython GUI addition

Anne Ghisla's Google Summer of Code 2009 project, mentored by Martin Landa and Michael Barton

Aim of the project

As GRASS presently lacks kriging capability, it is performed via an add-on, v.autokrige, that delegates analysis to R (package automap). This module is written in bash and has the classical autogenerated GUI. The project aims to rewrite the module in Python, creating a new GUI in wxPython that allows the user to refine parameters. I therefore plan to examinate present v.autokrige code and port it into Python, possibly improving it at the same time, and add a wxPython GUI. All time left will be dedicated to addition of further functionality, in respect of the most needed.

State of the art

• Writing the wxPython interface - have a look at it from svn:

svn co https://svn.osgeo.org/grass/grass-addons/vector/v.autokrige2 v.autokrige2

It is now little more than a bare grey square with a statusbar and a title. More to come :)

• Documenting. There are (have been) some GRASS modules that perform kriging, like:
  • v.surf.krige, v.variogram: no longer developed by authors, difficult to port.
  • s.surf.krig: deprecated since GRASS 6 series.
  • scripts including R and spgrass6: are the concrete basis upon which build the module.

I'm also learning kriging theory and examples in Isaaks and Srivastava's "An Introduction to Applied Geostatistics". Great book, indeed.

• Call for users has been done on gfoss.it, grass-it and grass-users, r-sig-geo and r-sig-ecology mailing lists. Thanks to Giovanni Manghi and João Tiago from GFOSS.pt and Giovanni Allegri for user advices, and to Edzer Pebesma, Paul Hiemstra, Ebrahim Jahanshiri, Dylan Beaudette for support on R side.

• Obtained ArcGIS availability for comparison of interface and functionality, because it is AFAIK the widespread tool used for kriging. Also Isats [0] is a valuable source of ispiration for interface design.

Planned Timeline

Draft:

• create a wxPython interface for ordinary kriging. Will follow Humane Interface rules [1].
• integrate R package automap
• midterm deadline: have a working module that performs ordinary kriging.
• integrate more R functions from gstat and geoR, giving the user the choice between gstat and geoR (kriging results vary in respect of implementation)

Weekly reports are available on SoC mailing list [2]

References

• [0] http://www.geovariances.com/software/video-data-investigation-with-isatis-exploratory-data-analysis-ar0353.html
• [1] Jef Raskin, 2000: The Humane Interface: New Directions for Designing Interactive Systems (ISBN 0-201-37937-6)
• [2] http://lists.osgeo.org/pipermail/soc/