[R-sig-Geo] Status of gpclib license

[Edzer Pebesma]

Nicholas,

this is unlikely; if true, the author would have done well to update his 
software page http://www.cs.manchester.ac.uk/~toby/alan/software/ and 
the corresponding wikipedia entry, 
http://en.wikipedia.org/wiki/GPC_General_Polygon_Clipper_Library

Even (some) universities can these days be very picky with licensing 
when someone at the administration level smells money revenues from 
software developed by one of the employees; they might claim that 
anything produced by the employees in work time is owned by the university.

Best wishes,
--
Edzer

Nicholas Lewin-Koh wrote:
> Hi Roger,
> I thought I remembered that at some point you had contacted the author
> of gpclib and gotten permission to release the package under gpl. Has
> that changed or is senility completely catching up with me.
>
> Nicholas
>
>
>   
>> Date: Fri, 15 Jan 2010 20:00:30 +0100 (CET)
>> From: Roger Bivand <Roger.Bivand at nhh.no>
>> To: rick reeves <reeves at nceas.ucsb.edu>
>> Cc: "r-sig-geo at stat.math.ethz.ch" <r-sig-geo at stat.math.ethz.ch>
>> Subject: Re: [R-sig-Geo] Alternate methods: Polygon Algebra / Polygon
>> 	Overlay with R Spatial objects..
>> Message-ID: <alpine.LRH.2.00.1001151932080.18465 at reclus.nhh.no>
>> Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
>>
>> On Fri, 15 Jan 2010, rick reeves wrote:
>>
>>     
>>> Hello List:
>>>
>>> I have been reviewing techniques within R for performing the GIS-like 
>>> operation 'polygon algebra' (computing the union and intersection of 
>>> polygons within two SpatialPolygonDataFrame objects). The goal is to 
>>> combine two polygon data frames, to produce a new polygon data frames 
>>> that contain the union or intersection of the two input sets.
>>>
>>> Thus far, the only method that I have found for this is the 
>>> combinePolys() method within the PBSmapping package. The PBSmapping 
>>> routines work well, but require the transformation out of the 
>>> SpatialXXXDataFrame classes.
>>>       
>> For union, aka dissolve, see unionSpatialPolygons() in maptools. Perhaps 
>> better, don't look yet. The underlying problem is the license of the 
>> gpclib package, which should be avoided. The reason for attention to 
>> package licenses is that CRAN is getting very large, and taking 
>> responsibility for distributing non-free software through package 
>> dependencies needs to be automated. So GPL and other free packages should 
>> not depend on or suggest non-free packages, because users (including 
>> commercial users) may not be aware that they are using packages with 
>> non-free licences. Some of these users already block the installation of 
>> free packages with "upstream" non-free dependencies, and more will do so 
>> in the future.
>>
>> One solution is the R-Forge rgeos package, which I'm working on.
>>
>> https://r-forge.r-project.org/projects/rgeos/
>>
>> Before long, again thanks to Uwe Ligges and others, we should have a 
>> working production line for Windows binary packages with GEOS 3.1.1 
>> included. Linux distributions have binaries or can install from source; 
>> OSX has a Kyngchaos framework to handle the external dependency on GEOS.
>>
>> rgeos has unionSpatialPolygonsGEOS(), which, when rgeos reaches CRAN,
>> will 
>> be used by maptools in unionSpatialPolygons() if rgeos is available.
>>
>> GEOS has the necessary functions to do what you would like, but someone 
>> has to write the R and C code and add it to rgeos. The current 
>> SpatialLinesIntersections() function returns a SpatialPointsDataFrame 
>> object with the IDs if the intersecting lines, but more is needed for 
>> SpatialPolygons intersection. The handling of the data frame variables is 
>> far from obvious too - just copying across count or rate variables isn't 
>> appropriate. Most likely the handling of the data slots would have to be 
>> done by hand for the new SpatialPolygons objects based on the
>> intersecting 
>> ID values.
>>
>> R-Forge has the possibility for new developers to join projects ...
>>
>> Hope this helps,
>>
>> Roger
>>
>>     
>>> The overlay() method within sp seems like the best routine for this job as it
>>> performs intersection operations on pairs of Spatial objects, but it
>>> does not appear to operate on two SpatialPolygonDataFrame objects.
>>> So I have not tried to use it for this.
>>>
>>> Do other packages contain polygon algebra routines that operate on the 
>>> Spatial classes?
>>> If not, are there any alternatives to the PBSmapping methods?
>>>
>>> Thanks,
>>> Rick R
>>>
>>>
>>>
>>>
>>>       
>> -- 
>> Roger Bivand
>> Economic Geography Section, Department of Economics, Norwegian School of
>> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
>> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
>> e-mail: Roger.Bivand at nhh.no
>>
>>
>>
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>>
>> End of R-sig-Geo Digest, Vol 77, Issue 13
>> *****************************************
>>     
>
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-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster 
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de 
http://www.52north.org/geostatistics      e.pebesma at wwu.de