[R-sig-Geo] maptools - what happened to Map2poly?

[Roger Bivand]

On Tue, 16 Mar 2010, Matt Fitzpatrick wrote:

> Hello - Can anyone refer me to the function that replaced map2poly?

(note - Map2poly(), please refer to functions by their correct names - 
the function discarded attribute data from an imported shapefile (S3 
class "Map") to make a list of polygons. The data representation is not 
robust nor supported in further development).

That function was long deprecated (a warning was shown that the underlying 
representation would be withdrawn from the user namespace). See otherwise 
many replies to questions about this over the last three months, for 
example:

https://stat.ethz.ch/pipermail/r-help/2010-March/231949.html

https://stat.ethz.ch/pipermail/r-sig-geo/2010-February/007610.html

https://stat.ethz.ch/pipermail/r-sig-geo/2010-February/007611.html

https://stat.ethz.ch/pipermail/r-sig-geo/2009-December/007253.html

etc. As you will see, many of the questioners also use HTML mail, not text 
mail, so perhaps both reading the posting guide and searching the 
archives, as well as reading warning messages, might be a good idea.

The sp package has been in place for five years now, so removing direct 
access to its inadequate antecedents in maptools isn't unexpected. Legacy 
scripts can be adapted as shown in the replies; replacing read.shape() 
with readShapeSpatial() should be sufficient for most uses as the plot() 
method for the deprecated S3 "polylist" class has similar arguments to the 
plot() method in the sp package for objects inheriting from the S4 
"SpatialPolygons" class. If need be, use the ::: operator to access 
commands in maptools no longer in the user namespace.

Alternatively, stay with an antiquated version of maptools, your choice.

Roger

>
> Thanks,
> Matt
>
> <http://www.al.umces.edu/people/faculty/mattfitzpatrick.htm>
>
>
> 	[[alternative HTML version deleted]]
>
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-- 
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