[R-sig-Geo] newbie questions

[Alex Mandel]

tom sgouros wrote:
> tom sgouros <tomfool at as220.org> wrote:
> 
>> Dan Putler <dan.putler at sauder.ubc.ca> wrote:
> 
>>> Er, what exactly is your data? Do you have data that is linked to zip
>>> codes and you want to do a "thematic" (choropleth) map of the data? Do
>>> you have point data (say a lat/lon values), and want to plot the points?
>>> Given what you've said, hard to figure out how to get you going in the
>>> right direction.
>> The data is mostly from past elections, so it's vote totals or
>> demographic data within some district.
> 
> I should have also said that I have both SHP files and E00 files to
> describe the boundaries of the districts, but have no feeling about
> which I should prefer or why and I wonder if anyone else does.  The SHP
> files come with an XML description that seems not to be used by grass.
> The E00 files maybe come with a description of their own projection,
> while I had to identify a projection to specify it to grass, but
> otherwise I don't know why one would be better or worse.
> 
> Thanks,
> 
>  -tom

For your purposes the shp will be easier to work with, the E00 file
contains the same information and something called Topology which is
irrelevant to this particular use. The XML file is metadata, none of the
software involved here directly uses it, the projection information is
stored in the .prj file for shapefiles.
SHP is more widely recognized by software and in most cases E00 just
gets converted to it at some point anyways.

Alex