[R-sig-Geo] newbie questions

[tom sgouros]

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


> 
> Google tells me that choropleth is the name of precisely the kind of
> thing I'm trying to make, thank you for expanding my vocabulary today.
> 
> Is there a name for the bar graph kind of thing?  (Here's an example:
> http://www.turbosquid.com/FullPreview/Index.cfm/ID/346428 )
> 
> Thank you,
> 
>  -tom
> 
> > 
> > On Sun, 2009-11-15 at 22:30 -0500, tom sgouros wrote:
> > > Raphael Saldanha <saldanha.plangeo at gmail.com> wrote:
> > > 
> > > > Hi Tom!
> > > > 
> > > > I'm a geographer and R enthusiast too, but what I can say is: R is a great
> > > > software to statistics. The final production of maps, although it's
> > > > possible, it's simple and faster made with GIS softwares, like GRASS,
> > > > Quantum GIS or ArcGIS.
> > > 
> > > This is exactly my quandary.  I have some data I want to map, and I have
> > > no idea how to do it and none of the introductions I've found speak to
> > > what I thought was a pretty simple task.
> > > 
> > > I first thought maybe I should use a GIS, since it's geographic data,
> > > but all the GIS documentation I can find is about how to analyze data
> > > that's already available.  There are no end of Grass examples using this
> > > North Carolina dataset that comes with the installation, but I don't
> > > live in North Carolina and I don't want to analyze their data.  I want
> > > to analyze mine, but I can't figure out how to get it in, and that's
> > > what I'm using R for.
> > > 
> > > If you are telling me there is a simpler way to do this, I am all ears
> > > (eyes), especially if it uses grass or qgis which I can afford, and not
> > > Arc, which I can't.
> > > 
> > > Queries of GIS guys told me that what I need to do is to get my data
> > > into a shape file first and then a GIS can help me display it, so I
> > > turned to R for that.  Was I wrong there, too?
> > > 
> > > Most of the data I want to map is not currently in any format at all.
> > > It's just numbers I have.  I have shape files for the geography and I
> > > want to apply my numbers to those shapes and draw maps in color, and I
> > > also would very much like to draw the 3d kind where the geographic area
> > > is raised up according to some value.  (I don't know if there's a name
> > > for this.)  I tried to use a spreadsheet to get my data attached to the
> > > shapes, but as soon as I realized I needed to do a join of my data and
> > > the shape file data I began to look for alternatives.
> > > 
> > > I know that I'm working at a very low level here, but in addition to
> > > Roger's advice before about how to get R to cooperate, I would be
> > > grateful for any advice such as you've provided about what exactly R is
> > > good for in my task and what a GIS is good for.  Your note advances me
> > > down the field quite a bit, but if there's more, I'd be interested to
> > > know it.
> > > 
> > > Many thanks,
> > > 
> > >  -tom
> > > 
> > > 
> > > 
> > > > 
> > > > My tip is: organize data with spreadsheet and GIS softwares, import (as
> > > > shapefile, if possible) in R and make your statistical analysis and
> > > > statistical columns of data, export to another shapefile and manipulate the
> > > > final map in GIS softwares.
> > > > 
> > > > I repeat, it's possible make all these steps in R, and generate great maps,
> > > > but the most simple way is above. Personally, I use R to make the final maps
> > > > only when I have to produce a long series of simple maps.
> > > > 
> > > > I think the best way is the integration of GIS software with R, each one
> > > > with his specialty.
> > > > 
> > > > 
> > > > King regards,
> > > > 
> > > > Raphael Saldanha
> > > > BRAZIL
> > > > saldanha.plangeo at gmail.com
> > > > 
> > > > 	[[alternative HTML version deleted]]
> > > > 
> > > > _______________________________________________
> > > > R-sig-Geo mailing list
> > > > R-sig-Geo at stat.math.ethz.ch
> > > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> > > > 
> > > 
> > > 
> > -- 
> > Dan Putler
> > Sauder School of Business
> > University of British Columbia
> > 
> 
> 
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