Hello all:
I was referred to this list when I asked a question on the r-help list
about mapping. Unfortunately, I seem to be a little late to the party,
and a couple of weeks of monitoring the traffic have left me no more
enlightened than I was before, since it seems that the questions asked
are generally at a level I haven't approached yet.
I am an R user who wants to learn to make maps. I have been using R to
analyze data associated with cities and towns in my area, and would
like to figure out how to get that data onto a map, but I'm having a
hard time seeing where to begin.
Assuming that I'm starting pretty much from zero, where can I start
reading in order to learn what is possible? (And what to use to achieve
it.)
I'm also a little confused about whether people use R as a GIS stand-in,
or whether they use some GIS package, and then use R as an adjunct. If
the latter, can anyone recommend GNU or other freeware GIS packages to
learn about? How about books to learn about them with?
Many thanks for your indulgence,
-Tom
On Saturday 24 November 2007 02:04:17 pm Tom Sgouros wrote:
Hi Tom, sorry to hear that you haven't discovered what you were looking for
yet. Here are some comments / suggestions.
Hello all:
I was referred to this list when I asked a question on the r-help list
about mapping. Unfortunately, I seem to be a little late to the party,
and a couple of weeks of monitoring the traffic have left me no more
enlightened than I was before, since it seems that the questions asked
are generally at a level I haven't approached yet.
R is one of those applications which takes some time to get into. I have been
a graduate student for a couple years now, and it took three attempts to get
over the initial "activation energy" required for me to feel comfortable with
R. That said, persistence was really the key factor in getting there.
I am an R user who wants to learn to make maps. I have been using R to
analyze data associated with cities and towns in my area, and would
like to figure out how to get that data onto a map, but I'm having a
hard time seeing where to begin.
Now that you are familiar with working in R, it might be a good idea to become
familiar with basic GIS concepts. There are a number of open source tools
which can be used for GIS work, and quite a large community in the form of
mailing lists / IRC channels. There are a number of books which should be
coming out in the next couple of months which cover the wide range of open
source GIS software.
Assuming that I'm starting pretty much from zero, where can I start
reading in order to learn what is possible? (And what to use to achieve
it.)
Most of what I have learned about spatial statistics in R has been from a
collection of books on R, R newsletter articles, and misc. online tutorials.
Here is a link to some tutorials which illustrate using GRASS and R:
http://casoilresource.lawr.ucdavis.edu/drupal/node/438
I'm also a little confused about whether people use R as a GIS stand-in,
or whether they use some GIS package, and then use R as an adjunct. If
the latter, can anyone recommend GNU or other freeware GIS packages to
learn about?
Since *most* R operations occur in memory, GIS operations on large datasets
are best done in a dedicated GIS app like GRASS. For most of my work GRASS,
GMT, PostGIS, R, and Mapserver are a tough combination to beat.
How about books to learn about them with?
See above suggestions. There should be two books out soon which are dedicated
to opensource GIS applications- I would keep an eye out for these.
Cheers,
Dylan
On Saturday 24 November 2007 02:04:17 pm Tom Sgouros wrote:
Hi Tom, sorry to hear that you haven't discovered what you were looking for
yet. Here are some comments / suggestions.
Hello all:
I was referred to this list when I asked a question on the r-help list
about mapping. Unfortunately, I seem to be a little late to the party,
and a couple of weeks of monitoring the traffic have left me no more
enlightened than I was before, since it seems that the questions asked
are generally at a level I haven't approached yet.
R is one of those applications which takes some time to get into. I have been
a graduate student for a couple years now, and it took three attempts to get
over the initial "activation energy" required for me to feel comfortable with
R. That said, persistence was really the key factor in getting there.
I am an R user who wants to learn to make maps. I have been using R to
analyze data associated with cities and towns in my area, and would
like to figure out how to get that data onto a map, but I'm having a
hard time seeing where to begin.
In addition to Dylen's helpful reply, you might like to review the
"Spatial" Task View on your local CRAN mirror, and the Rgeo website linked
from the Task View. There are many possible choices, but using the classes
and methods in the sp package may suit you. They are reviewed in a note in
R News (2005 (2), pp. 9-13), in an online e-seminar at:
http://www.geog.uu.nl/~pebesma/wun/
and in courses and tutorials such as:
http://www.bias-project.org.uk/ASDARcourse/
Hope this helps,
Roger
Now that you are familiar with working in R, it might be a good idea to become
familiar with basic GIS concepts. There are a number of open source tools
which can be used for GIS work, and quite a large community in the form of
mailing lists / IRC channels. There are a number of books which should be
coming out in the next couple of months which cover the wide range of open
source GIS software.
Assuming that I'm starting pretty much from zero, where can I start
reading in order to learn what is possible? (And what to use to achieve
it.)
Most of what I have learned about spatial statistics in R has been from a
collection of books on R, R newsletter articles, and misc. online tutorials.
Here is a link to some tutorials which illustrate using GRASS and R:
http://casoilresource.lawr.ucdavis.edu/drupal/node/438
I'm also a little confused about whether people use R as a GIS stand-in,
or whether they use some GIS package, and then use R as an adjunct. If
the latter, can anyone recommend GNU or other freeware GIS packages to
learn about?
Since *most* R operations occur in memory, GIS operations on large datasets
are best done in a dedicated GIS app like GRASS. For most of my work GRASS,
GMT, PostGIS, R, and Mapserver are a tough combination to beat.
How about books to learn about them with?
See above suggestions. There should be two books out soon which are dedicated
to opensource GIS applications- I would keep an eye out for these.
Cheers,
Dylan
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
Hi Tom:
Good question. The information on GIS/Mapping and R (as well as other
open-source software tools)
is somewhat decentralized, but there is a great deal of high-quality
information available if you
know where to look -
One place that you might start is the CRAN task view for spatial data
analysis:
http://cran.r-project.org/src/contrib/Views/Spatial.html
Another is a web site that we are developing here at the Center intended
to educate ecologists
here and elsewhere on spatial analysis / mapping / GIS techniques:
http://nceas.ucsb.edu/scicomp/SolutionsCenter.htmlhttp://nceas.ucsb.edu/scicomp/SciCompDocuments.html
These sites have many links to spatial data analysis resources;
we are adding to these sites on a regular basis.
Another very good site is maintained by the Soil Resource lab at UC Davis:
http://casoilresource.lawr.ucdavis.edu/drupal/taxonomy_dhtml (site map)
Best Regards,
Rick Reeves
Tom Sgouros wrote:
Hello all:
I was referred to this list when I asked a question on the r-help list
about mapping. Unfortunately, I seem to be a little late to the party,
and a couple of weeks of monitoring the traffic have left me no more
enlightened than I was before, since it seems that the questions asked
are generally at a level I haven't approached yet.
I am an R user who wants to learn to make maps. I have been using R to
analyze data associated with cities and towns in my area, and would
like to figure out how to get that data onto a map, but I'm having a
hard time seeing where to begin.
Assuming that I'm starting pretty much from zero, where can I start
reading in order to learn what is possible? (And what to use to achieve
it.)
I'm also a little confused about whether people use R as a GIS stand-in,
or whether they use some GIS package, and then use R as an adjunct. If
the latter, can anyone recommend GNU or other freeware GIS packages to
learn about? How about books to learn about them with?
Many thanks for your indulgence,
-Tom
Hello all:
I almost hesitate to write and thank you all for the helpful replies,
because good ones keep appearing in my inbox, and who would want to put
a stop to that?
But my gratitude overcomes my cupiditude, so thank you all very much for
the pointers.
-Tom
Hello all:
I've gotten two requests asking me to post a summary of the answers I
got to my question. The answers were dense, and will take me a bit to
assimilate, but here's my early attempt at a review. People will, I
hope, correct where I'm screwing it up.
The overall message was not to confuse R with a GIS system. Use a GIS
to manipulate and display geographical data; use R to analyze it.
I found this helpful:
Most of what I have learned about spatial statistics in R has been from a
collection of books on R, R newsletter articles, and misc. online tutorials.
Here is a link to some tutorials which illustrate using GRASS and R:
GRASS came up frequently, as did QGIS as freeware GIS systems to try.
I'm not sure how to judge between them, but I figure frequency of
mention isn't a bad start.
In which case, I recommend you look at uDig
(http://undig.refractions.net), QGIS (www.qgis.org), and/or gvSIG
(http://www.gvsig.gva.es/index.php?id=gvsig&L=2), which are open source,
desktop GIS packages. If you are in the latter case, you will want one
of the desktop products mentioned above (and GRASS will also be a
possible option, http://grass.itc.it), and will you also want to look
into the sp, maptools, PBSmapping, and spatstat R packages.
I've been looking into sp, of course, but haven't yet found the
introduction that will take me from the ground floor up to its dizzying
heights. What seems true of it is something I've noticed about a lot or
R: there is stellar reference material available, but not much in the
way of usage guides. The working theory seems to be that you pick that
up while you're earning your statistics PhD.
Along those lines, the following is a rich vein of information, but most
of it presumes you already know what you want:
You might like to review the "Spatial" Task View on your local CRAN
mirror, and the Rgeo website linked from the Task View. There are many
possible choices, but using the classes and methods in the sp package
may suit you.
On the other hand, I think the following will be quite helpful, since it
contains examples of maps similar to those I would like to create:
It seems that a lot of my confusion is in and around the division of
software labor, so this explanation has set me on what I think is the
right course:
Thanks very much for the reply. I think a lot of my confusion is in not
knowing where the boundaries fall between the different applications.
Can you tell me roughly the division of labor among the software you
mentioned?
Sure. I use GRASS / PostGIS anytime I need to work with GIS data: raster,
vector + attributes, etc. Importing, merging, subsetting, modification, and
summarizing are best done within a GIS (I think). When I need graphical
summaries (box and whisker plots and such) I will import the data into R and
go from there. In other words, most of the heavy lifting of pushing pixels
and vertices is done in the GIS. All of the analysis is done in R: summaries,
hypothesis testing, and prediction using models. This nice thing about the
GRASS-R bindings is that you can predict from GRASS data, and send the
predicted values right back into a GRASS raster/vector .
Lately I have been using R to produce some maps -- although mainly maps of
purely vector data like thematic maps. The high quality PDF output from R
makes for an ideal platform for producing press-ready vector graphics. Check
out the spplot() function in the sp package for plotting a mixture of
vector / raster data. When plotting raster data out to a PDF, be careful
about generating gigantic files -- each pixel can be represented with a
little rectangle, and for large grids can result in massive PDF files.
I will try and post an examples of this.. in the mean time check out Roger's
sp website- it should be in the manual page for the sp package. There are
numerous mapping examples in there.
For more complex maps I tend to favor GMT. Examples:
http://casoilresource.lawr.ucdavis.edu/drupal/node/130
So my plan right now is to install the maptools package so I can follow
some of the course materials at bias-project.org.uk, and to install
GRASS or QGIS in the hope that one of them can help me convert the
ESRI-format political boundary map files available from my local
planning offices into something that R can munch on. (I'm pretty sure
I'll be back seeking all your indulgence sometime then.) For the moment,
I expect that the mapping I'll do will be via maptools, since the
immediate need is pretty rudimentary. I still know nothing about GRASS
and QGIS (but will soon) so don't yet know whether I can produce
print-quality (hi-res, vector graphic axes and fonts) maps from them,
but I hope so. (And I'll be checking out GMT, too.)
So that's what I learned this weekend. Many thanks again for all the
advice.
-tom
tom sgouros <tomfool at as220.org> wrote:
Hello all:
I almost hesitate to write and thank you all for the helpful replies,
because good ones keep appearing in my inbox, and who would want to put
a stop to that?
But my gratitude overcomes my cupiditude, so thank you all very much for
the pointers.
-Tom
--
------------------------
tomfool at as220 dot org
http://sgouros.comhttp://whatcheer.net