[R] how to import map data (maptools?) from a html set of 'coords'

sylvain willart sylvain.willart at gmail.com
Wed Mar 3 14:32:27 CET 2010

thanks for your reply,
I'll try to better explain my request...
the data do not come from a file with a specific extension, this is
just some lines I copied pasted from a source html file

The web page is:
it displays an (interactive) map of France with all the regions

to access the source: edit/source , or Ctrl+U in a web browser

By the middle of the html source file, there is an html object called
map (<map> ... </map>) with a set of coordinates representing the
polygons of each region,

These coordinates are just location of points: x1,y1,x2,y2,x3,y3...
that draw polygons. They are not proper longitude or latitude and
their "origine" is just the corner of the image the html file

I am aware those are not "real" geographic data (That's why I didn't
post my question to sig-geo, it looks more like a problem of
graphics), but these are the coordinates one need to "draw" a map (and
eventually import it to a more specific package like spatstat)

So, what I would like to do is: using those coordinates to draw such a
map, and eventually use that map for distance or area calculus (which
do not need to be extremely precise...)


2010/3/3 Michael Denslow <michael.denslow at gmail.com>:
> Hi Sylvian,
> On Tue, Mar 2, 2010 at 1:15 PM, sylvain willart
> <sylvain.willart at gmail.com> wrote:
>> Dear R users,
>> I would like to draw map and import it in maptools/spatstat packages.
>> The 'raw data' I have come from a web page (<map>...</map>) and are
>> basically a list of coordinates of a polygon.
>> I would like to know how to import them in R; I checked the maptools
>> packages, but all the examples use existing .dbf files.
>> I just have a (serie of) text file(s) looking like this:
>> For example, for the French Region Burgundy:
>> <area  href="region.asp?reg=26" shape="poly" title="Bourgogne" alt="Bourgogne"
>> coords="208,121,211,115,221,113,224,115,225,120,229,122,232,128,251,125,255,
>> 130,256,136,266,138,268,148,267,154,263,160,267,168,267,180,262,
>> 175,256,178,254,184,248,184,243,187,237,187,232,185,234,181,227,
>> 171,216,171,212,166,211,155,208,149,208,135,211,132,213,125,208,
>> 121">
> It is not clear (to me) from your example what kind of file this is.
> Maybe XML, it does not look like GML. readOGR() in the rgdal package
> may be a better route to explore, but you need to determine what file
> structure is first.
>> any idea welcome,
>> sylvain
>> (If anayone is interested with that type of data, they're available at
>> the INSEE website
> I can not easily find an example on this site. Perhaps you could
> provide a direct link to the file. Lastly, I suspect that the
> r-sig-geo mailing list would get you some better answers.
> Michael
> --
> Michael Denslow
> I.W. Carpenter Jr. Herbarium [BOON]
> Department of Biology
> Appalachian State University
> Boone, North Carolina U.S.A.
> -- AND --
> Communications Manager
> Southeast Regional Network of Expertise and Collections
> sernec.org
> 36.214177, -81.681480 +/- 3103 meters

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