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

[sylvain willart]

SOLVED,

example from the "Nord-Pas-de-Calais" region:

############################################
v <- c(237,55,236,58,229,57,214,57,203,55,197,54,187,48,179,46,179,35,180,31,184,26,197,23,201,24,202,31,207,34,213,31,216,37,219,41,228,46,234,47,237,55)

seqx <- seq(1,length(v),by=2)
seqy <- seq(2,length(v),by=2)

vx <- c()
for (j in seqx) {
vx <- c(vx,v[j])
      }
vy <- c()
for (j in seqy) {
vy <- c(vy,v[j])
      }
plot(vx,-vy)
polygon(vx,-vy,border="red")
############################################

thanks for your tips,

Sylvain
Now, I just have to read it using maptools...

2010/3/3 sylvain willart <sylvain.willart at gmail.com>:
> Hi
> 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:
> http://www.insee.fr/fr/ppp/bases-de-donnees/donnees-detaillees/duicq/accueil.asp
> 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
> generates...
>
> 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...)
>
> sylvain
>
>
> 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
>>
>