Area outline

Hey

i was thinking about making a status page about the ways in Faroe Islands
what was done and what was missing
i have an official list(table) with name,postalnumber and other data about all the ways in Faroe Islands
i tought i could just match that list with the name node in the osm way data
but forgot that the same name is used in different cities/towns what ever(we are only 48.000 people)

but then i thought about that i have imported all the house numbers along with the postal code into osm
and then i thought how do i figure out the area of a postal number

like if i have a bunche of nodes how do i get an polygon of the outline ?

then i could have an postalnr area and check if that way was witin that postal area
so do any of you have any link/suggjestion

OSM way data
name
collection of lat/lon

official data
name
one node of lat/lon
postal number

ahhh fuck i am stupid
if there are more than one official way with the same name i can just check the proximity of the lat/lon of the official data to the osm data
if it is a realy big difference then it is not the same way

Eureka

Sorry for the rambling
but i still would be interesting in the questin about figuring out the outline of a bunch of nodes

/LiFo

User:randomjunk made a nice postcodes map for the UK

This is taking point data from freethepostcode.org, and figuring out polygons from this. Source code is linked

For the compare itself :
Look at http://osm.gt.owl.de/Strassenliste/map-nordrhein-westfalen.html (click on a town to get the list of the town) which is a for the german state NRW.
Each town got his own border-relation and the streets in OSM are compared to a official list of each town.
You could ask Flo how he did this and get the code.