I have 400 cities on an excel spreadsheet. Not all different; all in
the Chicago area. I want to plot the "center" of all these datum,
using free software (mapping?). Purpose - find the location that is
equally convenient for the members of our group. Multiple instances
of one city should count as multiple instances. Desirable to print
out a map showing the concentration by city and the "center". |
Request for Question Clarification by
endo-ga
on
09 Jun 2003 18:23 PDT
Hi,
Thanks for your interesting question, I'm not sure such software
already exists, but I haven't searched extensively yet. One thing that
could be possible, would be to look up the coordinates of each city,
using a website such as multimap.com then just calculate the mean of
the longitudes and latitudes. You could then derive a precise location
from the coordinates. Someone could write software to do the lookup
automatically from your Excel spreadsheet or from a CSV file, but this
would take at least a couple of hours.
May I suggest that you just make the venue in an easily accessible
place and a big well-known area? It is usually quite easy for people
to get to places that are well known, and if the place is near a
highway/rail station, then it's even simpler.
Thanks.
endo
|
Clarification of Question by
ej1216-ga
on
09 Jun 2003 19:14 PDT
Endo:
Thanks. I could not find any software but thought there could be,
given all the work done on correct store sites etc.
I was just curious to see if I could come up with the center - we do
have our meetings in a reasonably central location.
EJ1216-ga
|
Request for Question Clarification by
endo-ga
on
09 Jun 2003 19:57 PDT
Hi,
It is possible, but would require some coding. At first I thought it
wouldn't be possible to find a free database containing city names and
coordinates, but then fell on this:
http://geonames.usgs.gov/pls/gnis/web_query.gnis_web_query_form
and this:
http://n1.cs.fiu.edu/cgi-bin/tfstate.cgi?s=IL
The first state is pretty useful because you can enter the state, for
example Illinois, choose all populated places and ideally it would
return the results to you. But there are over 4000 results for that
request and that page will only display up to 2000 results. I also
thought that it would be possible to just do a wildcard search after
each letter of the alphabet, but this is taking extremely long for the
database to process so it is not feasible.
Luckily there is a solution even though it might take some time. That
would be to search for populated places, county per county in
Illinois, using the drop down boxes (or a script), then copy/paste the
information into a file, then write a simple program to query the file
for the coordinates of each city, and compute the center.
It certainly is doable if you're still interested.
Thanks.
endo
|
Clarification of Question by
ej1216-ga
on
09 Jun 2003 21:23 PDT
Endo:
Thank you, but since I was curious and not in need of the result, it
isn't worth the effort.
Regards,
ej1216-ga
|
