[OSM-newbies] Administrative boundaries

[John Deters]

Don't move the tags to try to make them display.  It's easier to fix once
you find out that display is based on population.  I've fixed some city
names that weren't rendering properly by setting their population tag to the
latest values from Wikipedia.  (It bugged me that New York didn't appear at
zoom level 4.)

For the USAians, I've found a way to query the Census data to retrieve
population and lat/long data for every "place" in my state, but I have not
used it to update the database. (Frankly, I don't know how.)  If you'd like
to get the data, go to: 
http://factfinder.census.gov/servlet/DatasetMainPageServlet?_lang=en&_ds_nam
e=DEC_2000_SF1_U&_program=DEC

Pick Custom Table.  I picked "Place" for geographic type and then my state,
and then All Places, then Add.  For "Select a table", pick P1 Total
Population and click Go, then check Total and click add.  Back up in the
table selection box, scroll to the bottom to G001. Geographic Identifiers,
then click Go again, and check the boxes for "Place", "Internal point
(latitude)" and "Internal point (longitude)" then click Add.  (Class code,
description code and size code may be of interest as well, but I didn't mess
much with them.)  Now click Next, then Show Result.  If you want the data in
a better format, click Print/Download and you can save the queries, or the
data in an Excel spreadsheet or other format such as CSV.

If you navigate to "Data Sets with Custom Tables", you can click "Clear all
selections" to really fix screwups.  If you just navigate to Geography, you
can change the state to generate another list.  (You can even pick all
places for several states and keep adding them, but I bet there's a limit
somewhere.)


-----Original Message-----
From: James Ewen [mailto:jewen at shaw.ca] 
Sent: Sunday, November 09, 2008 10:35 PM
To: newbies at openstreetmap.org
Subject: Re: [OSM-newbies] Administrative boundaries

If you don't tag for the renderers, then you need to change the
renderers for the tags! There's a problem with that though, because if
you change the renderer, it affects everyone world wide. If you simply
change the admin_level that you use, it will only affect your area.

So, in Canada where everything is far apart, use admin_level 2 for
provincial borders, but in an area like Belgium, where I can fit the
whole country on screen at zoom level 8, provincial borders are set at
admin_level 6. It would make more sense to allow the local users to
determine what zoom levels certain features should show up at in their
area, rather than trying to make a global list that works for
everyone.

I guess what I'd like to see is a way to be able to tag other items
with optional zoom level extents. One of the problems I have here is
that the City of Edmonton with >750,000 people doesn't get labeled
until you're in really close (zoom 8). At zoom 5, Canada is a blank
canvas as far as any cities are concerned. At zoom 6, Fort
Saskatchewan (15,000), Spruce Grove (19,500), and Leduc (17,000) names
get rendered, but the provincial capital remains hidden.

The solution offered by others is to move the name the City of Spruce
Grove out of the way so Edmonton can be displayed. That not only
sounds like tagging for the renderers, but that also means that I
would have to tag an area a couple miles outside the City of Spruce
Grove with the tag for the city name. Being able to put an optional
display level tag would solve this issue.

James