[talk-ph] editing admin boundaries of Marikina

[Eugene Alvin Villar]

Hi maning,

What we and Ian do is to decompose the borders as a network of ways. Each
boundary way should only be a dividing line between any two barangays (if
known) and left unnamed and tagged with the lowest (numeric) possible
admin_level. Then the borders surrounding a barangay are collected into a
relation as are the ways surrounding a municipality, city, province, etc.

Example: City A is composed of barangays W, X, Y and Z.

   ,--------,--------,
   |    2   |    4   |
   |1  W    |3       |
   |        |   X   5|
   |--------|        |
   |   8   7|    6   |
   |        |--------|
   |9  Y    |        |
   |        |11  Z 12|
   |  10    |   13   |
   '--------'--------'

Hopefully the ASCII art looks ok. In this example, we have a total of 13
ways all tagged with boundary=administrative. In addition, ways 1, 2, 4, 5,
12, 13, 10, and 9 are tagged with admin_level=6 (city) while the rest with
admin_level=10 (barangay).

Then create relations for each of the barangays:

Barangay W:
type=boundary
boundary=administrative
admin_level=10
name=W
members: 1,2,3,8 (all as blank)

and so on.

Then finally, City A is another relation:
type=boundary
boundary=administrative
admin_level=6
name=A
members: 1,2,4,5,12,13,10,9 (all as blank)

Hopefully this explains everything.

Eugene / seav


On Tue, May 26, 2009 at 6:36 PM, maning sambale
<emmanuel.sambale at gmail.com>wrote:

> Hi,
>
> I am starting to add admin boundaries of Marikina (partly because I
> envy Makati!).
>
> http://www.openstreetmap.org/?lat=14.6442&lon=121.1174&zoom=14&layers=B000FTF
>
> I am now adopting seav's proposal on the admin_levels and using
> relations for aggregating barangay boundaries into Marikina City
> borders.
>
> The admin boundaries around marikina (QC, pasig, san mateo, cainta and
> antipolo) maybe a bit messy right now.  Partly because I am trying to
> understand how to merge marikina barangay boundaries into the existing
> boundaries (please don't touch them for the moment, I promise to
> finish this weekend).
>
> The hardest part is how to tag multiple boundary levels.
>
> for example, the northern border of Barangay Nangka:
> http://www.openstreetmap.org/browse/way/35024130
> admin_level = 10
> boundary = administrative
> name = Nangka
>
> is also the  admin boundary of Marikina and San Mateo
> admin_level = 6
>
> which is also part of the Rizal border
> admin_level = 4
>
> which is also the regional boundary
> admin_level = 3
>
> Whew!
>
> When there are conflicts (in the OSM sense), I decided to treat higher
> admin level (i. e. barangay and municipalities), as a "priority" over
> other admin levels.
> Is this good practice?
>
>
>
> --
> cheers,
> maning
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> ------------------------------------------------------
>
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>



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