[Tagging] Bridges and layers

Nathan Edgars II neroute2 at gmail.com
Tue Jul 27 00:28:52 BST 2010

On Mon, Jul 26, 2010 at 8:45 AM, Dave F. <davefox at madasafish.com> wrote:
>  On 26/07/2010 13:35, Nathan Edgars II wrote:
>> On Mon, Jul 26, 2010 at 8:28 AM, Dave F.<davefox at madasafish.com>  wrote:
>>> Layer is used purely as an aid to the renderer to distinguish where two
>>> or
>>> more ways *cross* each other:
>> Not quite purely - it gives nonredundant spatial information when a
>> bridge goes over another. Not that this has anything to do with the
>> layer_change proposal.
> "nonredundant spatial information"
> What's that when it's at home?

Information about the relationship of two physical objects to each
other that isn't otherwise in the data.

In other words, if you have two bridge=yes ways crossing without an
intersection node, that tells you nothing about which one is the
higher bridge. layer=* adds that information.

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