[OSM-talk] Another point in support of ways as ordered lists

[Robert Hart]

Yes, I don't have a problem with the names. Anyway, it was just a
suggestion. The problem I have is finding the location. For a node the
location is attributes of the node, but for a way, you have to dereference
the segments then nodes, and find a mid point.

My current code just does ways (see below), but I'd like to include nodes as
way:

  <xsl:template name='keyDraw'>
    <xsl:for-each select="$data/osm/way/tag[@k='name']">
      <xsl:sort select="@v"/>
	<xsl:variable name="col" select="floor(position() div (($height -
40) div 6))" />
	<xsl:variable name="row" select="position() - $col * floor(($height
- 40) div 6)" />
        <text font-family='Verdana' font-size='6px' fill='black'>
          <xsl:attribute name='x'><xsl:value-of select='10 + $width +
$col*80'/></xsl:attribute>
          <xsl:attribute name='y'><xsl:value-of select='20 + 6 *
$row'/></xsl:attribute>
          <xsl:value-of select="@v"/>
        </text>
        <text font-family='Verdana' font-size='6px' fill='black'>
          <xsl:attribute name='x'><xsl:value-of select='80 + $width +
$col*80'/></xsl:attribute>
          <xsl:attribute name='y'><xsl:value-of select='20 + 6 *
$row'/></xsl:attribute>
	  <xsl:variable name='startseg' select='../seg[1]' />
	  <xsl:variable name='endseg' select='../seg[position()=last()]' />
	  <xsl:variable name='start'
select='key("segmentById",$startseg/@id)' />
	  <xsl:variable name='end' select='key("segmentById",$endseg/@id)'
/>
	  <xsl:variable name='startNode'
select='key("nodeById",$start/@from)'/>
	  <xsl:variable name='endNode' select='key("nodeById",$end/@from)'/>
	  <xsl:variable name='lat' select='($startNode/@lat + $endNode/@lat)
div 2' /> 
	  <xsl:variable name='lon' select='($startNode/@lon + $endNode/@lon)
div 2' /> 
          <xsl:value-of select="floor(($lon - $bllon) div 0.0089928)"/>
          <xsl:value-of
select="substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ',floor((($lat - $bllat) div
0.0089928) * $projection),1)"/>
	  <!--<xsl:value-of select="$start" />,
	  <xsl:value-of select="$lat" />,
	  <xsl:value-of select="$lon" />-->
        </text>
     </xsl:for-each>
  </xsl:template>
 

-----Original Message-----
From: Etienne
To: Robert Hart
Cc: Nick Whitelegg; talk-bounces at openstreetmap.org ; talk at openstreetmap.org 
Sent: 9/26/2006 9:29 PM
Subject: Re: [OSM-talk] Another point in support of ways as ordered lists

Rob
An xpath expression like $elements[tag[@k="name"]] will select all nodes
and ways with a name tag.  You don't need to do anything special to
combine nodes and ways, because the $elements variable is already a set
of nodes and ways that match the rule (assuming the rule is <rule
e="node|way">). 

If you want all the names in alphabetical order try something like:
<xsl:for-each select='$elements[[tag[@k="name"]]/@name''>
  <xsl:sort order="ascending">
  ...

Etienne 



On 9/26/06, Robert Hart < Robert.Hart at burohappold.com
<mailto:Robert.Hart at burohappold.com> > wrote:

I just had a brain wave. If ways are ordered lists of nodes, then POIs
can
be ways containing only one node. This may sound odd, but I think it has
real advantages (well at least one advantage anyway...)

I've been playing around with creating map indices in osmarender. To do
this 
I need to know the name and approximate location of everything that
should
be included in the index. This means I have to handle nodes and
ways/areas
seperately, which is going to be painful if I want the whole index in 
alphabetical order (as opposed to having separate indices for ways and
nodes). If POIs were single-node ways, everything would just work with
one
code path.

Rob



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