OSM Nanjing: Year of Edits

mapnik-nanjing-edits.xml

<Map background-color="#232323" minimum-version="0.7.2" srs="+proj=latlong +datum=WGS84">
  <Style name="style-by-timestamp">

    <Rule>
      <Filter>[timestamp] = '2012'</Filter>
      <LineSymbolizer stroke="#95a7ed" stroke-width="1" /></Rule>
    <Rule>
      <ElseFilter />
      <LineSymbolizer stroke="#9090A0" stroke-width="1" /></Rule>
  </Style>
  <Layer name="all" srs="+proj=latlong +datum=WGS84" status="on">
    <StyleName>style-by-timestamp</StyleName>
    <Datasource>
      <Parameter name="type">osm</Parameter>
      <Parameter name="file">map-nanjing-t.osm</Parameter>
    </Datasource>
  </Layer>
</Map>

mkmap.py

#!/usr/bin/env python2

from mapnik import *

mapfile = 'mapnik-nanjing-edits.xml'
map_output = 'map-nanjing-edits.png'

m = Map(480, 480)
load_map(m, mapfile)
bbox=(Envelope(118.595,31.872,118.982,32.26))

m.zoom_to_box(bbox)
print "Scale = " , m.scale()
render_to_file(m, map_output)

osm-transform.py

#!/usr/bin/env python2
# -*- coding: utf-8 -*-

from xml.dom.minidom import parse
import codecs

dom1 = parse('map-nanjing.osm')

ways = dom1.getElementsByTagName('way')

for w in ways:
    t = w.getAttribute('timestamp')[:4]
    nt = dom1.createElement('tag')
    nt.setAttribute('k','timestamp')
    nt.setAttribute('v',t)
    w.appendChild(nt)

with codecs.open('map-nanjing-t.osm','w', 'utf-8') as out:
    dom1.writexml(out)