1. GIS, Python and company
Igor Pochechuev
22-23 October, 2011
Kyiv, Ukraine

3. Content
● What is geometry?
geometry formats
● How to store geo data?
spatial databases
● Where we can get geo data?
● Render it!
● Demo

4. General provisions
what we got

5. Geometry
formats
● WKT, WKB
● KML, GML (xml based)
● GeoJSON (json based)
● Shapefile (ESRI open specification)
● etc.

6. Geometry
common types
● Point
(x, y)
● Line
(<point>, <point1>, <point2>, …)
● Polygon
(<line>, <line1>, <line2>, …)

7. MultiGeometry
additional types of geometry
● MultiPoint
(<point>, <point1>, <point2>, ...)
● MultiLine
(<line>, <line1>, <line2>, ...)
● MultiPolygon
(<polygon>, <polygon1>, <polygon2>, ...)

8. Database layer
storing spatial data

9. Storing data
spatial databases
● SpatiaLite (SQLite)
● MySQL
● Oracle
● PostGIS (PostgreSQL)

10. Storing data
right choice
PostGIS

11. How to get geo data?
vector data

12. Getting data
vector data
OpenStreetMap

13. OpenStreetMap
stats
● < 400 000 registered users
● ~ 1 100 000 000 nodes (points)
● 100 000 000 ways
● ~ 800 — 3 000 nodes added each day
● ~ 100 000 — 300 000 ways added each day
● More statistics:
http://wiki.openstreetmap.org/wiki/Stats

14. OpenStreetMap
downloading ...
● Download planet.osm
http://wiki.openstreetmap.org/wiki/Planet.osm
● OSM API
http://api.openstreetmap.org/api/0.6/map?bbox=11.54,48.14,11.543,48.145
● JOSM (download through desktop app)
http://wiki.openstreetmap.org/wiki/JOSM
● Third part services (GIS LAB)
http://gis-lab.info/projects/osm-export.html

15. Loading data to database

16. >wget http://wiki.openstreetmap.org/wiki/Planet.osm

17. OSM2PgSQL
loading data
● osm2pgsql
-d <db_name>
-H <db_host>
-U <db_user>
-P <db_port>
-c # create tables if needed
-s # store tmp data in database
-S osm.import.style # mapping style
-k # add tags without column to an additional hstore
-z extra_data # hstore column containing all tags that start with 'extra_data'
RU-KRS.osm # path to OSM data file

18. Rendering ...

19. Rendering
tool choosing
MapServer Mapnik

20. Mapnik
description
● Written in C++
● Python interface
● OpenStreetMap, Flickr, CloudMade use mapnik
● PostGIS, Shapefiles, GeoTIFF, OSM XML, ...
● PNG, JPG, SVG, PDF, ...

21. Mapnik
map example

22. Layers
intro

23. Mapnik
code example
import mapnik
m = mapnik.Map(600,300,"+proj=latlong +datum=WGS84")
m.background = mapnik.Color('steelblue')
r = mapnik.Rule()
r.symbols.append(mapnik.PolygonSymbolizer(mapnik.Color('#f2eff9')))
r.symbols.append(mapnik.LineSymbolizer(mapnik.Color('rgb(50%,50%,50%)'),0.1))
s = mapnik.Style()
s.rules.append(r)
m.append_style('World Style',s)

24. Mapnik
code example
import mapnik
m = mapnik.Map(600, 300, "+proj=latlong +datum=WGS84")
m.background = mapnik.Color('steelblue')
r = mapnik.Rule()
r.symbols.append(mapnik.PolygonSymbolizer(mapnik.Color('#f2eff9')))
r.symbols.append(mapnik.LineSymbolizer(mapnik.Color('rgb(50%,50%,50%)'),0.1))
s = mapnik.Style()
s.rules.append(r)
m.append_style('World Style',s)

25. Mapnik
code example
import mapnik
m = mapnik.Map(600, 300, "+proj=latlong +datum=WGS84")
m.background = mapnik.Color('steelblue')
r = mapnik.Rule()
r.symbols.append(mapnik.PolygonSymbolizer(mapnik.Color('#f2eff9')))
r.symbols.append(mapnik.LineSymbolizer(mapnik.Color('rgb(50%,50%,50%)'), 0.1))
s = mapnik.Style()
s.rules.append(r)
m.append_style('World Style',s)

26. Mapnik
code example
import mapnik
m = mapnik.Map(600, 300, "+proj=latlong +datum=WGS84")
m.background = mapnik.Color('steelblue')
r = mapnik.Rule()
r.symbols.append(mapnik.PolygonSymbolizer(mapnik.Color('#f2eff9')))
r.symbols.append(mapnik.LineSymbolizer(mapnik.Color('rgb(50%,50%,50%)'), 0.1))
s = mapnik.Style()
s.rules.append(r)
m.append_style('World Style',s)

27. Mapnik
code example 2
lyr = mapnik.Layer('world', "+proj=latlong +datum=WGS84")
lyr.datasource = mapnik.Shapefile(file='world_borders.shp')
lyr.styles.append('World Style')
m.layers.append(lyr)
m.zoom_to_box(lyr.envelope())
mapnik.render_to_file(m,'world.png', 'png')

28. Mapnik
code example 2
lyr = mapnik.Layer('world', "+proj=latlong +datum=WGS84")
lyr.datasource = mapnik.Shapefile(file='world_borders.shp')
lyr.styles.append('World Style')
m.layers.append(lyr)
m.zoom_to_box(lyr.envelope())
mapnik.render_to_file(m,'world.png', 'png')

29. Mapnik
code example 2
lyr = mapnik.Layer('world', "+proj=latlong +datum=WGS84")
lyr.datasource = mapnik.Shapefile(file='world_borders.shp')
lyr.styles.append('World Style')
m.layers.append(lyr)
m.zoom_to_box(lyr.envelope())
mapnik.render_to_file(m,'world.png', 'png')

30. Map in browser

31. Mapnik
tile description

32. Mapnik
map services
● Tile Map Service
● Web Map Service

33. Mapnik
TMS
http: //website.com/<zoom>/<x>/<y>.png
../tiles/12/2451/1360.png

34. Mapnik
using osm scripts
● svn export http://svn.openstreetmap.org/applications/rendering/...
● ./generate_xml.py --password 'value' --host 'value' --port 'value'
--user 'value' --dbname 'value'
● MAPNIK_MAP_FILE='osm.xml' MAPNIK_TILE_DIR='tiles/'
./generate_tiles.py

35. Mapnik XML
<Map bgcolor="#b5d0d0">
<Style name="map_style">
<Rule>
<MaxScaleDenominator>[scale]</MaxScaleDenominator>
<MinScaleDenominator>[scale]</MinScaleDenominator>
<Filter>[field]='value'</Filter>
<PointSymbolizer/>
<LineSymbolizer/>
<PolygonSymbolizer/>
…
</Rule>
</Style>

36. Mapnik XML
<Layer name="misc_boundaries">
<StyleName>map_style</StyleName>
<Datasource>
<Parameter name="table">
(select way,way_area,name,boundary from polygon
where boundary='national_park') as boundary
</Parameter>
<Parameter name='dbname'>[dbname]</Parameter>
<Parameter name='host'>[host]</Parameter>
<Parameter name='user'>[user]</Parameter>
…
</Datasource>
</Layer>

37. Tile generating
./generate_tiles.py

38. Got tiles, what's next?

39. Frontend maps
choosing tool
● OpenLayers
● GeoExt
● Leaflet

40. OpenLayers
● Most powerfull
● Most used
● Large community
● OSM supported
● OSM, Google, Yahoo maps in one string
● TMS, WMS, WFS
● GML, GeoJSON, GeoRSS

41. OpenLayers

42. Show time!

43. Thanks!
Questions?