pycon2011
DESCRIPTION
TRANSCRIPT
Igor Pochechuev22-23 October, 2011Kyiv, Ukraine
GIS, Python and company
Content
● What is geometry?geometry formats
● How to store geo data?spatial databases
● Where we can get geo data?● Render it!● Demo
General provisionswhat we got
Geometryformats
● WKT, WKB● KML, GML (xml based)● GeoJSON (json based)● Shapefile (ESRI open specification)● etc.
Geometrycommon types
● Point(x, y)
● Line(<point>, <point1>, <point2>, …)
● Polygon(<line>, <line1>, <line2>, …)
MultiGeometryadditional types of geometry
● MultiPoint(<point>, <point1>, <point2>, ...)
● MultiLine(<line>, <line1>, <line2>, ...)
● MultiPolygon(<polygon>, <polygon1>, <polygon2>, ...)
Database layerstoring spatial data
Storing dataspatial databases
● SpatiaLite (SQLite)● MySQL● Oracle● PostGIS (PostgreSQL)
Storing dataright choice
PostGIS
How to get geo data?vector data
Getting datavector data
OpenStreetMap
OpenStreetMapstats
● < 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
OpenStreetMapdownloading ...
● Download planet.osmhttp://wiki.openstreetmap.org/wiki/Planet.osm
● OSM APIhttp://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
Loading data to database
>wget http://wiki.openstreetmap.org/wiki/Planet.osm
OSM2PgSQLloading 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
Rendering ...
Renderingtool choosing
MapServer Mapnik
Mapnikdescription
● Written in C++● Python interface● OpenStreetMap, Flickr, CloudMade use mapnik● PostGIS, Shapefiles, GeoTIFF, OSM XML, ...● PNG, JPG, SVG, PDF, ...
Mapnikmap example
Layersintro
Mapnikcode 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)
Mapnikcode 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)
Mapnikcode 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)
Mapnikcode 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)
Mapnikcode 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')
Mapnikcode 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')
Mapnikcode 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')
Map in browser
Mapniktile description
Mapnikmap services
● Tile Map Service● Web Map Service
MapnikTMS
http: //website.com/<zoom>/<x>/<y>.png
../tiles/12/2451/1360.png
Mapnikusing 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
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>
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>
Tile generating
./generate_tiles.py
Got tiles, what's next?
Frontend mapschoosing tool
● OpenLayers● GeoExt● Leaflet
OpenLayers
● Most powerfull● Most used● Large community● OSM supported● OSM, Google, Yahoo maps in one string● TMS, WMS, WFS● GML, GeoJSON, GeoRSS
OpenLayers
Show time!
Thanks!Questions?