121114_fossgis_tourpl.pdf

Route Planning with FOSS:OpenStreetMap, PostGIS, OSRM and

OpenLayers

Michael Rüegg

Institute For SoftwareUniversity of Applied Sciences Rapperswil

/ch/open Workshop, ZürichNovember, 2012

Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap

4 Open Source Routing Machine

5 OpenLayers

6 Showcase: Tourpl

Michael Rüegg (IFS) Route Planning with FOSS November, 2012 2 / 40

Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


What is GIS?

GIS stands for Geographic Information SystemUsed to answer what is where on the Earth’s surfaceGIS data is typically stored in a Spatial DatabaseA spatial database

defines special data types for geometric objects (e. g.,polygons)allows to save geometric data in regular (relational)databasesprovides special functions and indexes for querying andmanupulating spatial data


Map projections & spatial reference systems

Basic problem: How to get from a round world to a flat map?⇒ Map projections: portray Earth’s curved to a flat surface

Spatial Reference System (SRS)European Petrolueum Survey Group Geodesy (EPSG)Geodesy is the study of the shape of the EarthWGS84: The World Geodetic System is a standard for usein cartography, geodesy and navigationCHLV03: The coordinate system for Switzerland


Layer conceptGIS is closely associated with the layer conceptA GIS allows to work in various levels and their properrepresentations⇒ Goal: Combination of data to get new information

Figure: http://www.digital-geography.com/concept-of-layers-in-a-gis


http://www.digital-geography.com/concept-of-layers-in-a-gis

GIS file formats

Standards for encoding geographical information into a fileRaster vs. vector formatsCommon vector formats:

Drawing Interchange Format (DXF): CAD data file formatdeveloped by AutodeskESRI Shapefile: popular geospatial vector data format fromEnvironmental Systems Research Institute (ESRI)Keyhole Markup Language (KML): XML dialect forexpressing geographic visualization within two-dimensionalmaps and three-dimensional Earth browsersSpatialite: free GIS that enables spatial queries and objectsfor SQLite


Geometric data typesA feature represents the basic data unit in a GISHow can we store and represent geographic features in adatabase?⇒ Simple Feature for SQL (SFS) ModelStorage model for geographical data using well-known text(WKT)Basic geometric data types: points, linestrings, polygons

Figure: Source Wikipedia


Overview SFS data types



Well-known text (WKT)

Text markup language for representing vector geometryobjects on a mapExamples (Source Wikipedia):

Type WKT Figure

Point POINT (30 10)

LineString LINESTRING (30 10, 10 30, 40 40)

Polygon POLYGON ((30 10, 10 20, 20 40,40 40, 30 10))

Polygonwith hole

POLYGON((35 10, 10 20, 15 40, 45 45, 35 10),

(20 30, 35 35, 30 20, 20 30))


Spatial RelationshipsAn important goal when using a GIS is determining thespatial relationships between geometric objects



Spatial Indices

A spatial index is used to optimize spatial queriesSpatial order structure: What is spatially close togethershould also be close in memory

Figure: R-Tree example


Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


What is PostGIS?

Extension of PostgreSQL, “spatially enables” thePostgreSQL serverImplements the SFS modelOpen Source (GNU General Public License)Data loaders (e. g., ESRI shape files)>330 geometric functions: distance, area, union,intersection, etc.

Latest release is 2.0.1 (June 2012)


How to create PostGIS enabled databases

Create PostGIS database template:$ createdb template_postgis$ psql template_postgis -c"create extension postgis"

$ psql template_postgis -f<installdir>/postgresql/share/contrib/postgis-2.0/legacy.sql

Now we can create a DB from our template:$ createdb -T template_postgis gis_db

To verify the installed PostGIS version, use this:$ psql gis_db -c "SELECT PostGIS_Full_Version()"


PostGIS Metadata tables

There are two OpenGIS meta-data tablesSPATIAL_REF_SYS has >3’000 spatial reference systems:CREATE TABLE spatial_ref_sys (srid INTEGER NOT NULL PRIMARY KEY,auth_name VARCHAR(256),auth_srid INTEGER,srtext VARCHAR(2048),proj4text VARCHAR(2048));

GEOMETRY_COLUMNS contains the spatial columns:CREATE TABLE geometry_columns (f_geometry_column VARCHAR(256) NOT NULL,coord_dimension INTEGER NOT NULL,srid INTEGER NOT NULL,type VARCHAR(30) NOT NULL);


Creating basic geometries with PostGIS

We create a basic point object (x,y):SELECT ST_Point(1, 3) AS ExamplePoint;

No spatial reference system used (default is Cartesiangrid). Let’s use WGS84:SELECT ST_SetSRID(ST_Point(8.515342,47.389058), 4326);

The same can be done by using WKT:SELECT ST_GeomFromText(’POINT(8.515342,47.389058)’, 4326);

The same for LineStrings and Polygons:SELECT ST_GeomFromText(’LINESTRING(1 1,2 2,3 3)’)AS MyLine;

SELECT ST_GeomFromText(’POLYGON((0 1,1 -1,-1 -1,0 1))’)As MyTriangle;


Creating a spatial table

1 Create a “normal” non-spatial table:CREATE TABLE beers (id NOT NULL PRIMARY KEY,name VARCHAR,price FLOAT4);

2 Add a spatial column:SELECT AddGeometryColumn(’public’, ’beers’,

’geom’, 4326,’POINT’, 2);

Syntax of AddGeometryColumn:AddGeometryColumn(<schema_name>, <table_name>,

<column_name>, <srid>,<type>, <dimension>)


Creating a spatial index

Create a spatial index:CREATE INDEX in_beers ON beers USING gist(geom);

New dataset for PostGIS functions:INSERT INTO beers(name, price, geom) VALUES (’Manor’, 1.15,GeometryFromText(’POINT(8.81915 47.22640)’,4326));

SELECT * from beers order by price;21;"Coop Sunnehof"; 1.05;"01010000..."18;"Manor"; 1.15;"01010000..."20;"Dorflade"; 2.4; "01010000..."23;"Rappi Bier Factory";2.9; "01010000..."22;"Lido Markt"; 3.1; "01010000..."19;"Biergarten"; 3.5; "01010000..."17;"Nelson Pub"; 4.5; "01010000..."


PostGIS FunctionsSELECT name, price, round(st_distance_sphere(geom,

GeometryFromText(’POINT(8.816511 47.223064)’, 4326))::numeric, 0)

AS "distance" FROM beersORDER BY distance;

"Biergarten"; 3.5; 235"Dorflade"; 2.4; 300"Nelson Pub"; 4.5; 381"Manor"; 1.15;422"Coop Sunnehof";1.05;706

Note that we must convert the point to EPSG 4326!ST_Distance_Sphere: Returns minimum distance inmeters between two lon/lat geometriesfloat ST_Distance_Sphere(geometry lonlatA,geometry lonlatB)


Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


OpenStreetMap Data

OpenStreetMap (OSM) export format is a XML formatTopological data structure with four data types:

Nodes are points with a geographic position, stored asWGS84 coordinates (e. g. POIs)Ways are ordered node lists representing a polyline(e. g. streets, rivers, parks)Tags are used to store metadata about the map objectsRelations are used for representing the relationship ofexisting nodes and ways (e. g. turn restrictions on roads)

OpenStreetMap data: www.geofabrik.deOSM data for Switzerland in PBF Format (ProtocolbufferBinary Format): download.geofabrik.de/osm/europe/switzerland.osm.pbf


www.geofabrik.de

download.geofabrik.de/osm/europe/switzerland.osm.pbf

download.geofabrik.de/osm/europe/switzerland.osm.pbf

Load OSM data into PostgreSQL

osm2pgsql is a utility that converts OSM data toPostgreSQL databasesosm2pgsql is a lossy conversion utilityTwo main modes of running: normal and slim modeNormal mode uses memory for intermedia storageSlim mode uses 3 on-disk tracking tables:planet_osm_nodes, planet_osm_ways,planet_osm_rels


Load OSM data into PostgreSQL

$ osm2pgsql --create --slim --extra-attributes \--database <DB_NAME> --prefix osm --style \/usr/local/share/osm2pgsql/xyz.style \--username <DB_USER> --port <DB_PORT> \--hstore-all --input-reader pbf \--extra-attributes switzerland.osm.pbf

-hstore: Generate a hstore (key/value) columnBy using hstore we can use any tag in SQL queries:gis_db=> SELECT COUNT(*) FROM planet_osm_pointWHERE ((tags->’man_made’) = ’tower’);

osm2pgsql overwrites the tables and create them fresh bydefault (use -append instead if necessary)


Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


Introduction

High performance routing machineDoes not use an A* variant to compute shortest path, butContraction Hierarchies (CH)Written in C++, available under the GNU license


Installation

For Ubuntu 12.04:$ sudo apt-get install build-essential git scons \pkg-config libprotoc-dev libprotobuf7 \protobuf-compiler libprotobuf-dev libosmpbf-dev \libpng-dev libbz2-dev libstxxl-dev libstxxl-doc \libstxxl1 libxml2-dev libzip-dev \libboost-thread-dev libboost-system-dev \libboost-regex-dev libboost-filesystem-dev \lua5.1 liblua5.1-0-dev libluabind-dev

$ git clone https://github.com/DennisOSRM/Project-OSRM.git$ scons -j4

More information: https://github.com/DennisOSRM/Project-OSRM/wiki/Building%20OSRM


https://github.com/DennisOSRM/Project-OSRM/wiki/Building%20OSRM

https://github.com/DennisOSRM/Project-OSRM/wiki/Building%20OSRM

Configurationserver.ini

server.ini contains properties for the routing engine:Threads = 8IP = 0.0.0.0Port = 5000

hsgrData=switzerland.osrm.hsgrnodesData=switzerland.osrm.nodesedgesData=switzerland.osrm.edgesramIndex=switzerland.osrm.ramIndexfileIndex=switzerland.osrm.fileIndexnamesData=switzerland.osrm.names


ConfigurationRouting profiles

Routing profiles are specified in Lua filesExample car.lua:peed_profile = {["motorway"] = 90,["motorway_link"] = 75,["trunk"] = 85,["trunk_link"] = 70,["primary"] = 65,["primary_link"] = 60,["secondary"] = 55,["tertiary"] = 40,["residential"] = 25,["living_street"] = 10,["service"] = 15,["ferry"] = 5,["default"] = 50

}Michael Rüegg (IFS) Route Planning with FOSS November, 2012 29 / 40

Running OSRMExtracting the Road Network 1/2

OSM data contains information irrelevant to routingOSM data needs to be normalized before being processedThis is done by the OSRM tool named extractorParses the content of the OSM file and writes:

A .osrm file containing the routing dataA .osrm.restrictions file containing the restrictions tomake certain turns during navigationA .osrm.names file which contains the road names

Let’s execute it:$ ./osrm-extract switzerland.pbf


Running OSRMExtracting the Road Network 2/2

The extractor is able to handle bzip2 compressed files aswell as PBF filesExternal memory accesses are handles by the stxxl librarystxxl must be configured in a file .stxxl

File format:disk=full_disk_filename,capacity,access_method

Example: disk=/tmp/stxxl,25000,syscall


Running OSRMCreating the hierachy and run OSRM

To create hierarchy (the precomputed data that enablesOSRM to find the shortest path extermly fast), type:$ ./osrm-prepare switzerland.osrm \switzerland.osrm.restrictions

Nearest-neighbor data structure and node map are createdAfterwards, 4 files should exist:

map.osrm.hsgr (the hierarchy)map.osrm.nodes (the nodemap)map.osrm.ramIndex (stage 1 index)map.osrm.fileIndex (stage 2 index)

To run the engine, just type:./osrm-routed


OSRM Serviceslocate: Location of nearest node to a given coordinatenearest: Location of nearest point on any street segment fora given coordinateviaroute: Computation of shortest path between twocoordinates given an ordered list of via pointsQuery format:http://server:5000/_service_?param1=value&...&paramX=value

Example (from here to Zürich Mainstation):$ curl "server:5000/viaroute?loc=47.389058,\> 8.515342&loc=47.378188,8.539204" | python -mjson.tool

{ "version": 0.3,"status":0,"status_message":"Found route between points","route_geometry":["4","Duttweilerstrasse",239,4,17,"239m","NE",38],["2","Foerrlibuckstrasse",363,7,27,"363m","E",84],"route_summary":{"total_distance":3220,"total_time":237,...


Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


IntroductionOpenLayers is a JavaScript library for displaying map datain web browsers (no server-side dependencies)Most popular open source software web-mapping clientAbility to overlay proprietary non-OGC-compliant mappinglayers with OGC WMS, WFS and WFS-T layersVarious controls to build custom toolbars, menus andwidgets for editing the map


Example

<script src="OpenLayers.js"></script><script type="text/javascript">var map;function init() {

map = new OpenLayers.Map(’map’, { controls: [new OpenLayers.Control.Navigation(),new OpenLayers.Control.PanZoomBar(),new OpenLayers.Control.LayerSwitcher({’ascending’:false}),new OpenLayers.Control.Permalink(),new OpenLayers.Control.ScaleLine(),new OpenLayers.Control.Permalink(’permalink’),new OpenLayers.Control.MousePosition(),new OpenLayers.Control.OverviewMap(),new OpenLayers.Control.KeyboardDefaults()],numZoomLevels: 6

});map.addLayer(new OpenLayers.Layer.Google("Google Hybrid", {

type : google.maps.MapTypeId.HYBRID,numZoomLevels : 20

}));var position = new OpenLayers.LonLat(lon, lat).transform(fromProjection, toProjection);var markers = new OpenLayers.Layer.Markers("Markers");map.addLayer(markers);markers.addMarker(new OpenLayers.Marker(position));

}</script>


Outline

1 GIS 101

2 PostGIS

3 OpenStreetMap


5 OpenLayers

6 Showcase: Tourpl


Tourpl

Tourpl — “Der Tourenplaner”A route planning web application developed at University ofApplied Sciences RapperswilTravelling Salesman Problem (TSP)Uses PostGIS, OSM data, osm2pgsql, OSRM andOpenLayersAvailable at www.tourpl.ch⇒ Demonstration


www.tourpl.ch

Thanks for your attention!

INSTITUTE FORSOFTWAREIFS


Bibliography I

Regina O. Obe and Leo S. HsuPostGIS in Action.Manning, 2011

Stefan KellerUnterrichtsmaterialien “Geodatenbanksysteme”.University of Applied Sciences Rapperswil, 2012

Dennis LuxenOSRM Wiki.https://github.com/DennisOSRM/Project-OSRM/wiki


https://github.com/DennisOSRM/Project-OSRM/wiki

https://github.com/DennisOSRM/Project-OSRM/wiki

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