build your own mapquest!
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Build your own MapQuest!. Adding Spatial Smarts to PostgreSQL with PostGIS. Paul Ramsey Refractions Research. - PowerPoint PPT PresentationTRANSCRIPT
Paul Ramsey
Build your own MapQuest!Adding Spatial Smarts to PostgreSQL with PostGIS
Paul RamseyRefractions Research
Paul Ramsey
http://mq-mapgend.websys.aol.com:80/mqmapgend?MQMapGenRequest=FDR2dmwjDE%3byt29%26FDJnci4Jkqj%2cMMCJ%3aHOEvq%3bwy5lab%3a%29uaxlw1w%26%40%24%3a%26%40%24s%26wzx%26a8x%26ESEKGF%3dTPWIK%2crgqabx%26%3d2llarwh%40%24%3a%26%40%24%3a%26a2%3a
Paul Ramsey
On-the-Fly Cartography
GIS DataCartography
EngineColorfulPicture
Paul Ramsey
GIS Data
• File Formats• Data Organization• Coordinate Projections• Data Access• Data Quality
Don’t Panic
Paul Ramsey
File Formats• At least one per vendor
– ESRI : Shape, Coverage, E00, GeoDatabase– CAD : DXF, DGN– Government : SDTS, TIGER, DLG– MapInfo : MIF/MID, TAB– Standards : GML
• Open source conversion– OGR (gdal.maptools.org/ogr)
Paul Ramsey
Data Organization• By Administrative Unit
– Counties, States• By Gridding Unit
– USGS 24K Quads, NTS Mapsheets• By Natural Unit
– Watersheds
Paul Ramsey
Coordinate Projections
1859612,511175-114.068,49.000
GeographicLongitude / Latitude
Albers Equal AreaOrigin -126,0
Parallels 58.5,50.0Offsets 1000000,0
Paul Ramsey
Coordinate Projections• United States
– UTM (Universal Transverse Mercator)– “Stateplane”
• Lambert• Transverse Mercator
– Geographic• Always Find Out the
Projection of Your Data– .prj file
Paul Ramsey
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Data Access• United States
– Mostly Free Federal Data• www.geodata.gov• tiger.census.gov• www.fgdc.gov• transtats.bts.gov• geonames.usgs.gov• www.fws.gov/data
– Some Free State Data– Little Free County / Municipal Data
Paul Ramsey
Data Acce$$• Commercial Providers
– NavTeq– TeleAtlas ( + GDT )– MapInfo– DigitalGlobe– SpaceImaging
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QuickTime™ and aTIFF (Uncompressed) decompressor
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QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Paul Ramsey
Data QualityUSGS DLG TIGER Census
Paul Ramsey
Cartography Engine
ProprietaryArcIMSMapExtreme
Open SourceGeoServerDeeGreeUMN Mapserver
Paul Ramsey
UMN Mapserver• mapserver.gis.umn.edu• Multiple Format Support
– Shape, TAB, Coverage, DGN, PostGIS, More…
• Multiple Projection Support• Standards Support
– OpenGIS Web Map Server– OpenGIS Web Feature Server– OpenGIS Styled Layer Descriptor
Paul Ramsey
UMN MapserverFormat A
Projection 1
Format BProjection 1
Format CProjection 2 “Map File”
ourmap.map
Mapserver
Paul Ramsey
MAP EXTENT 1192130 379840 1199560 385520 SIZE 400 400 SHAPEPATH "/Users/pramsey/Sites" PROJECTION "init=epsg:42102" # BC Albers END LAYER NAME "Lakes" STATUS ON DATA "lakes" TYPE POLYGON PROJECTION "init=epsg:42102" # Geographic END CLASS NAME "Lakes" COLOR 205 223 255 END ENDEND
Paul Ramsey
UMN Mapserver & PostGIS
PostGIS / PostgreSQL
SpatialDatabase
“Map File”ourmap.map
Mapserver
Paul Ramsey
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This is your Database…• “Is there a Main Street?”• “How many patients does the prenatal
center serve?”• “How many buildings in the city have
more than two stories?” • “What is the total amount of cash
withdrawals for customer X?”
Paul Ramsey
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This is your Database on Spatial…
• “What is the total length of Main Street?”
• “What is the total number of patients within 3 miles of the prenatal center?”
• “How many buildings of more than 2 stories are along the parade route?”
• “Have all the cash withdrawals for customer X been within 50 miles of her primary residence?”
Paul Ramsey
PostGIS / PostgreSQL• Extension to PostgreSQL
– src/contrib/• GEOMETRY
– Point, Line, Polygon, Multi*– Functions– Indexes
• http://postgis.refractions.net
Paul Ramsey
PostGIS Types• POINT• LINESTRING• POLYGON• MULTIPOINT• MULTILINESTRING• MULTIPOLYGON• GEOMETRYCOLLECTION
.
..
Paul Ramsey
PostGIS Types
id | geometry | name ------+---------------------------+-------------- 1294 | POINT(1199437.8 382509.2) | Brighton Ave 1295 | POINT(1199369.3 382741.7) | York Pl 1296 | POINT(1199494.8 382751) | Prospect Pl
Paul Ramsey
PostGIS Functions• Single Geometry
– Float : Length(Geometry)– Float : Area(Geometry)– Integer : NumGeometries(Geometry)– Integer : NumPoints(Geometry)– Geometry : Buffer(Geometry,Float)– Point : PointN(Geometry)– Text : AsText(Geometry)– ByteA : AsBinary(Geometry)
Paul Ramsey
PostGIS Functions• Multiple Geometry
– Float : Distance(Geometry,Geometry)– Boolean : Touches(Geometry,Geometry)– Boolean : Intersects(Geometry,Geometry)– Boolean : Disjoint(Geometry,Geometry)– Geometry : Intersection(Geometry,Geometry)– Geometry : GeomUnion(Geometry,Geometry)– Geometry : Difference(Geometry,Geometry)
Paul Ramsey
PostGIS Indexes• Geometries Require Special Index
– Sortable in two dimensions– Cover range of values
• R-Tree Index (GiST Implementation)• Linear Time Picksplit Algorithm• http://postgis.refractions.net/rtree.pdf
Paul Ramsey
Paul Ramsey
Paul Ramsey
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Get on with it!!Get on with it!!
Paul Ramsey
Our Architecture
PostGIS / PostgreSQL
SpatialDatabase
Map Fileourmap.map
Mapserver
GIS Data
Paul Ramsey
Our Steps1. Install / Setup• Mapserver, PostGIS• GDAL, OGR, PROJ4, GD
2. Acquire GIS Data3. Load GIS Data PostGIS4. Write Map File for Mapserver5. …6. Profit!
Paul Ramsey
Acquire Data• For demo, hunted down Oregon data:
1981636 Jul 28 12:02 OR_deci.zip 564501 Jul 28 11:55 county.zip34729355 Jan 9 2003 hydrogm020.tar.gz62246216 Jul 28 11:55 gdt.zip 1853534 Jul 28 11:55 railroads.zip 3293501 Jul 28 12:42 s_12my03.zip
Paul Ramsey
Load Data• Load names data with perl script:
"OR","4H Camp","locale","Coos",41,011,"431355N","1235945W",43.23194,-123.99583,"","",,,216,,"","Dora"
INSERT INTO names VALUES (1,'OR','4H Camp','locale','Coos','SRID=4269;POINT(-123.99583 43.23194)',216,NULL,'Dora’);
Paul Ramsey
Load Shape Files• PostGIS includes Shape loader utility:
shp2pgsql -s 200000 \counties.shp counties | psql demo-oregon
Paul Ramsey
Write Map File• Good computer cartography is the artful
combination of elements, styles, colors and data at appropriate scales.
• MapQuest is an example of excellent cartography.
• So is a National Geographic Atlas of the World.
Paul Ramsey
LAYER TEMPLATE template.html DUMP TRUE NAME "States" METADATA "wms_title" "States" END STATUS ON DATA "the_geom from states" TYPE POLYGON CONNECTIONTYPE POSTGIS CONNECTION "user=pramsey dbname=demo-oregon" PROJECTION "init=epsg:4269" END CLASSITEM "admin_name" CLASS NAME "States" COLOR 255 255 230 OUTLINECOLOR 20 20 20 EXPRESSION "Oregon" END CLASS NAME "States" COLOR 240 240 240 OUTLINECOLOR 20 20 20 END END
Paul Ramsey
Paul Ramsey
Demonstration• iBook G3 800Mhz 128MB
– PostGIS / PostgreSQL, Mapserver, Apache• Roads• States• Counties• Geographical Names• Water Features