Build your own MapQuest

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Build your own MapQuest!

• Adding Spatial Smarts to PostgreSQL with PostGIS

Paul RamseyRefractions Research
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http//mq-mapgend.websys.aol.com80/mqmapgend?MQMa
pGenRequestFDR2dmwjDE3byt2926FDJnci4Jkqj2cMMCJ
3aHOEvq3bwy5lab3a29uaxlw1w2640243a26402
4s26wzx26a8x26ESEKGF3dTPWIK2crgqabx263d2lla
rwh40243a2640243a26a23a
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On-the-Fly Cartography
ColorfulPicture
Cartography Engine
GIS Data
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GIS Data
Dont Panic

• File Formats
• Data Organization
• Coordinate Projections
• Data Access
• Data Quality

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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)

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Data Organization

• By Administrative Unit
• Counties, States
• By Gridding Unit
• USGS 24K Quads, NTS Mapsheets
• By Natural Unit
• Watersheds

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Coordinate Projections
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Coordinate Projections

• United States
• UTM (Universal Transverse Mercator)
• Stateplane
• Lambert
• Transverse Mercator
• Geographic
• Always Find Out the Projection of Your Data
• .prj file

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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

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Data Acce

• Commercial Providers
• NavTeq
• TeleAtlas ( GDT )
• MapInfo
• DigitalGlobe
• SpaceImaging

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Data Quality
USGS DLG
TIGER Census
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Cartography Engine
Proprietary ArcIMS MapExtreme Open Source GeoS
erver
DeeGree UMN Mapserver
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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

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UMN Mapserver
Format AProjection 1
Mapserver
Format BProjection 1
Format CProjection 2
Map File ourmap.map
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MAP EXTENT 1192130 379840 1199560 385520 SIZ
E 400 400 SHAPEPATH "/Users/pramsey/Sites"
PROJECTION "initepsg42102" BC Albers
END LAYER NAME "Lakes" STATUS ON
DATA "lakes" TYPE POLYGON PROJECTION
"initepsg42102" Geographic
END CLASS NAME "Lakes" COLO
R 205 223 255 END END END
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UMN Mapserver PostGIS
PostGIS / PostgreSQLSpatialDatabase
Mapserver
Map File ourmap.map
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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?
  

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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?

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PostGIS / PostgreSQL

• Extension to PostgreSQL
• src/contrib/
• GEOMETRY
• Point, Line, Polygon, Multi
• Functions
• Indexes
• http//postgis.refractions.net

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PostGIS Types

• POINT
• LINESTRING
• POLYGON
• MULTIPOINT
• MULTILINESTRING
• MULTIPOLYGON
• GEOMETRYCOLLECTION

.
..
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PostGIS Types
id geometry name
----------------------------------------------
- 1294 POINT(1199437.8 382509.2) Brighton Av
e 1295 POINT(1199369.3 382741.7) York Pl 1
296 POINT(1199494.8 382751) Prospect Pl
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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)

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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)

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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

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Get on with it!!
Get on with it!!
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Our Architecture
PostGIS / PostgreSQLSpatialDatabase
Mapserver
Map File ourmap.map
GIS Data
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Our Steps

• Install / Setup
• Mapserver, PostGIS
• GDAL, OGR, PROJ4, GD
• Acquire GIS Data
• Load GIS Data ? PostGIS
• Write Map File for Mapserver
• Profit!

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Acquire Data

• For demo, hunted down Oregon data
• 1981636 Jul 28 1202 OR_deci.zip
• 564501 Jul 28 1155 county.zip
• 34729355 Jan 9 2003 hydrogm020.tar.gz
• 62246216 Jul 28 1155 gdt.zip
• 1853534 Jul 28 1155 railroads.zip
• 3293501 Jul 28 1242 s_12my03.zip

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Load Data

• Load names data with perl script
• "OR","4H Camp","locale","Coos",41,011,"431355N",
  "1235945W",43.23194,-123.99583,"","",,,216,,"","Do
  ra"
  
• INSERT INTO names VALUES (1,'OR','4H
  Camp','locale','Coos', 'SRID4269POINT(-123.9958
  3 43.23194)', 216,NULL,'Dora)
  

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Load Shape Files

• PostGIS includes Shape loader utility
• shp2pgsql -s 200000 \counties.shp counties
  psql demo-oregon

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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.

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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 "userpram
sey dbnamedemo-oregon" PROJECTION "in
itepsg4269" END CLASSITEM "admin_name"
CLASS NAME "States" COLOR 255
255 230 OUTLINECOLOR 20 20 20 EXPRES
SION "Oregon" END CLASS NAME "Sta
tes" COLOR 240 240 240 OUTLINECOLOR
20 20 20 END END
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Demonstration

• iBook G3 800Mhz 128MB
• PostGIS / PostgreSQL, Mapserver, Apache
• Roads
• States
• Counties
• Geographical Names
• Water Features