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5/4/16 18Postgis Topology will replace Postgis SimpleFeature
Closed LineString where it is data
5/4/16 19Postgis Topology will replace Postgis SimpleFeature
Closed linestring where no data
On this layer : Postgis Topology → 5 points
: Postgis Simple Feature → 333105 (333100 duplicates) points
5/4/16 20Postgis Topology will replace Postgis SimpleFeature
Create s map with full coverage
Use Postgis Topology for line layers ?Intersecting nodes
Shared lines
5/4/16 22Postgis Topology will replace Postgis SimpleFeature
Change an exiting LineString, snap to crossing line
5/4/16 23Postgis Topology will replace Postgis SimpleFeature
Draw a LineString, no snap to
What about point layers and Postgis Topology ?
TopoJSON
5/4/16 25Postgis Topology will replace Postgis SimpleFeature
Postgis Topology and points
5/4/16 26Postgis Topology will replace Postgis SimpleFeature
So what is the end users reaction to just draw new lines ?
:-)Easy, faster, history kept, rollback changes
5/4/16 27Postgis Topology will replace Postgis SimpleFeature
Developer perspective using SimpleFeature
Weaknesses withSimpleFeature
● Duplication of lines
● Total replacement
● Mix of new and old points
● Bandwidth usage
5/4/16 28Postgis Topology will replace Postgis SimpleFeature
Development perspective move border when SimpleFeature
Simple Features and drifting points
5/4/16 30Postgis Topology will replace Postgis SimpleFeature
Drifting points
5/4/16 31Postgis Topology will replace Postgis SimpleFeature
Drifting points
14 Km off
Simple Features “equal”
DE-9IM : T*F**FFF*OR
II � ~IE � ~BE � ~EI � ~EB
SimpleFeature is not using the relationalfeatures of Postgres.
Postgis Topology is using the relationalfeatures of Postgres.
Development perspective And
Postgis Topology
5/4/16 35Postgis Topology will replace Postgis SimpleFeature
Develop
perspective
using
Postgis
Topology
Slide from: http://strk.keybit.net/projects/postgis/Paris2011_TopologyWithPostGIS_2_0.pdf
5/4/16 36Postgis Topology will replace Postgis SimpleFeature
ApacheTomcat
Java app
pgtopo_update_sqlPostgis Topology
GeoJSON
TopoJSON
GeoJSON
TopoJSON/Ids
System overview for the update client
5/4/16 37Postgis Topology will replace Postgis SimpleFeature
Development GitLab, GitHub, Continues Integration
deploy_war_utv: stage: deploy script: - mvn package tomcat7:redeploy -Pkartupd01utv only: - develop deploy_war_test: stage: deploy script: - mvn package tomcat7:redeploy -Pkartupd01test only: - test
Running inside Postgres
5/4/16 38Postgis Topology will replace Postgis SimpleFeature
pgtopo_update_sql
Postgis Topology
● pgtopo_update_sql
uses
Postgis Topology
to check and
adjust result
https://github.com/NibioOpenSource/pgtopo_update_sql
“developed with very good help from Sandro Santilli”
● Postgis Topology package handles the postgis operations
5/4/16 39Postgis Topology will replace Postgis SimpleFeature
pgtopo_update_sql● Called from Java by using stored proc
Postgis Topology
5/4/16 40Postgis Topology will replace Postgis SimpleFeature
pgtopo_update_sql Partly developed as a part of a map update project
● Focus have been this projects used cases ● Needs redesign, but it works for this project ● The update method need a redesign● Have lot of tests that help us
5/4/16 41Postgis Topology will replace Postgis SimpleFeature
Development perspective move border with Postgis Topology
Only new linesfrom client
to
Server
Postgis Topology means
- no drifting points- easier to undo
fkey1 = fkey2Postgis Topology benefits
both end user and developer when workingon surface and line layers.
Postgis Topology
- tested with one billion pointshttp://www.slideshare.net/laopsahl/foss4-g-topologyjuly162015
- seems to be solid and few errors
5/4/16 45Postgis Topology will replace Postgis SimpleFeature
{"type":"Topology","objects":{"collection":{"type":"GeometryCollection","geometries":[{"type":"Polygon","properties":{"id":520},"arcs":[[-1]]}]}},"arcs":[[[9717,419],[-1126,-419],[-5070,958],[-2113,898],[-1126,2036],[422,2335],[-704,2754],[1972,1018],[2253,0],[1267,-419],[1409,-1437],[3098,-6467],[-282,-1257]]],"transform":{"scale":[0.007100710071007101,0.016701670167016704],"translate":[1088433,7800262]}}
● GeoJSON 7.6 MB
● TopoJSON 1.3 MB
● 80 % reduction
What is TopoJSON ?
5/4/16 46Postgis Topology will replace Postgis SimpleFeature
Reduced client network bandwidth
known and fixed bandwidth
5/4/16 47Postgis Topology will replace Postgis SimpleFeature
ST_Simplify perfect works best Postgis Topology
7990316 bytes 149400 byte (98 % less)
5/4/16 48Postgis Topology will replace Postgis SimpleFeature
ST_Simplify gives you a good overview with less points
7990316 bytes 149400 byte (98 % less)
5/4/16 49Postgis Topology will replace Postgis SimpleFeature
ST_Simplify and Simple Feature Using Topology
common border will not match. No problem
5/4/16 50Postgis Topology will replace Postgis SimpleFeature
ST_Simplify and line layers with Topolgy
GeoServer , MapServer and Postgis Topology
5/4/16 52Postgis Topology will replace Postgis SimpleFeature
So what is the end developer reaction Using Postgis Topology ?:-)
Postgis Topology fits new data in to current map.(no id problem, no data lost, no duplication,less data,
faster development time)
IF “YOU NEED SIMPLE USER INTERFACE FOR MAPS UPDATE” AND“MAPS OF HIGH QUALITY”
THENUSE POSTGIS TOPOLOGY
ELSEUSE WHATEVER YOU LIKE
END IF;
Hopefully at next FOSS4G Postgis Topology will be a main themewith workshops many talks.
Thanks for your attention [email protected]
