brujug presentation 2011-12-15

7/31/2019 Brujug Presentation 2011-12-15

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Spatial Data in the

Enterprise

Thursday 5 January 12


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Used to be a GIS-expert/consultant

Works as software architect for Enterprise Systems(Vlaamse Overheid)

Works on the intersection of JEE and spatial datatechnology

Committer for Hibernate Spatial, Geolatte



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Spatial data for Java programmers

Persisting spatial data with Hibernate Spatial

Spatial data processing with Geolatte (+ tutorial)



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Locations are defined w.r.t. a spatial reference system

geographic terms or identifiers (names, addresses, postalcodes)

coordinates of a coordinate reference system



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Geographic coordinatesLatitude = angle w.r.t.equatorial plan

Longitude = angle w.r.t. prime

meridian

Ellipsoid approximates Geoid

Geoid is equipotential surfaceat mean sealevel

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Geodetic Datum

Fixes ellipsoid to geoid

WGS84World geodetic datum

Used for GPS

Wrong datum =>

Errors of 50 - 500m. !!

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Projected coordinate system

Chose so as to preserves some aspectsEqual-AreaEqui-DistantConformal

Valid locally

Examples

Lambert 72

LAEA 3035

UTM

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Coordinate Reference Systems in practice

Identified by EPSG identifier or SRID

See: http://spatialreference.org/ or http://www.epsg-registry.org/

Gotchas:

Calculating with geographic coordinates

Lat/Long or Long/Lat ?

Google Maps -- EPSG:90093

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http://www.epsg-registry.org/http://www.epsg-registry.org/http://www.epsg-registry.org/http://www.epsg-registry.org/http://www.epsg-registry.org/http://spatialreference.org/http://spatialreference.org/


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Rectangular grid(usually)

One data value per cell

Related to graphics

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Geometry = coordinate geometry + a coordinatereference system

Coordinate geometry = Lists (of lists) of coordinates

describing the boundaries of the geometry

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Named topological relationships

Disjoint

Intersects

Touches

CrossesOverlaps

Within

Contains

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GIS for spatial analysis systems for research ordecision-support

e.g. ESRI Arc/Info (later ArcGIS)

No standardisation, limited interoperabilitye.g. Understanding GIS the Arc/Info way

Exotic: i.e. non-native to common IT-ecosystems



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Emergence of open standards

Free/Open source software

FOSS4G

2005: Google Maps showed the future

Abundant spatial data

GPS, OpenStreetMap



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Standard-compliant service componentse.g. Web Mapping Service (ESRI, Geoserver, Deegree, Autodesk)

Spatial data capability in commodity software

Postgresql (postgis), Hibernate Spatial, JTS/Geotools/Geolatte

Cheap desktop mapping

e.g. Quantum GIS, uDIG, MapInfo

Professional GIS on the desktop

e.g. ESRI ArcGIS, GRASS (F/OSS)



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[A]ims to establish a structured set of standards for information concerningobjects or phenomena that are directly or indirectly associated with a locatiorelative to the Earth.

ISO 19100 series standards

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http://www.isotc211.org/http://www.isotc211.org/http://www.isotc211.org/


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The Open Geospatial Consortium (OGC) is an international industryconsortium of 440 companies, government agencies and universitiesparticipating in a consensus process to develop publicly available interfacstandards. OGC Standards support interoperable solutions that "geo-enable" the Web, wireless and location-based services and mainstream ITThe standards empower technology developers to make complex spatial

information and services accessible and useful with all kinds of applications

Collaborates closely with TC211

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http://www.opengeospatial.org/http://www.opengeospatial.org/http://www.opengeospatial.org/http://www.opengeospatial.org/standards/http://www.opengeospatial.org/standards/


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ISO 19107 - Spatial schema

Geometries in 3-dimensional space

A.k.a OGC Topic 1: Feature Geometry (ISO 19107 SpatialSchema)

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OGC Simple Features Specification for SQL (SFS)

Geometry by linear interpolation between (2D-)coordinates

Widely supported in databases, libraries

ISO 19125 Simple features access (SFA)Successor to SFS

A.k.a OGC Simple Feature Access

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Geometry methods:

Basicdimension(), SRID(), envelope(), geometryType(), ...

Querydisjoint(), within(), overlaps(), relate(), ...

Analysisdistance(), bufer(), union(), ...



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Coordinates in 2-, 3- or 4 dimensions

X-, Y-coordinates for location in 2D

Z-coordinate, typically for elevation

M-coordinate for measures (SFA only)

Not real 3D, but 2.5D

Spatial operations work in the "map geometry" of the data and will therefornot reflect z or m values in calculations (e.g., Equals, Length) or in generatioof new geometry values (e.g., Bufer, ConvexHull, Intersection).



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(x1,y1,m=0)

(x2,y2,m=1.3)

(x3,y3,m=2.5)

(x4,y4,m=3.2)

(x5,y5,m=4.1)

(x2,y2,m=2.1)



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ISO 13249-3: SQL/MM - Part 3: Spatial Data

Originally based on the OGC Simple Features Specification forSQL, v1.1 (SFS)

Defines non-simple geometries: ST_CircularString

All types and methods prefixed with ST_

Also defines advanced structures: Topologies, Network

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ava interfaces for ISO 19100 series specifications

Proposed OGC standard

Very literal translation: complicated, verbose

Not widely used

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http://www.geoapi.org/http://www.geoapi.org/


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WKT: Well-known Text Representations for Geometry

POINT(0 1), LineString ( 10 10, 20 20, 30 40),Polygon ((10 10, 10 20, 20 20, 20 15, 10 10))

WKB: Well-known Binary Representations for Geometry

! WKT/WKB do not contain SRID, Z- or M-coordinates !

Several Extended variants

Postgis EWKT/EWKB, Sql Server



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Geographic Markup Language (GML)

ISO 19136 == OGC GML (currently v3.2.1)

Large, complex specification==> implementations are often incomplete, inconsistent

SFGML: Simple Features profile, a sane subsetMore information: http://www.ogcnetwork.net/gml

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http://www.ogcnetwork.net/gmlhttp://www.ogcnetwork.net/gml


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ESRI Shapefile format

Open industry standard

Same scope as SFA/SFS

Widely used, supported by most systems

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WMS: Web Map Service (OGC)

Dynamic mapping

TMS: Tile Map Serve (informal)

Static tile maps

WFS: Web Feature Service (OGC)

Serves vector data

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Postgresql / Postgis

Postgis extension

Originally based on Simple features Spec.

Increasingly compliant with SQL/MM

Very good implementation, well-documented

MySQL

Partially compliant with SFS

Spatial relations based on bounding box ! (incorrect)

Read the documentation!!

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Oracle 10g

SDOGEOMETRY type: proprietary, non-standard model

Undocumented OGC compliance functions!

Oracle 11gAdds ST_GEOMETRY type

SQL/MM compliantInteroperable with SDOGEOMTRY

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Microsoft SQL Servers

Excellent SFS-compliant implementation

Storage format publicly documented

IBM InformixExcellent SFS-compliant implementation

Storage format not publicly documented

GeoDB (H2 based)

https://github.com/jdeolive/geodb/wiki

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https://github.com/jdeolive/geodb/wikihttps://github.com/jdeolive/geodb/wiki


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The problem

SFS was intended for planar 2D geometries (projected mapcoordinates)

What about geodetic data such as WGS84?

Geography

Like a geometry, but assumes geodetic coordinates

ST_Length(), ST_Area(), ST_Distance() return meters

Available in Postgis (WGS84 only) and SQL Server

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ava Topology Suite

Implements Simple Features Specification for SQLLimited to 2D (but can store Z-coordinates)Problematic with geodetic data (long/lat)

Many computational geometry algorithms

Good quality, simple to use, very stableGEOS: port to C, used in Postgis

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http://tsusiatsoftware.net/http://tsusiatsoftware.net/http://tsusiatsoftware.net/http://tsusiatsoftware.net/


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GeoTools

Framework for creating GIS-applicationsReferencing, Rendering, Data access, ...

Fully interoperable with JTS & versions of GeoAPI

Large (sprawling) set of libraries

Code of variable quality

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http://www.geotools.org/http://www.geotools.org/http://www.geotools.org/http://www.geotools.org/


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Geotoolkit.org (Geotk)

GeoTools fork

Implements parts of GeoAPI

Started as clean up and harmonization of GeoTools

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http://www.geotoolkit.org/http://www.geotoolkit.org/


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Sextante

Spatial data analysis library

300+ algorithms for vecor- and raster-data

Interoperable with JTS

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http://sextante.forge.osor.eu/http://sextante.forge.osor.eu/


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GeoServer

Most widely used WMS/WFS/WCS server

Very active community

DeegreeSupports WMS, WFS, WCS, WPSSmaller community

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http://www.deegree.org/http://www.deegree.org/http://www.geoserver.org/http://www.deegree.org/http://www.deegree.org/http://www.geoserver.org/http://www.geoserver.org/


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OpenLayers

Most commonly used JavaScript client-framework

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GeoMajas

Integrated application framework (back- & front-end)

Uses GWT for client UI

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http://www.geomajas.org/http://www.openlayers.org/http://www.geomajas.org/http://www.geomajas.org/http://www.openlayers.org/http://www.openlayers.org/


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Leaflet

Mobile web apps (esp. iOS)

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http://leaflet.cloudmade.com/http://leaflet.cloudmade.com/


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OSGEOOSGeo was created to support the collaborative development of open sourcgeospatial software, and promote its widespread use

Projects: GeoTools, GeoServer, ....

FOSS4G: global conference focused on F/OSS for Geospatial

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http://www.osgeo.org/http://www.osgeo.org/


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OpenStreetMap (OSM)

Global dataset (roads, admin. boundaries, rivers, ...)

Community-created

Creative Commons Attribution-ShareAlike 2.0 license

Variable quality

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http://creativecommons.org/licenses/by-sa/2.0/http://creativecommons.org/licenses/by-sa/2.0/


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GeometryUserType for JTS Geometry

SpatialRestrictions API

HQL Spatial Functions

Marshalling/unmarshalling to DB-specific formats

Service Provider Interface for SpatialDialectProviders

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Oracle Spatial (SDOGEOMETRY)

Postgresql/Postgis

MySQL

Microsoft SQL Server 2008

GeoDB (H2)

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HS 1.1.x

Supports Hibernate 3.6

Adds dwithin(), transform() methods

HS 4

Module of Hibernate Core (4.1 probably)

JTS and Geolatte-geom

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brujug presentation 2011-12-15

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