Coordinate Transformation Service - Revision history

Mentaer at 21:19, 19 November 2011

2011-11-19T21:19:02Z

Mentaer at 21:18, 19 November 2011

2011-11-19T21:18:30Z

Michaudm at 14:25, 29 October 2011

2011-10-29T14:25:06Z

Michaudm at 14:20, 29 October 2011

2011-10-29T14:20:56Z

Michaudm at 14:13, 29 October 2011

2011-10-29T14:13:13Z

Michaudm: Created page with ''''What a Coordinate Reference System is ?''' Coordinate Reference Systems are of 3 main sorts : - Cartesian (not much used except by geodesian and during transformat…'

2011-10-29T11:31:56Z

Created page with '<Big>'''What a Coordinate Reference System is ?'''</Big> Coordinate Reference Systems are of 3 main sorts : - Cartesian (not much used except by geodesian and during transformat…'

New page

<Big>'''What a Coordinate Reference System is ?'''</Big>

Coordinate Reference Systems are of 3 main sorts :
- Cartesian (not much used except by geodesian and during transformation processes)
- Geographic (longitude, latitude, and sometimes elevation or height above ellipsoid)
- Projected (used for cartographic purposes, there are dozens of possible projection)

Coordinate Reference System are mainly defined by
- A Datum (WGS84, ETRS, ED50...) : mandatory for any CRS
- An Ellipsoid : mandatory for Geographic and Projected CRS
- A Prime Meridian : mandatory for Geographic and Projected CRS
- A projection : mandatory for Projected CRS

There is a well established CRS database called EPSG, including definition of hundreds of CRS.

<Big>'''Coordinate Transformation Service'''</Big>

There is popular and mature CRS transformation tool called [Proj4 http://trac.osgeo.org/proj/] which is used by
- PostGIS (spatial database)
- OGR2OGR (a popular command line tool able to change coordinates and/or data format of a dataset)

<Big>'''Coordinate Transformation Service in/from Java'''</Big>

'''GeoAPI'''
It is a library including java interfaces conforming OGC Standards for Coordinate Transformation Service and some other topics.
At the origin, it has been developped to make libraries like OpenJUMP and Geotools interoperable.
Today, GeoToolKit is the only java library implementing the GeoAPI, but adapters have been developed for Proj4 to prove GeoAPI can be a general interface for any CTS implementation.

'''GeoTools and GeoToolKit'''
GeoTools has developped a pure java Coordinate Transformation Service. It has been a GeoAPI implementation for a long time, but it is no more.
Ede has developped a [OpenJUMP PlugIn] which makes GeoTools CTS accessible from OpenJUMP. It is based on a quite old version of GeoTools.
GeoToolKit is a fork of GeoTools. GeoToolKit is still a strict implementation of GeoAPI.
JhLabs has ported Proj4 code into Java. It is not a complete implementation of GeoAPI and has much less classes than GeoTools or GeoToolKit. It is available from two places :
- As Proj4J, on tutsiat website, the site of M. Davis who is maintaining the code
- As JMapProjLib, on sourceforge, maintained by B. Jenny

'''IGOR'''
ISA has developped a thin wrapper making OGR2OGR available from java (and from SkyJUMP).
It is Mainly a java UI calling OGR2OGR.exe
SkyJUMP com/isa/jump/plugin/igor package contains 4 classes which may be able to port IGOR to OpenJUMP quite easily.

''CTS'''

@@ Line 3: / Line 3: @@
 For a user guide of how to transform a layer with OpenJUMP, see [[CTS Extension]].
-<h2>'''What a Coordinate Reference System is ?'''</h2>
+<h2>'''What is a Coordinate Reference System (CRS)?'''</h2>
 A Coordinate Reference System is a coordinate system that enables every location on the Earth to be specified by a set of numbers

@@ Line 8: / Line 8: @@
 It can be of 3 main sorts :
-* Cartesian (not much used except by geodesian and during transformation processes)
+* Cartesian - e.g. x,y,z - not much used except by geodesian and during transformation processes
-* Geographic (longitude, latitude, and sometimes elevation or height above ellipsoid)
+* Geographic - e.g. longitude, latitude, and sometimes elevation or height above ellipsoid
-* Projected (used for cartographic purposes, there are dozens of possible projection)
+* Projected - e.g. x-North, y-East - used for cartographic purposes, there are dozens of possible projection
 Coordinate Reference System are defined by :
@@ Line 25: / Line 24: @@
 * [http://www.geoapi.org/3.0/javadoc/org/opengis/referencing/doc-files/WKT.html WKT (Well Known Text)] : there is a format specified by OGC and several variants (like ESRI proj files) introducing compatibility problems.
 * proj text file used by the Proj4 library where each CRS is defined on a single line
-* EPSG database (using access, hsqldb or h2 database)
+* EPSG database (using MS Access, hsql database or h2 database)
 <h2>'''Coordinate Transformation Service library in non java language'''</h2>
-There is popular and mature CRS transformation tool called [http://trac.osgeo.org/proj/ Proj4 ] which is used by
+There is popular and mature CRS transformation tool called [http://trac.osgeo.org/proj/ Proj4] which is used by
 * PostGIS (spatial database)
 * ogr2ogr, based on the [http://www.gdal.org/ogr/ OGR] library (a popular command line tool able to change coordinates and/or data format of a dataset)
@@ Line 39: / Line 38: @@
 It is a library including java interfaces conforming OGC Standards for Coordinate Transformation Service and some other topics.
 At the origin, it has been developped to make libraries like OpenJUMP and Geotools interoperable.
-Today, GeoToolKit is the only java library implementing the GeoAPI, but adapters have been developed for Proj4 to prove GeoAPI can be a general interface for any CTS implementation.
+Today, GeoToolKit is the only java library implementing the GeoAPI, but adapters have been developed for Proj4 so the GeoAPI can be a general interface for any CTS implementation.

@@ Line 3: / Line 3: @@
 For a user guide of how to transform a layer with OpenJUMP, see [[CTS Extension]].
-<Big>'''What a Coordinate Reference System is ?'''</Big>
+<h2>'''What a Coordinate Reference System is ?'''</h2>
 A Coordinate Reference System is a coordinate system that enables every location on the Earth to be specified by a set of numbers
 It can be of 3 main sorts :
 * Cartesian (not much used except by geodesian and during transformation processes)
@@ Line 11: / Line 12: @@
 * Projected (used for cartographic purposes, there are dozens of possible projection)
-'''Coordinate Reference System are defined by'''
 * A Datum (WGS84, ETRS, ED50...) : mandatory for any CRS
 * An Ellipsoid and a Prime Meridian : mandatory for Geographic and Projected CRS
 * A Projection : mandatory for Projected CRS
 There is a well established CRS registry called [http://www.epsg-registry.org/ EPSG], including definitions of hundreds of CRS.
 Most widely used formats to describe CRS are :
@@ Line 23: / Line 27: @@
 * EPSG database (using access, hsqldb or h2 database)
+<h2>'''Coordinate Transformation Service library in non java language'''</h2>
 There is popular and mature CRS transformation tool called [http://trac.osgeo.org/proj/ Proj4 ] which is used by
@@ Line 30: / Line 33: @@
 * ogr2ogr, based on the [http://www.gdal.org/ogr/ OGR] library (a popular command line tool able to change coordinates and/or data format of a dataset)
+<h2>'''Coordinate Transformation Service in/from Java'''</h2>
 '''[http://www.opengeospatial.org/standards/geoapi GeoAPI]'''

← Older revision		Revision as of 14:20, 29 October 2011
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		+	This page is intended for OpenJUMP and Coordinate Transformation Service developpers.
		+
		+	For a user guide of how to transform a layer with OpenJUMP, see [[CTS Extension]].
		+
	<Big>'''What a Coordinate Reference System is ?'''</Big>		<Big>'''What a Coordinate Reference System is ?'''</Big>