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[Geotools-commits] svn - r23119 - geotools/trunk/gt/doc/user_manual/C
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From: <ac...@sv...> - 2006-11-29 14:19:50
|
Author: acuster
Date: 2006-11-29 06:17:41 -0800 (Wed, 29 Nov 2006)
New Revision: 23119
Modified:
geotools/trunk/gt/doc/user_manual/C/0_blankChapter.xml
geotools/trunk/gt/doc/user_manual/C/libJTS.xml
Log:
Docs:outline libJTS chapter;tweak blank
Modified: geotools/trunk/gt/doc/user_manual/C/0_blankChapter.xml
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- geotools/trunk/gt/doc/user_manual/C/0_blankChapter.xml 2006-11-29 11:=
51:16 UTC (rev 23118)
+++ geotools/trunk/gt/doc/user_manual/C/0_blankChapter.xml 2006-11-29 14:=
17:41 UTC (rev 23119)
@@ -32,10 +32,19 @@
<title>Warnings</title>
=20
<warning>
+ <title></title>
<para>
+ =20
</para>
</warning>
=20
+ <warning>
+ <title></title>
+ <para>
+ =20
+ </para>
+ </warning>
+ =20
</sect2>
=20
=20
@@ -57,7 +66,7 @@
</para>
=20
<table>
-<title>Fundamental Terminology</title>
+<title>Packages and their use</title>
<tgroup cols=3D"2">
<thead>
<row>
Modified: geotools/trunk/gt/doc/user_manual/C/libJTS.xml
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- geotools/trunk/gt/doc/user_manual/C/libJTS.xml 2006-11-29 11:51:16 UT=
C (rev 23118)
+++ geotools/trunk/gt/doc/user_manual/C/libJTS.xml 2006-11-29 14:17:41 UT=
C (rev 23119)
@@ -1,70 +1,139 @@
<chapter id=3D"chapter-geomJTS">
<title>Library: JTS</title>
+
<!-- Top Level, a description with the chapter TOC -->
<para>
- This chapter explains the geometric model used in &geot;. The geomet=
ric model=20
- provides the structure through which the Geotools library defines th=
e spatial=20
- properties of its Features.
+ This chapter explains one of the two geometric models used in the Ge=
otools
+ library. Geotools uses the Java Topology Suite (JTS) library directl=
y for=20
+ its implementation of feature geometries, that is, for the geometric=
=20
+ representation of the spatial presence of real world entities. Howev=
er,=20
+ because the JTS library operates strictly in an orthogonal, two-dime=
nsional,=20
+ euclidean space, Geotools uses a separate geometric system to repres=
ent=20
+ positions and extents on the earth's surface. This chapter explains =
the use=20
+ by Geotools of the JTS geometric library;=20
+ <xref linkend=3D"chapter-geomGeoAPI"/> explains the use of the geo-r=
eferenced=20
+ geometric model defined in GeoAPI interfaces.
</para>
-
- <warning>
+ =20
+ =20
+ <!-- Critical Warnings -->
+ =20
+ =20
+ <sect1 id=3D"sect-geomJTS-intro">
+ <title>Introduction</title>
+ =20
+ <!--Overview and when not to read the chapter -->
<para>
- &geot; uses the Java Topology Suite (JTS) library for all of its g=
eometric
- representation. Note also, that all access is done directly into J=
TS classes
- rather than working through an abstract layer of interfaces. The &=
geot;=20
- project intends eventually to switch to use an internal geometric=20
- representation and to develop and use a standard set of GeoAPI int=
erfaces.
+ Geotools currently uses the Java Topology Suite (JTS) library to=20
+ represent the spatial characteristics of the geospatial features t=
hrough=20
+ which Geotools represents real world entities. JTS provides a powe=
rful,=20
+ complete, numerically robust implementation of the geometric model=
=20
+ required by the Simple Features for SQL standard.=20
</para>
- </warning>
-
- <note>
+ =20
+ =20
+ <note>
+ <title>Users are not required to work directly with geometries.</t=
itle>
+ <para>
+ Most development using &geot; library can be done at a higher le=
vel than=20
+ operating directly on the geometric model itself. The informatio=
n in=20
+ this section may be most relevant simply as background for the u=
se of=20
+ operations at a higher level.
+ </para>
+ </note>
+ =20
<para>
- Most development using &geot; library can be done at a higher leve=
l than=20
- opertating directly on the geometric model itself. The information=
in this=20
- section may be most relevant simply as background for the use of o=
perations=20
- at a higher level.
+ The JTS library was developed by Vivid Solutions with the intent t=
o create=20
+ a spatial model sufficiently rich to fully describe 'Simple Featur=
es'=20
+ according to the Simple Features Specification for SQL (SFS) of th=
e=20
+ Open Geospatial Consortium (OpenGIS or OGC). Since Geotools shared=
the=20
+ same intent and because of the quality and progress of the JTS lib=
rary=20
+ when the Geotools project began, the Geotools project decided to r=
ely=20
+ entirely on the JTS project.
</para>
- </note>
+ =20
+ <para>
+ The 'Simple Features' spatial model supported by the JTS project i=
s=20
+ fundamentally a two dimensional spatial model in a Euclidean space=
with=20
+ orthogonal axes. While, as documented below, the JTS library provi=
des the=20
+ space for three numeric values in its fundamental coordinate data=20
+ structure and the library allows the inclusion of a Spatial Refere=
nce=20
+ Identification (SRID) number in an optional user data object in th=
e=20
+ fundamental geometric data structures, both the third ('z') coordi=
nate and=20
+ the SRID are ignored in all JTS operations.=20
+ </para>
=20
=20
-
- <sect1 id=3D"sect-geomJTS-intro">
- <title>Geometries in Geotools</title>
-
<para>
- The core geometric model of &geot; uses lightweight objects.
- <figure id=3D"fig-geotools-geomModel">
- <title>The Geotools Geometric Model.</title>
- <screenshot>
- <mediaobject>
- <imageobject>
- <imagedata fileref=3D"figures/geotools-geomModel.png"=20
- format=3D"PNG" />
- </imageobject>
- <textobject>
- <phrase>
- An image of the geometric model containing only JTS.
- </phrase>
- </textobject>
- <caption>
- <para>
- &geot; does not use its own geometric model but instead relies on=
=20
- the JTS library.
- </para>
- </caption>
- </mediaobject>
- </screenshot>
- </figure>
+ TODO: Discuss here precision, replaceable coordinates, the complex=
ity=20
+ in the details...
</para>
-
- <sect2 id=3D"sect-geomJTS-intro-core">
- <title>The core components of Geotools Geometries</title>
-
+ =20
+ <para>
+ This chapter discusses version 1.7.2 of the JTS library.
+ </para>
+ =20
+ <para>
+ While the JTS library has provided a powerful and complete impleme=
ntation=20
+ of the spatial model defined in the Simple Features for SQL specif=
ication,=20
+ the Geotools project plans to migrate to the more complex spatial =
model=20
+ described by the 19107 Standard "Spatial Schema" of the Internatio=
nal=20
+ Organization for Standardization (ISO) which will be essentially i=
dentical=20
+ to the new Abstract Specification, Topic 1: "Feature Geometry" of =
the=20
+ Open Geospatial Consortium (OpenGIS). This new
+ standard requires true three dimensional geometric structures, req=
uires=20
+ more complex geometric constructs such as curves defined as Bezier=
=20
+ structures, and defines more advanced spatial operators. The Geoto=
ols=20
+ project plans to develop this new geometric model in two parts, on=
e=20
+ defining, as part of the=20
+ GeoAPI project, a set of interfaces into the geometric model and a=
second=20
+ implementing the interfaces in a module of the Geotools project it=
self.
+ </para>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-intro-usage">
+ <title>Usage</title>
+ =20
<para>
- TODO: Make a table... Core classes;API;Modules;Packages;Create
</para>
-
+ =20
+ </sect2>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-intro-warnings">
+ <title>Warnings</title>
+ =20
+ <warning>
+ <title>Geotools will move to GeoAPI geometries</title>
+ <para>
+ While Geotools currently uses the JTS library for its geometri=
c=20
+ representation, the project plans to develop a full set of=20
+ interfaces in the GeoAPI project, implement these interfaces i=
n=20
+ a Geotools module, and move the spatial description of feature=
s=20
+ to this new geometric model.
+ </para>
+ </warning>
+ =20
+ <warning>
+ <title></title>
+ <para>
+ =20
+ </para>
+ </warning>
+ =20
+ </sect2>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-intro-model">
+ <title>Instance Object Model</title>
+ =20
<para>
+ </para>
+ =20
+ <para>
<figure id=3D"fig-geotools-geomExample">
<title>An example geometry.</title>
<screenshot>
@@ -87,62 +156,278 @@
</screenshot>
</figure>
</para>
-
+ =20
</sect2>
-
- <sect2 id=3D"sect-geomJTS-JTS">
- <title>The Java Topology Suite (JTS)</title>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-intro-code">
+ <title>Code Layout</title>
=20
<para>
- The JTS library was developed by Vivid Solutions with the intent =
to create a spatial model sufficiently rich to fully describe 'Simple Fea=
tures' according to the Simple Features Specification for SQL (SFS) of th=
e Open Geospatial Consortium (OpenGIS or OGC). Since Geotools shared the=
same intent and because of the quality and progress of the JTS library w=
hen the Geotools project began, the Geotools project decided to rely enti=
rely on the JTS project.
</para>
=20
- <para>
- The 'Simple Features' spatial model supported by the JTS project=
is fundamentally a two dimensional spatial model in a Euclidean space wi=
th orthogonal axes. While, as documented below, the JTS library provides =
the space for three numeric values in its fundamental coordinate data str=
ucture and the library allows the inclusion of a Spatial Reference Identi=
fication (SRID) number in an optional user data object in the fundamental=
geometric data strcutures, both the third ('z') coordinate and the SRID =
are ignored in all JTS operations. TODO: Verify again that this is correc=
t.
- </para>
+<table>
+<title>Packages and their use</title>
+<tgroup cols=3D"2">
+<thead>
+<row>
+ <entry>Package</entry>
+ <entry>Use</entry>
+</row>
+</thead>
+<tbody>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.algorithm
+ </para>
+ </entry>
+ <entry>
+ <para>Base computational geometry methods
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.geom
+ </para>
+ </entry>
+ <entry>
+ <para>Core classes for users
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.geomgraph
+ </para>
+ </entry>
+ <entry>
+ <para>Topological methods on planar graphs
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.index
+ </para>
+ </entry>
+ <entry>
+ <para>Several indexing systems
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.io
+ </para>
+ </entry>
+ <entry>
+ <para>Well Known Text formatting and parsing
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.linearref
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.noding
+ </para>
+ </entry>
+ <entry>
+ <para>Methods to add nodes to geometries
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.operation
+ </para>
+ </entry>
+ <entry>
+ <para>Complex geometric operations
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.planargraph
+ </para>
+ </entry>
+ <entry>
+ <para>Base elements of planar graphs
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.precision
+ </para>
+ </entry>
+ <entry>
+ <para>Alternative precision model elements
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.simplify
+ </para>
+ </entry>
+ <entry>
+ <para>Geometric simplification algorithms
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>com.vividsolutions.jts.util
+ </para>
+ </entry>
+ <entry>
+ <para>Utility classes
+ </para>
+ </entry>
+</row>
+</tbody>
+</tgroup>
+</table>
=20
- <para>
- TODO: Discuss here precision, replaceable coordinates, the compl=
exity=20
- in the details...
- </para>
-
</sect2>
=20
- <sect2 id=3D"sect-geomJTS-future">
- <title>Future work</title>
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-intro-keyClasses">
+ <title>Key Classes</title>
=20
<para>
- The Geotools project eventually intents to migrate to a more com=
plex spatial model described by the International Organization for Standa=
rdization (ISO) 19107 Standard "Spatial Schema" which will be essentially=
identical to the new OpenGIS Abstract Specification, Topic 1: "Feature G=
eometry". This new standard introduces more complex geometry, more advanc=
ed spatial operators and will involve a tremendous amount of work.
+ The core classes in the JTS library are in the Geometry class hi=
erarchy=20
+ along with the Envelope and Coordinate classes. All of the inter=
faces to
+ these classes are directly in the JTS library packages themselve=
s.
+ =20
</para>
+ =20
+<table>
+<title>Key Classes</title>
+<tgroup cols=3D"3">
+<thead>
+<row>
+ <entry>Class</entry>
+ <entry>Creation</entry>
+ <entry>Use</entry>
+</row>
+</thead>
+<tbody>
+<row>
+ <entry>
+ <para>Coordinate
+ </para>
+ </entry>
+ <entry>
+ <para>new(.)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>Envelope
+ </para>
+ </entry>
+ <entry>
+ <para>new(.)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>Geometry
+ </para>
+ </entry>
+ <entry>
+ <para><emphasis role=3D"italic">abstract</emphasis>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>Point
+ </para>
+ </entry>
+ <entry>
+ <para>myGeomFactory.createPoint(.)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+<row>
+ <entry>
+ <para>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ </para>
+ </entry>
+</row>
+</tbody>
+</tgroup>
+</table>
=20
</sect2>
-
+ =20
</sect1>
-
-
-
-
-
-
+ =20
+ =20
+ =20
+ =20
<sect1 id=3D"sect-geomJTS-runThrough">
- <title>A quick run through</title>
+ <title>Run Through</title>
=20
<para>
- =20
+ =20
</para>
- <!--
+ <!--
<sect2 id=3D"">
<title></title>
=20
<para>
+ =20
</para>
=20
</sect2>
- -->
+ -->
</sect1>
-
-
-
+ =20
+ =20
+ =20
+ =20
<sect1 id=3D"sect-geomJTS-resources">
<title>Resources</title>
=20
@@ -217,16 +502,26 @@
</para>
=20
</sect2>
+ <!--
+ <sect2 id=3D"">
+ <title></title>
=20
+ <para>
+ =20
+ </para>
+
+ </sect2>
+ -->
</sect1>
-
-
-
+ =20
+ =20
+ =20
+ =20
<sect1 id=3D"sect-geomJTS-practical">
- <title>Practical Code Information</title>
+ <title>Practical Information </title>
=20
<para>
- =20
+ =20
</para>
=20
<sect2 id=3D"sect-geomJTS-practical-utilClass">
@@ -254,190 +549,197 @@
=20
</sect2>
=20
-
</sect1>
+ =20
+ =20
+ =20
+ =20
+ <sect1 id=3D"sect-geomJTS-classes">
+ <title>Principal Classes</title>
=20
-
-
- <sect1 id=3D"sect-geomJTS-Coordinate">
- <title>Coordinates</title>
-
<para>
- JTS Coordinate objects are lightweight entities with fields=20
- (.x, .y, and .z), each holding a 'double' value.
- <figure id=3D"fig-geotools-geomJTS-coord">
- <title>JTS Coordinates.</title>
- <screenshot>
- <mediaobject>
- <imageobject>
- <imagedata fileref=3D"figures/JTS_Coordinate.png"=20
- format=3D"PNG" />
- </imageobject>
- <textobject>
- <phrase>
- An image of the JTS Coordinate class.
- </phrase>
- </textobject>
- <caption>
- <para>
- Key aspects of the JTS Coordinate class.
- </para>
- </caption>
- </mediaobject>
- </screenshot>
- </figure>
+ =20
</para>
+ =20
+ <sect2 id=3D"sect-geomJTS-Coordinate">
+ <title>Coordinates</title>
=20
- <warning>
- <title>JTS Operations are 2D only</title>
<para>
- While JTS allows the inclusion of a thrid 'z' coordinate, <empha=
sis>this coordinate is never used in JTS operations</emphasis>! JTS perfo=
rms all of its operations in the projected x-y plane.=20
+ JTS Coordinate objects are lightweight entities with fields=20
+ (.x, .y, and .z), each holding a 'double' value.
+ <figure id=3D"fig-geotools-geomJTS-coord">
+ <title>JTS Coordinates.</title>
+ <screenshot>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref=3D"figures/JTS_Coordinate.png"=20
+ format=3D"PNG" />
+ </imageobject>
+ <textobject>
+ <phrase>
+ An image of the JTS Coordinate class.
+ </phrase>
+ </textobject>
+ <caption>
+ <para>
+ Key aspects of the JTS Coordinate class.
+ </para>
+ </caption>
+ </mediaobject>
+ </screenshot>
+ </figure>
</para>
- </warning>
=20
- <para>
- Instances of these Coordinate values provide the spatial informati=
on for the JTS Geometry objects. Construction of Coordinate objects invol=
ves simple calls to the class constructor methods.
- </para>
+ <warning>
+ <title>JTS Operations are 2D only</title>
+ <para>
+ While JTS allows the inclusion of a thrid 'z' coordinate, <emp=
hasis>this coordinate is never used in JTS operations</emphasis>! JTS per=
forms all of its operations in the projected x-y plane.=20
+ </para>
+ </warning>
=20
-
- <!--
- <sect2 id=3D"">
- <title></title>
-
<para>
+ Instances of these Coordinate values provide the spatial informa=
tion for the JTS Geometry objects. Construction of Coordinate objects inv=
olves simple calls to the class constructor methods.
</para>
=20
+
</sect2>
- -->
- </sect1>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-Envelope">
+ <title>Envelopes</title>
=20
+ <para>
+ JTS Envelope objects are axis parallel, rectangular regions of =
the x-y plane. Instances of this class are used expecially to define the =
outer extent of each JTS Geometry and every Geotools Feature using the co=
ncept of a 'bounding-box' which is an axis-parallel, rectilinear region.
+ <figure id=3D"fig-geotools-geomJTS-envelope">
+ <title>JTS Envelope.</title>
+ <screenshot>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref=3D"figures/JTS_Envelope.png"=20
+ format=3D"PNG" />
+ </imageobject>
+ <textobject>
+ <phrase>
+ An image of the JTS Envelope class.
+ </phrase>
+ </textobject>
+ <caption>
+ <para>
+ Key aspects of the JTS Envelope class.
+ </para>
+ </caption>
+ </mediaobject>
+ </screenshot>
+ </figure>
+ </para>
=20
+ <para>
+ Construction of Envelope objects involves simple calls to the c=
lass constructor methods.
+ </para>
=20
- <sect1 id=3D"sect-geomJTS-Envelope">
- <title>Envelopes</title>
+ </sect2>
+ =20
+ =20
+ =20
+ <sect2 id=3D"sect-geomJTS-geometry">
+ <title>Geometries</title>
=20
- <para>
- JTS Envelope objects are axis parallel, rectangular regions of th=
e x-y plane. Instances of this class are used expecially to define the ou=
ter extent of each JTS Geometry and every Geotools Feature using the conc=
ept of a 'bounding-box' which is an axis-parallel, rectilinear region.
- <figure id=3D"fig-geotools-geomJTS-envelope">
- <title>JTS Envelope.</title>
- <screenshot>
- <mediaobject>
- <imageobject>
- <imagedata fileref=3D"figures/JTS_Envelope.png"=20
- format=3D"PNG" />
- </imageobject>
- <textobject>
- <phrase>
- An image of the JTS Envelope class.
- </phrase>
- </textobject>
- <caption>
- <para>
- Key aspects of the JTS Envelope class.
- </para>
- </caption>
- </mediaobject>
- </screenshot>
- </figure>
- </para>
+ <para>
+ JTS Geometry objects define the fundamental spatial elements in =
the Geotools Geometric Model. JTS Geometry objects include Point, LineStr=
ing, with a LinearRing which has a common end-point coordinate, Polygon, =
and Collection sub-classes, the latter further sub-classed into MultiPoin=
t, MultiLineString, and MultiPolygon.
+ <figure id=3D"fig-geotools-geomJTS-geom">
+ <title>JTS Envelope.</title>
+ <screenshot>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref=3D"figures/JTS_Geometry.png"=20
+ format=3D"PNG" />
+ </imageobject>
+ <textobject>
+ <phrase>
+ An image of the JTS Geometry class.
+ </phrase>
+ </textobject>
+ <caption>
+ <para>
+ Key aspects of the JTS Geometry class.
+ </para>
+ </caption>
+ </mediaobject>
+ </screenshot>
+ </figure>
+ </para>
=20
- <para>
- Construction of Envelope objects involves simple calls to the cla=
ss constructor methods.
- </para>
-
-
- <!--
- <sect2 id=3D"">
- <title></title>
-
<para>
+ Conceptually, Geometry objects have, as internal fields, Coordin=
ate objects to define the spatial nature of the Geometry, a type element =
describing the nature of the Geometry, an Envelope object defining the ex=
tent of the Geometry, and an optional User Data object element in which a=
ny object can be stored for programmatic convenience. Geometry objects in=
clude convenience methods such as the toText() method which converts any =
Geometry instance into an equivalent representation in Well Known Text (W=
KT) a formally defined representation of the spatial definintion of the G=
eometry object using a Java String. Geometry objects also include a numbe=
r of spatial operator methods such as two returing Java double values, di=
stance() and area(), and two returning new Geometry objects, convexHull()=
and buffer(). Construction of Geometry objects is done through the creat=
ion of a GeometryFactory object as explained in the first tutorial.
</para>
-
+ =20
</sect2>
- -->
+ =20
</sect1>
+ =20
+ =20
+ =20
+ =20
+ <sect1 id=3D"sect-geomJTS-tutorial">
+ <title>Tutorial</title>
=20
-
-
- <sect1 id=3D"sect-geomJTS-geometry">
- <title>Geometries</title>
-
<para>
- JTS Geometry objects define the fundamental spatial elements in th=
e Geotools Geometric Model. JTS Geometry objects include Point, LineStrin=
g, with a LinearRing which has a common end-point coordinate, Polygon, an=
d Collection sub-classes, the latter further sub-classed into MultiPoint,=
MultiLineString, and MultiPolygon.
- <figure id=3D"fig-geotools-geomJTS-geom">
- <title>JTS Envelope.</title>
- <screenshot>
- <mediaobject>
- <imageobject>
- <imagedata fileref=3D"figures/JTS_Geometry.png"=20
- format=3D"PNG" />
- </imageobject>
- <textobject>
- <phrase>
- An image of the JTS Geometry class.
- </phrase>
- </textobject>
- <caption>
- <para>
- Key aspects of the JTS Geometry class.
- </para>
- </caption>
- </mediaobject>
- </screenshot>
- </figure>
+ The "gt/demo/geomJTS/" directory has a number of tutorials which m=
ight be=20
+ useful to understand the JTS library and the &geot; geometry model=
.
</para>
-
- <para>
- Conceptually, Geometry objects have, as internal fields, Coordinat=
e objects to define the spatial nature of the Geometry, a type element de=
scribing the nature of the Geometry, an Envelope object defining the exte=
nt of the Geometry, and an optional User Data object element in which any=
object can be stored for programmatic convenience. Geometry objects incl=
ude convenience methods such as the toText() method which converts any Ge=
ometry instance into an equivalent representation in Well Known Text (WKT=
) a formally defined representation of the spatial definintion of the Geo=
metry object using a Java String. Geometry objects also include a number =
of spatial operator methods such as two returing Java double values, dist=
ance() and area(), and two returning new Geometry objects, convexHull() a=
nd buffer(). Construction of Geometry objects is done through the creatio=
n of a GeometryFactory object as explained in the first tutorial.
- </para>
- <!--
+ <!--
<sect2 id=3D"">
<title></title>
=20
<para>
+ =20
</para>
=20
</sect2>
- -->
+ -->
</sect1>
+ =20
+ =20
+ =20
+ =20
+ <sect1 id=3D"sect-geomJTS-readon">
+ <title>Reading More</title>
=20
-
- <sect1 id=3D"sect-geomJTS-tutorials">
- <title>Tutorials</title>
-
<para>
- The "gt/demo/geomJTS/" directory has a number of tutorials which m=
ight be=20
- useful to understand the JTS library and the &geot; geometry model=
.
+ =20
</para>
- <!--
+ <!--
<sect2 id=3D"">
<title></title>
=20
<para>
+ =20
</para>
=20
</sect2>
- -->
+ -->
</sect1>
+ =20
+ =20
+ =20
+ =20
+ <sect1 id=3D"sect-geomJTS-extending">
+ <title>Extending</title>
=20
-
-
- <sect1 id=3D"sect-geomJTS-readCode">
- <title>Reading more Code</title>
-
<para>
- JTS geometries are used throughout the &geot; code base. Some espe=
cially=20
- interesting areas to read are: TODO
+ =20
</para>
- <!--
+ <!--
<sect2 id=3D"">
<title></title>
=20
<para>
+ =20
</para>
=20
</sect2>
- -->
+ -->
</sect1>
=20
</chapter>
|