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/Src/Dependencies/Boost/libs/geometry/doc/doxy/doxygen_input/pages/doxygen_examples.hpp

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  1// Boost.Geometry (aka GGL, Generic Geometry Library)
  2//
  3// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands.
  4// Copyright (c) 2008-2011 Bruno Lalande, Paris, France.
  5// Use, modification and distribution is subject to the Boost Software License,
  6// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  7// http://www.boost.org/LICENSE_1_0.txt)
  8
  9#ifndef _DOXYGEN_EXAMPLES_HPP
 10#define _DOXYGEN_EXAMPLES_HPP
 11
 12
 13/*!
 14
 15
 16\example 01_point_example.cpp
 17In most cases the documentation gives small examples of how to use the algorithms or classes.
 18The point example is a slightly larger example giving an idea of how to use different
 19algorithms from the library, related to points. It shows
 20- the usage of include files
 21- how to declare points, using different coordinate types
 22- how to construct points, specifying coordinates, initializing to zero or to infinite
 23- how to compare points to each other
 24- how points can be streamed as OGC text
 25- calculating the distance from point to point
 26
 27
 28*/
 29
 30
 31//---------------------------------------------------------------------------------------------------
 32
 33/*!
 34\example 02_linestring_example.cpp
 35The linestring example shows how linestrings can be declared and used and shows some more algorithms.
 36One of the important concepts of the Generic Geometry Library is that it is totally built upon the standard
 37library, using the standard containers such as std::vector.
 38
 39A linestring is, as explained elsewhere in this documentation, not much more than a vector of points.
 40Most algorithms run on linestrings, but can also run on any iterator pair. And all algorithms
 41on std::vector can be used on geometry::linestring.
 42
 43The sample shows this, shows some algorithms:
 44- geometry::envelope
 45- geometry::length
 46- geometry::distance
 47- geometry::simplify
 48- geometry::for_each
 49- geometry::intersection
 50
 51This documentation illustrates the simplify algorithm and the intersection algorithm with some pictures.
 52
 53The simplify algorithm simplifies a linestring. Simplification means that the less important points
 54are removed from the line and that the points that are most important for the shape of a line are
 55kept. Simplification is done using the well known Douglas Peucker algorithm. The library user can
 56specify the distance or tolerance, which indicates how much the linestring should be simplified.
 57
 58The image below shows the original and simplified linestring:
 59\image html simplify_linestring.png
 60The blue line is the original linestring; the red line is the simplified line which has one point less.
 61In geographical applications simplification can reduce a linestring to its basic form containing only
 6210% of its original points.
 63
 64The intersection algorithm intersects two geometries which each other, delivering a third geometry.
 65In the case of the example a linestring is intersected with a box. Intersection with a box is often
 66called a clip. The image below illustrates the intersection.
 67\image html clip_linestring.png
 68The yellow line is intersected with the blue box.
 69The intersection result, painted in red, contains three linestrings.
 70*/
 71
 72//---------------------------------------------------------------------------------------------------
 73
 74/*!
 75\example 03_polygon_example.cpp
 76The polygon example shows some examples of what can be done with polygons in the Generic Geometry Library:
 77* the outer ring and the inner rings
 78* how to calculate the area of a polygon
 79* how to get the centroid, and how to get an often more interesting label point
 80* how to correct the polygon such that it is clockwise and closed
 81* within: the well-known point in polygon algorithm
 82* how to use polygons which use another container, or which use different containers for points and for inner rings
 83* how polygons can be intersected, or clipped, using a clipping box
 84
 85The illustrations below show the usage of the within algorithm and the intersection algorithm.
 86
 87The within algorithm results in true if a point lies completly within a polygon. If it lies exactly
 88on a border it is not considered as within and if it is inside a hole it is also not within the
 89polygon. This is illustrated below, where only the point in the middle is within the polygon.
 90
 91\image html within_polygon.png
 92
 93The clipping algorithm, called intersection, is illustrated below:
 94
 95\image html clip_polygon.png
 96
 97The yellow polygon, containing a hole, is clipped with the blue rectangle, resulting in a
 98multi_polygon of three polygons, drawn in red. The hole is vanished.
 99
100include polygon_example.cpp
101*/
102
103
104//---------------------------------------------------------------------------------------------------
105 /*!
106\example 06_a_transformation_example.cpp
107This sample demonstrates the usage of transformations in the Generic Geometry Library.
108Behind the screens this is done using with the uBLAS matrix/vector library.
109
110\example 06_b_transformation_example.cpp
111
112*/
113
114//---------------------------------------------------------------------------------------------------
115
116/*!
117\example 07_a_graph_route_example.cpp
118The graph route example shows how GGL can be combined with Boost.Graph. The sample does the following things:
119- it reads roads (included in the distribution, stored on disk in the form of a text file containing geometries and names)
120- it reads cities
121- it creates a graph from the roads
122- it connects each city to the nearest vertex in the graph
123- it calculates the shortest route between each pair of cities
124- it outputs the distance over the road, and also of the air
125- it creates an SVG image with the roads, the cities, and the first calculated route
126
127Note that this example is useful, but it is only an example. It could be built in many different ways.
128For example:
129- the roads/cities could be read from a database using SOCI, or from a shapefile using shapelib
130- it could support oneway roads and roads on different levels (disconnected bridges)
131- it currently uses tuples but that could be anything
132- etc
133
134The SVG looks like:
135\image html 07_graph_route_example_svg.png
136
137The output screen looks like:
138\image html 07_graph_route_example_text.png
139
140\example 07_b_graph_route_example.cpp
141
142
143*/
144
145
146//---------------------------------------------------------------------------------------------------
147 /*!
148\example c01_custom_point_example.cpp
149This sample demonstrates that custom points can be made as well. This sample contains many points, derived
150from boost::tuple, created from scratch, read only points, legacy points, etc.
151*/
152
153//---------------------------------------------------------------------------------------------------
154 /*!
155\example c02_custom_box_example.cpp
156Besides custom points, custom boxes are possible as shown in this example.
157*/
158
159//---------------------------------------------------------------------------------------------------
160/*
161\example c03_custom_linestring_example.cpp
162GPS tracks are shown in this example: a custom linestring with GPS points
163*/
164
165//---------------------------------------------------------------------------------------------------
166 /*!
167\example c04_a_custom_triangle_example.cpp
168The \b custom triangle \b example goes even further and implements a custom ring, where the area calculation
169algorithm is optimized for a triangle
170*/
171
172//---------------------------------------------------------------------------------------------------
173 /*!
174\example c04_b_custom_triangle_example.cpp
175This second custom triangle example shows an alternative implementation for a custom shape, showing a
176partial specialization for the area calculation.
177*/
178
179//---------------------------------------------------------------------------------------------------
180 /*!
181\example c05_custom_point_pointer_example.cpp
182This example shows how GGL can be used to adapt a pointer-to-a-point, used e.g. in a linestring
183*/
184
185//---------------------------------------------------------------------------------------------------
186 /*!
187\example c06_custom_polygon_example.cpp
188Showing a custom polygon (asked on the list during Formal Review)
189*/
190
191
192
193//---------------------------------------------------------------------------------------------------
194 /*!
195\example x01_qt_example.cpp
196This sample demonstrates that by usage of concepts, external geometries can be handled
197by GGL, just calling by a one-line registration macro. In this case for the Qt Widget Library.
198
199The example, code shown below, results in this window-output:
200\image html x01_qt_example_output.png
201*/
202
203
204
205
206
207//---------------------------------------------------------------------------------------------------
208 /*!
209\example x03_a_soci_example.cpp
210First example showing how to get spatial data from a database using SOCI and put them into GGL
211*/
212
213
214//---------------------------------------------------------------------------------------------------
215 /*!
216\example x03_b_soci_example.cpp
217Second example showing how to get polygons from a database using SOCI and put them into GGL, using WKT.
218*/
219
220
221//---------------------------------------------------------------------------------------------------
222 /*
223\example x03_c_soci_example.cpp
224Example showing how to get polygons from PostGIS using SOCI and use them in GGL through WKB
225*/
226
227
228//---------------------------------------------------------------------------------------------------
229 /*
230\example x03_d_soci_example.cpp
231Example showing how to get polygons from PostGIS using SOCI and use them in GGL through WKB
232
233*/
234
235#endif // _DOXYGEN_EXAMPLES_HPP