classogrlinestring.html

gdal库的学习文档

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<a class="anchor" name="f924e1027c6153fc3cc4040cab79e117"></a><!-- doxytag: member="OGRLineString::getDimension" ref="f924e1027c6153fc3cc4040cab79e117" args="() const" -->
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          <td class="memname">int OGRLineString::getDimension           </td>
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Get the dimension of this object.<p>
This method corresponds to the SFCOM IGeometry::GetDimension() method. It indicates the dimension of the object, but does not indicate the dimension of the underlying space (as indicated by <a class="el" href="classOGRGeometry.html#4a6fdd4df7c043558b5428d8f1c35b16">OGRGeometry::getCoordinateDimension()</a>).<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#94b633e1acd208c258ad49f8d4fd4104">OGR_G_GetDimension()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 for points, 1 for lines and 2 for surfaces. </dd></dl>

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Implements <a class="el" href="classOGRGeometry.html#266c427f00ea35fdc503393c210a115d">OGRGeometry</a>.
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<a class="anchor" name="bda61341d48aff2d374403c1cce69c56"></a><!-- doxytag: member="OGRLineString::clone" ref="bda61341d48aff2d374403c1cce69c56" args="() const" -->
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          <td class="memname"><a class="el" href="classOGRGeometry.html">OGRGeometry</a> * OGRLineString::clone           </td>
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Make a copy of this object.<p>
This method relates to the SFCOM IGeometry::clone() method.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#1725918932da7d59f9ee72829ac171fa">OGR_G_Clone()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>a new object instance with the same geometry, and spatial reference system as the original. </dd></dl>

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Implements <a class="el" href="classOGRGeometry.html#f2fe60f2bde104cb3eef16475f3f3cd8">OGRGeometry</a>.
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Reimplemented in <a class="el" href="classOGRLinearRing.html#33e70d13f0953a438417714ab8ebb299">OGRLinearRing</a>.
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<a class="anchor" name="958cec2e062c6372131139be247aecdb"></a><!-- doxytag: member="OGRLineString::empty" ref="958cec2e062c6372131139be247aecdb" args="()" -->
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          <td class="memname">void OGRLineString::empty           </td>
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Clear geometry information. This restores the geometry to it's initial state after construction, and before assignment of actual geometry.<p>
This method relates to the SFCOM IGeometry::Empty() method.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#90cc83b0a3052b8fbe2ed77a86323bf2">OGR_G_Empty()</a>. 
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Implements <a class="el" href="classOGRGeometry.html#1702b5b8142abe761061a6cd44e50b05">OGRGeometry</a>.
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<a class="anchor" name="10e1e99078d31aa7de43b1d930f27fc2"></a><!-- doxytag: member="OGRLineString::getEnvelope" ref="10e1e99078d31aa7de43b1d930f27fc2" args="(OGREnvelope *psEnvelope) const" -->
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          <td class="memname">void OGRLineString::getEnvelope           </td>
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          <td class="paramname"> <em>psEnvelope</em>          </td>
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Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#617a9c9ea85157661619a1d8f0a69cf9">OGR_G_GetEnvelope()</a>.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"></td><td valign="top"><em>psEnvelope</em>&nbsp;</td><td>the structure in which to place the results. </td></tr>
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Implements <a class="el" href="classOGRGeometry.html#a3d42b06ae6f7bbef6d1a2886da8d398">OGRGeometry</a>.
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<a class="anchor" name="22d28cc8ac3526c4a993957a57b75ce9"></a><!-- doxytag: member="OGRLineString::get_Length" ref="22d28cc8ac3526c4a993957a57b75ce9" args="() const" -->
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          <td class="memname">double OGRLineString::get_Length           </td>
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Returns the length of the curve.<p>
This method relates to the SFCOM ICurve::get_Length() method.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the length of the curve, zero if the curve hasn't been initialized. </dd></dl>

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Implements <a class="el" href="classOGRCurve.html#1eab84f4cae72cab2f861d8e72fc71a6">OGRCurve</a>.
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<a class="anchor" name="48a9e983559b88ecad0629db15f0c790"></a><!-- doxytag: member="OGRLineString::StartPoint" ref="48a9e983559b88ecad0629db15f0c790" args="(OGRPoint *) const " -->
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          <td class="memname">void OGRLineString::StartPoint           </td>
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          <td class="paramtype"><a class="el" href="classOGRPoint.html">OGRPoint</a> *&nbsp;</td>
          <td class="paramname"> <em>poPoint</em>          </td>
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Return the curve start point.<p>
This method relates to the SF COM ICurve::get_StartPoint() method.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>poPoint</em>&nbsp;</td><td>the point to be assigned the start location. </td></tr>
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Implements <a class="el" href="classOGRCurve.html#28510cf9de71e098b50d241f6ab99cd1">OGRCurve</a>.
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<a class="anchor" name="99daa05665aef02aa0601eb53af814c1"></a><!-- doxytag: member="OGRLineString::EndPoint" ref="99daa05665aef02aa0601eb53af814c1" args="(OGRPoint *) const " -->
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          <td class="memname">void OGRLineString::EndPoint           </td>
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Return the curve end point.<p>
This method relates to the SF COM ICurve::get_EndPoint() method.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>poPoint</em>&nbsp;</td><td>the point to be assigned the end location. </td></tr>
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Implements <a class="el" href="classOGRCurve.html#2e9e8e178c7e70efdecd1c50d95d537e">OGRCurve</a>.
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<a class="anchor" name="e6429dc0324367c33cf1a65b33e7d9c0"></a><!-- doxytag: member="OGRLineString::Value" ref="e6429dc0324367c33cf1a65b33e7d9c0" args="(double, OGRPoint *) const" -->
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          <td class="memname">void OGRLineString::Value           </td>
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          <td class="paramtype"><a class="el" href="classOGRPoint.html">OGRPoint</a> *&nbsp;</td>
          <td class="paramname"> <em>poPoint</em></td><td>&nbsp;</td>
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Fetch point at given distance along curve.<p>
This method relates to the SF COM ICurve::get_Value() method.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>dfDistance</em>&nbsp;</td><td>distance along the curve at which to sample position. This distance should be between zero and <a class="el" href="classOGRLineString.html#22d28cc8ac3526c4a993957a57b75ce9">get_Length()</a> for this curve. </td></tr>
    <tr><td valign="top"></td><td valign="top"><em>poPoint</em>&nbsp;</td><td>the point to be assigned the curve position. </td></tr>
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Implements <a class="el" href="classOGRCurve.html#c96e6d31c407cddc03cc1af9b99e486e">OGRCurve</a>.
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<a class="anchor" name="d2f41c1c69feaea512d561cf16a0e4a3"></a><!-- doxytag: member="OGRLineString::getNumPoints" ref="d2f41c1c69feaea512d561cf16a0e4a3" args="() const" -->
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Fetch vertex count.<p>
Returns the number of vertices in the line string.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>vertex count. </dd></dl>

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<a class="anchor" name="ab63760022e49a795477f2fd31da059f"></a><!-- doxytag: member="OGRLineString::getPoint" ref="ab63760022e49a795477f2fd31da059f" args="(int, OGRPoint *) const " -->
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          <td class="memname">void OGRLineString::getPoint           </td>
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          <td class="paramtype"><a class="el" href="classOGRPoint.html">OGRPoint</a> *&nbsp;</td>
          <td class="paramname"> <em>poPoint</em></td><td>&nbsp;</td>
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Fetch a point in line string.<p>
This method relates to the SFCOM ILineString::get_Point() method.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"></td><td valign="top"><em>i</em>&nbsp;</td><td>the vertex to fetch, from 0 to <a class="el" href="classOGRLineString.html#d2f41c1c69feaea512d561cf16a0e4a3">getNumPoints()</a>-1. </td></tr>
    <tr><td valign="top"></td><td valign="top"><em>poPoint</em>&nbsp;</td><td>a point to initialize with the fetched point. </td></tr>
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<a class="anchor" name="a4c8c1c903bca56f64bc5856f42b2e5c"></a><!-- doxytag: member="OGRLineString::getX" ref="a4c8c1c903bca56f64bc5856f42b2e5c" args="(int i) const " -->
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Get X at vertex.<p>