classogrfeaturedefn.html

gdal库的学习文档

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          <td class="memname">void OGRFeatureDefn::AddFieldDefn           </td>
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          <td class="paramtype"><a class="el" href="classOGRFieldDefn.html">OGRFieldDefn</a> *&nbsp;</td>
          <td class="paramname"> <em>poNewDefn</em>          </td>
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Add a new field definition.<p>
This method should only be called while there are no <a class="el" href="classOGRFeature.html">OGRFeature</a> objects in existance based on this <a class="el" href="classOGRFeatureDefn.html">OGRFeatureDefn</a>. The <a class="el" href="classOGRFieldDefn.html">OGRFieldDefn</a> passed in is copied, and remains the responsibility of the caller.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#2a798e8d03299403418a7c87862f1acb">OGR_FD_AddFieldDefn()</a>.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>poNewDefn</em>&nbsp;</td><td>the definition of the new field. </td></tr>
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<a class="anchor" name="81a7dc7ed24fe9f2634bf447d1799e84"></a><!-- doxytag: member="OGRFeatureDefn::GetGeomType" ref="81a7dc7ed24fe9f2634bf447d1799e84" args="()" -->
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          <td class="memname">OGRwkbGeometryType OGRFeatureDefn::GetGeomType           </td>
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<p>
Fetch the geometry base type.<p>
Note that some drivers are unable to determine a specific geometry type for a layer, in which case wkbUnknown is returned. A value of wkbNone indicates no geometry is available for the layer at all. Many drivers do not properly mark the geometry type as 25D even if some or all geometries are in fact 25D. A few (broken) drivers return wkbPolygon for layers that also include wkbMultiPolygon.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#dd0b3a6b6062122e4f4316d194d2a1cf">OGR_FD_GetGeomType()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the base type for all geometry related to this definition. </dd></dl>

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<a class="anchor" name="a0f50b39efbba6559a510d7afcfa5efb"></a><!-- doxytag: member="OGRFeatureDefn::SetGeomType" ref="a0f50b39efbba6559a510d7afcfa5efb" args="(OGRwkbGeometryType)" -->
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          <td class="memname">void OGRFeatureDefn::SetGeomType           </td>
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          <td class="paramtype">OGRwkbGeometryType&nbsp;</td>
          <td class="paramname"> <em>eNewType</em>          </td>
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<p>
Assign the base geometry type for this layer.<p>
All geometry objects using this type must be of the defined type or a derived type. The default upon creation is wkbUnknown which allows for any geometry type. The geometry type should generally not be changed after any OGRFeatures have been created against this definition.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#11ca3a84b54ac36c5f68a03821f1fa78">OGR_FD_SetGeomType()</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>eNewType</em>&nbsp;</td><td>the new type to assign. </td></tr>
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<a class="anchor" name="dbe115a21fb8d247f452ba9d7f00a400"></a><!-- doxytag: member="OGRFeatureDefn::Clone" ref="dbe115a21fb8d247f452ba9d7f00a400" args="()" -->
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          <td class="memname"><a class="el" href="classOGRFeatureDefn.html">OGRFeatureDefn</a> * OGRFeatureDefn::Clone           </td>
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<p>
Create a copy of this feature definition.<p>
Creates a deep copy of the feature definition.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the copy. </dd></dl>

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<a class="anchor" name="2c58c6238242dff3d472faf5e3803922"></a><!-- doxytag: member="OGRFeatureDefn::Reference" ref="2c58c6238242dff3d472faf5e3803922" args="()" -->
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          <td class="memname">int OGRFeatureDefn::Reference           </td>
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<p>
Increments the reference count by one.<p>
The reference count is used keep track of the number of <a class="el" href="classOGRFeature.html">OGRFeature</a> objects referencing this definition.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#6763104e7fafcab1b52d9b0f275e19e8">OGR_FD_Reference()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the updated reference count. </dd></dl>

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<a class="anchor" name="87a280dd42634206dfbcfc47b1ecfea4"></a><!-- doxytag: member="OGRFeatureDefn::Dereference" ref="87a280dd42634206dfbcfc47b1ecfea4" args="()" -->
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          <td class="memname">int OGRFeatureDefn::Dereference           </td>
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<p>
Decrements the reference count by one.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#107635936c90c7f4347d7b3f9fb06e6d">OGR_FD_Dereference()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the updated reference count. </dd></dl>

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<a class="anchor" name="f28dd34d8e3ceee1cb1ba6798711b4e1"></a><!-- doxytag: member="OGRFeatureDefn::GetReferenceCount" ref="f28dd34d8e3ceee1cb1ba6798711b4e1" args="()" -->
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          <td class="memname">int OGRFeatureDefn::GetReferenceCount           </td>
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<p>
Fetch current reference count.<p>
This method is the same as the C function <a class="el" href="ogr__api_8h.html#9e4e8867edeaf1a6f98e6ff284835811">OGR_FD_GetReferenceCount()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the current reference count. </dd></dl>

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<a class="anchor" name="75e1424e3ce755d4393f5b42736d13ee"></a><!-- doxytag: member="OGRFeatureDefn::Release" ref="75e1424e3ce755d4393f5b42736d13ee" args="()" -->
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          <td class="memname">void OGRFeatureDefn::Release           </td>
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Drop a reference to this object, and destroy if no longer referenced. 
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<hr>The documentation for this class was generated from the following files:<ul>
<li><a class="el" href="ogr__feature_8h-source.html">ogr_feature.h</a><li>ogrfeaturedefn.cpp</ul>
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