ogr__api_8h.html

gdal库的学习文档

Get the number of layers in this data source.<p>
This function is the same as the C++ method <a class="el" href="classOGRDataSource.html#031694429394662fd50353c5e2b68692">OGRDataSource::GetLayerCount()</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>hDS</em>&nbsp;</td><td>handle to the data source from which to get the number of layers. </td></tr>
  </table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>layer count. </dd></dl>

</div>
</div><p>
<a class="anchor" name="ea8cc826474b55371b1b4e24a24ba1db"></a><!-- doxytag: member="ogr_api.h::OGR_DS_GetName" ref="ea8cc826474b55371b1b4e24a24ba1db" args="(OGRDataSourceH)" -->
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">const char * OGR_DS_GetName           </td>
          <td>(</td>
          <td class="paramtype">OGRDataSourceH&nbsp;</td>
          <td class="paramname"> <em>hDS</em>          </td>
          <td>&nbsp;)&nbsp;</td>
          <td width="100%"></td>
        </tr>
      </table>
</div>
<div class="memdoc">

<p>
Returns the name of the data source. This string should be sufficient to open the data source if passed to the same <a class="el" href="classOGRSFDriver.html">OGRSFDriver</a> that this data source was opened with, but it need not be exactly the same string that was used to open the data source. Normally this a filename.<p>
This function is the same as the C++ method <a class="el" href="classOGRDataSource.html#682c885a30cbc3a35ed59ed39f316a55">OGRDataSource::GetName()</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>hDS</em>&nbsp;</td><td>handle to the data source to get the name from. </td></tr>
  </table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>pointer to an internal name string which should not be modified or freed by the caller. </dd></dl>

</div>
</div><p>
<a class="anchor" name="fc7b521a05c1207e298a2b9dbf4a1181"></a><!-- doxytag: member="ogr_api.h::OGR_DS_ReleaseResultSet" ref="fc7b521a05c1207e298a2b9dbf4a1181" args="(OGRDataSourceH, OGRLayerH)" -->
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">void OGR_DS_ReleaseResultSet           </td>
          <td>(</td>
          <td class="paramtype">OGRDataSourceH&nbsp;</td>
          <td class="paramname"> <em>hDS</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">OGRLayerH&nbsp;</td>
          <td class="paramname"> <em>hLayer</em></td><td>&nbsp;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td><td width="100%"></td>
        </tr>
      </table>
</div>
<div class="memdoc">

<p>
Release results of <a class="el" href="ogr__api_8h.html#9892ecb0bf61add295bd9decdb13797a">OGR_DS_ExecuteSQL()</a>.<p>
This function should only be used to deallocate OGRLayers resulting from an <a class="el" href="ogr__api_8h.html#9892ecb0bf61add295bd9decdb13797a">OGR_DS_ExecuteSQL()</a> call on the same <a class="el" href="classOGRDataSource.html">OGRDataSource</a>. Failure to deallocate a results set before destroying the <a class="el" href="classOGRDataSource.html">OGRDataSource</a> may cause errors.<p>
This function is the same as the C++ method OGRDataSource::ReleaseResultsSet().<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>hDS</em>&nbsp;</td><td>an handle to the data source on which was executed an SQL query. </td></tr>
    <tr><td valign="top"></td><td valign="top"><em>hLayer</em>&nbsp;</td><td>handle to the result of a previous <a class="el" href="ogr__api_8h.html#9892ecb0bf61add295bd9decdb13797a">OGR_DS_ExecuteSQL()</a> call. </td></tr>
  </table>
</dl>

</div>
</div><p>
<a class="anchor" name="d0fefab726442fa71ab5ef74fe8549a6"></a><!-- doxytag: member="ogr_api.h::OGR_DS_TestCapability" ref="d0fefab726442fa71ab5ef74fe8549a6" args="(OGRDataSourceH, const char *)" -->
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">int OGR_DS_TestCapability           </td>
          <td>(</td>
          <td class="paramtype">OGRDataSourceH&nbsp;</td>
          <td class="paramname"> <em>hDS</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">const char *&nbsp;</td>
          <td class="paramname"> <em>pszCapability</em></td><td>&nbsp;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td><td width="100%"></td>
        </tr>
      </table>
</div>
<div class="memdoc">

<p>
Test if capability is available.<p>
One of the following data source capability names can be passed into this function, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.<p>
<ul>
<li>
<b>ODsCreateLayer</b>: True if this datasource can create new layers. <p>
</li>
</ul>
<p>
The define macro forms of the capability names should be used in preference to the strings themselves to avoid mispelling.<p>
This function is the same as the C++ method <a class="el" href="classOGRDataSource.html#3b7c054c376151e1a1f63861d7239c8b">OGRDataSource::TestCapability()</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>hDS</em>&nbsp;</td><td>handle to the data source against which to test the capability. </td></tr>
    <tr><td valign="top"></td><td valign="top"><em>pszCapability</em>&nbsp;</td><td>the capability to test.</td></tr>
  </table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>TRUE if capability available otherwise FALSE. </dd></dl>

</div>
</div><p>
<a class="anchor" name="90c0adfd518b71571d9ce8d976fab320"></a><!-- doxytag: member="ogr_api.h::OGR_F_Clone" ref="90c0adfd518b71571d9ce8d976fab320" args="(OGRFeatureH)" -->
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">OGRFeatureH OGR_F_Clone           </td>
          <td>(</td>
          <td class="paramtype">OGRFeatureH&nbsp;</td>
          <td class="paramname"> <em>hFeat</em>          </td>
          <td>&nbsp;)&nbsp;</td>
          <td width="100%"></td>
        </tr>
      </table>
</div>
<div class="memdoc">

<p>
Duplicate feature.<p>
The newly created feature is owned by the caller, and will have it's own reference to the <a class="el" href="classOGRFeatureDefn.html">OGRFeatureDefn</a>.<p>
This function is the same as the C++ method <a class="el" href="classOGRFeature.html#580a742ae4952c3a4a0dd25ae2afb7e5">OGRFeature::Clone()</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>hFeat</em>&nbsp;</td><td>handle to the feature to clone. </td></tr>
  </table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>an handle to the new feature, exactly matching this feature. </dd></dl>

</div>
</div><p>
<a class="anchor" name="0d820fd7da6a079048c0d21e26fc9e47"></a><!-- doxytag: member="ogr_api.h::OGR_F_Create" ref="0d820fd7da6a079048c0d21e26fc9e47" args="(OGRFeatureDefnH)" -->
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">OGRFeatureH OGR_F_Create           </td>
          <td>(</td>
          <td class="paramtype">OGRFeatureDefnH&nbsp;</td>
          <td class="paramname"> <em>hDefn</em>          </td>
          <td>&nbsp;)&nbsp;</td>
          <td width="100%"></td>
        </tr>
      </table>
</div>
<div class="memdoc">

<p>
Feature factory.<p>
Note that the <a class="el" href="classOGRFeature.html">OGRFeature</a> will increment the reference count of it's defining <a class="el" href="classOGRFeatureDefn.html">OGRFeatureDefn</a>. Destruction of the <a class="el" href="classOGRFeatureDefn.html">OGRFeatureDefn</a> before destruction of all OGRFeatures that depend on it is likely to result in a crash.<p>
This function is the same as the C++ method <a class="el" href="classOGRFeature.html#e6559a9f3c26274d1253e5d043b2e852">OGRFeature::OGRFeature()</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>hDefn</em>&nbsp;</td><td>handle to the feature class (layer) definition to whic