classgdaldataset.html

gdal库的学习文档

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          <td class="memname">int GDALDataset::GetRasterCount           </td>
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Fetch the number of raster bands on this dataset.<p>
Same as the C function <a class="el" href="gdal_8h.html#1b9f888aac1cb4dbc99dc1dc023174b7">GDALGetRasterCount()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the number of raster bands. </dd></dl>

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<a class="anchor" name="d96adcf07f2979ad176e37a7f8638fb6"></a><!-- doxytag: member="GDALDataset::GetRasterBand" ref="d96adcf07f2979ad176e37a7f8638fb6" args="(int)" -->
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          <td class="memname"><a class="el" href="classGDALRasterBand.html">GDALRasterBand</a> * GDALDataset::GetRasterBand           </td>
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          <td class="paramtype">int&nbsp;</td>
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Fetch a band object for a dataset.<p>
Equivelent of the C function <a class="el" href="gdal_8h.html#2a74e5e34528589303c1521ebfb9c162">GDALGetRasterBand()</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>nBandId</em>&nbsp;</td><td>the index number of the band to fetch, from 1 to <a class="el" href="classGDALDataset.html#01ed7cc3d711651470212dac01af69a0">GetRasterCount()</a>.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>the height in pixels of raster bands in this <a class="el" href="classGDALDataset.html">GDALDataset</a>. </dd></dl>

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<a class="anchor" name="b6421c7ec7068c274a030e22aa6609e1"></a><!-- doxytag: member="GDALDataset::FlushCache" ref="b6421c7ec7068c274a030e22aa6609e1" args="(void)" -->
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          <td class="memname">void GDALDataset::FlushCache           </td>
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Flush all write cached data to disk.<p>
Any raster (or other GDAL) data written via GDAL calls, but buffered internally will be written to disk.<p>
This method is the same as the C function <a class="el" href="gdal_8h.html#68383ad68c98ba0ef6c3a75637f585b9">GDALFlushCache()</a>. 
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<a class="anchor" name="a42537e1062ce254d124b29ff3ebe857"></a><!-- doxytag: member="GDALDataset::GetProjectionRef" ref="a42537e1062ce254d124b29ff3ebe857" args="(void)" -->
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          <td class="memname">const char * GDALDataset::GetProjectionRef           </td>
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Fetch the projection definition string for this dataset.<p>
Same as the C function <a class="el" href="gdal_8h.html#639a11014cf6c4ff30df6f21d5db9da2">GDALGetProjectionRef()</a>.<p>
The returned string defines the projection coordinate system of the image in OpenGIS WKT format. It should be suitable for use with the OGRSpatialReference class.<p>
When a projection definition is not available an empty (but not NULL) string is returned.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>a pointer to an internal projection reference string. It should not be altered, freed or expected to last for long.</dd></dl>
<dl class="see" compact><dt><b>See also:</b></dt><dd><a href="http://www.gdal.org/ogr/osr_tutorial.html">http://www.gdal.org/ogr/osr_tutorial.html</a> </dd></dl>

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<a class="anchor" name="e2d2e231f6d632f8c2b2cf0078a01150"></a><!-- doxytag: member="GDALDataset::SetProjection" ref="e2d2e231f6d632f8c2b2cf0078a01150" args="(const char *)" -->
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Set the projection reference string for this dataset.<p>
The string should be in OGC WKT or PROJ.4 format. An error may occur because of incorrectly specified projection strings, because the dataset is not writable, or because the dataset does not support the indicated projection. Many formats do not support writing projections.<p>
This method is the same as the C <a class="el" href="gdal_8h.html#145f2be5db1ac31a07a9d4389f4ace65">GDALSetProjection()</a> function.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>pszProjection</em>&nbsp;</td><td>projection reference string.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>CE_Failure if an error occurs, otherwise CE_None. </dd></dl>

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<a class="anchor" name="f9593cc241e7d140f5f3c4798a43a668"></a><!-- doxytag: member="GDALDataset::GetGeoTransform" ref="f9593cc241e7d140f5f3c4798a43a668" args="(double *)" -->
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          <td class="memname">CPLErr GDALDataset::GetGeoTransform           </td>
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Fetch the affine transformation coefficients.<p>
Fetches the coefficients for transforming between pixel/line (P,L) raster space, and projection coordinates (Xp,Yp) space.<p>
<div class="fragment"><pre class="fragment">   Xp = padfTransform[0] + P*padfTransform[1] + L*padfTransform[2];
   Yp = padfTransform[3] + P*padfTransform[4] + L*padfTransform[5];
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In a north up image, padfTransform[1] is the pixel width, and padfTransform[5] is the pixel height. The upper left corner of the upper left pixel is at position (padfTransform[0],padfTransform[3]).<p>
The default transform is (0,1,0,0,0,1) and should be returned even when a CE_Failure error is returned, such as for formats that don't support transformation to projection coordinates.<p>
NOTE: <a class="el" href="classGDALDataset.html#f9593cc241e7d140f5f3c4798a43a668">GetGeoTransform()</a> isn't expressive enough to handle the variety of OGC Grid Coverages pixel/line to projection transformation schemes. Eventually this method will be depreciated in favour of a more general scheme.<p>
This method does the same thing as the C <a class="el" href="gdal_8h.html#df94718221d264fc798043e13adf8c8f">GDALGetGeoTransform()</a> function.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>padfTransform</em>&nbsp;</td><td>an existing six double buffer into which the transformation will be placed.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>CE_None on success, or CE_Failure if no transform can be fetched. </dd></dl>

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<a class="anchor" name="0fe0f81d65d84557b5d71ddc024faa02"></a><!-- doxytag: member="GDALDataset::SetGeoTransform" ref="0fe0f81d65d84557b5d71ddc024faa02" args="(double *)" -->
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Set the affine transformation coefficients.<p>
See <a class="el" href="classGDALDataset.html#f9593cc241e7d140f5f3c4798a43a668">GetGeoTransform()</a> for details on the meaning of the padfTransform coefficients.<p>
This method does the same thing as the C <a class="el" href="gdal_8h.html#e93448112c1a7e69f2764c1aa3c6c8b5">GDALSetGeoTransform()</a> function.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"></td><td valign="top"><em>padfTransform</em>&nbsp;</td><td>a six double buffer containing the transformation coefficients to be written with the dataset.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>CE_None on success, or CE_Failure if this transform cannot be written. </dd></dl>

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<a class="anchor" name="5b3704f0992f5170da34d940016fe095"></a><!-- doxytag: member="GDALDataset::AddBand" ref="5b3704f0992f5170da34d940016fe095" args="(GDALDataType eType, char **papszOptions=NULL)" -->
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