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          <td class="paramtype"><a class="el" href="gdal_8h.html#22e22ce0a55036a96f652765793fb7a4">GDALDataType</a>&nbsp;</td>
          <td class="paramname"> <em>eDT</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nBandCount</em>, </td>
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          <td class="paramtype">int *&nbsp;</td>
          <td class="paramname"> <em>panBandMap</em>, </td>
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          <td class="paramtype">char **&nbsp;</td>
          <td class="paramname"> <em>papszOptions</em></td><td>&nbsp;</td>
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<p>
Advise driver of upcoming read requests.<p>
Some GDAL drivers operate more efficiently if they know in advance what set of upcoming read requests will be made. The <a class="el" href="classGDALDataset.html#03a02a76682d883b378a2241528775c7">AdviseRead()</a> method allows an application to notify the driver of the region and bands of interest, and at what resolution the region will be read.<p>
Many drivers just ignore the <a class="el" href="classGDALDataset.html#03a02a76682d883b378a2241528775c7">AdviseRead()</a> call, but it can dramatically accelerate access via some drivers.<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>nXOff</em>&nbsp;</td><td>The pixel offset to the top left corner of the region of the band to be accessed. This would be zero to start from the left side.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nYOff</em>&nbsp;</td><td>The line offset to the top left corner of the region of the band to be accessed. This would be zero to start from the top.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nXSize</em>&nbsp;</td><td>The width of the region of the band to be accessed in pixels.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nYSize</em>&nbsp;</td><td>The height of the region of the band to be accessed in lines.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBufXSize</em>&nbsp;</td><td>the width of the buffer image into which the desired region is to be read, or from which it is to be written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBufYSize</em>&nbsp;</td><td>the height of the buffer image into which the desired region is to be read, or from which it is to be written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>eBufType</em>&nbsp;</td><td>the type of the pixel values in the pData data buffer. The pixel values will automatically be translated to/from the <a class="el" href="classGDALRasterBand.html">GDALRasterBand</a> data type as needed.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBandCount</em>&nbsp;</td><td>the number of bands being read or written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>panBandMap</em>&nbsp;</td><td>the list of nBandCount band numbers being read/written. Note band numbers are 1 based. This may be NULL to select the first nBandCount bands.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>papszOptions</em>&nbsp;</td><td>a list of name=value strings with special control options. Normally this is NULL.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>CE_Failure if the request is invalid and CE_None if it works or is ignored. </dd></dl>

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<a class="anchor" name="e077c53268d2272eebed10b891a05743"></a><!-- doxytag: member="GDALDataset::RasterIO" ref="e077c53268d2272eebed10b891a05743" args="(GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, int, int, int)" -->
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          <td class="memname">CPLErr GDALDataset::RasterIO           </td>
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          <td class="paramtype"><a class="el" href="gdal_8h.html#e602fdf251b6b0210a5af5a7cf7623b3">GDALRWFlag</a>&nbsp;</td>
          <td class="paramname"> <em>eRWFlag</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nYOff</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nXSize</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nBufYSize</em>, </td>
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          <td class="paramtype"><a class="el" href="gdal_8h.html#22e22ce0a55036a96f652765793fb7a4">GDALDataType</a>&nbsp;</td>
          <td class="paramname"> <em>eBufType</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nBandCount</em>, </td>
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          <td class="paramtype">int *&nbsp;</td>
          <td class="paramname"> <em>panBandMap</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nPixelSpace</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nLineSpace</em>, </td>
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          <td class="paramtype">int&nbsp;</td>
          <td class="paramname"> <em>nBandSpace</em></td><td>&nbsp;</td>
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<p>
Read/write a region of image data from multiple bands.<p>
This method allows reading a region of one or more GDALRasterBands from this dataset into a buffer, or writing data from a buffer into a region of the GDALRasterBands. It automatically takes care of data type translation if the data type (eBufType) of the buffer is different than that of the <a class="el" href="classGDALRasterBand.html">GDALRasterBand</a>. The method also takes care of image decimation / replication if the buffer size (nBufXSize x nBufYSize) is different than the size of the region being accessed (nXSize x nYSize).<p>
The nPixelSpace, nLineSpace and nBandSpace parameters allow reading into or writing from various organization of buffers.<p>
For highest performance full resolution data access, read and write on "block boundaries" as returned by GetBlockSize(), or use the ReadBlock() and WriteBlock() methods.<p>
This method is the same as the C <a class="el" href="gdal_8h.html#764cb93a266ada902b13c2bdad3f7037">GDALDatasetRasterIO()</a> function.<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>eRWFlag</em>&nbsp;</td><td>Either GF_Read to read a region of data, or GF_Write to write a region of data.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nXOff</em>&nbsp;</td><td>The pixel offset to the top left corner of the region of the band to be accessed. This would be zero to start from the left side.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nYOff</em>&nbsp;</td><td>The line offset to the top left corner of the region of the band to be accessed. This would be zero to start from the top.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nXSize</em>&nbsp;</td><td>The width of the region of the band to be accessed in pixels.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nYSize</em>&nbsp;</td><td>The height of the region of the band to be accessed in lines.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>pData</em>&nbsp;</td><td>The buffer into which the data should be read, or from which it should be written. This buffer must contain at least nBufXSize * nBufYSize * nBandCount words of type eBufType. It is organized in left to right,top to bottom pixel order. Spacing is controlled by the nPixelSpace, and nLineSpace parameters.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBufXSize</em>&nbsp;</td><td>the width of the buffer image into which the desired region is to be read, or from which it is to be written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBufYSize</em>&nbsp;</td><td>the height of the buffer image into which the desired region is to be read, or from which it is to be written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>eBufType</em>&nbsp;</td><td>the type of the pixel values in the pData data buffer. The pixel values will automatically be translated to/from the <a class="el" href="classGDALRasterBand.html">GDALRasterBand</a> data type as needed.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBandCount</em>&nbsp;</td><td>the number of bands being read or written.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>panBandMap</em>&nbsp;</td><td>the list of nBandCount band numbers being read/written. Note band numbers are 1 based. This may be NULL to select the first nBandCount bands.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nPixelSpace</em>&nbsp;</td><td>The byte offset from the start of one pixel value in pData to the start of the next pixel value within a scanline. If defaulted (0) the size of the datatype eBufType is used.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nLineSpace</em>&nbsp;</td><td>The byte offset from the start of one scanline in pData to the start of the next. If defaulted the size of the datatype eBufType * nBufXSize is used.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nBandSpace</em>&nbsp;</td><td>the byte offset from the start of one bands data to the start of the next. If defaulted (zero) the value will be nLineSpace * nBufYSize implying band sequential organization of the data buffer.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>CE_Failure if the access fails, otherwise CE_None. </dd></dl>

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<a class="anchor" name="2d135664382507ae0eac0ab1cff07deb"></a><!-- doxytag: member="GDALDataset::Reference" ref="2d135664382507ae0eac0ab1cff07deb" args="()" -->
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          <td class="memname">int GDALDataset::Reference           </td>
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<p>
Add one to dataset reference count.<p>
The reference is one after instantiation.<p>
This method is the same as the C <a class="el" href="gdal_8h.html#c87a46aba65684a3a699de186b01feda">GDALReferenceDataset()</a> function.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the post-increment reference count. </dd></dl>

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<a class="anchor" name="8e820fe1ed71f288e20dd9ef697405c2"></a><!-- doxytag: member="GDALDataset::Dereference" ref="8e820fe1ed71f288e20dd9ef697405c2" args="()" -->
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          <td class="memname">int GDALDataset::Dereference           </td>
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<p>
Subtract one from dataset reference count.<p>
The reference is one after instantiation. Generally when the reference count has dropped to zero the dataset may be safely deleted (closed).<p>
This method is the same as the C <a class="el" href="gdal_8h.html#bbf12b073c2936b45b0ee8031e70b460">GDALDereferenceDataset()</a> function.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the post-decrement reference count. </dd></dl>