classgdalrasterband.html

gdal库的学习文档

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class&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classGDALRasterBand.html#bb1d0da7bd7239f0d00427b9503c9c3d">GDALRasterBlock</a></td></tr>

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<hr><a name="_details"></a><h2>Detailed Description</h2>
A single raster band (or channel). 
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<hr><h2>Constructor &amp; Destructor Documentation</h2>
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Constructor. Applications should never create GDALRasterBands directly. 
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          <td class="memname">GDALRasterBand::~GDALRasterBand           </td>
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          <td width="100%"><code> [virtual]</code></td>
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Destructor. Applications should never destroy GDALRasterBands directly, instead destroy the <a class="el" href="classGDALDataset.html">GDALDataset</a>. 
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<hr><h2>Member Function Documentation</h2>
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          <td class="memname"><a class="el" href="classGDALRasterBlock.html">GDALRasterBlock</a> * GDALRasterBand::TryGetLockedBlockRef           </td>
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Try fetching block ref.<p>
This method will returned the requested block (locked) if it is already in the block cache for the layer. If not, NULL is returned.<p>
If a non-NULL value is returned, then a lock for the block will have been acquired on behalf of the caller. It is absolutely imperative that the caller release this lock (with GDALRasterBlock::DropLock()) or else severe problems may result.<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>nBlockXOff</em>&nbsp;</td><td>the horizontal block offset, with zero indicating the left most block, 1 the next block and so forth.</td></tr>
    <tr><td valign="top"></td><td valign="top"><em>nYBlockOff</em>&nbsp;</td><td>the vertical block offset, with zero indicating the top most block, 1 the next block and so forth.</td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>NULL if block not available, or locked block pointer. </dd></dl>

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Fetch XSize of raster.<p>
This method is the same as the C function <a class="el" href="gdal_8h.html#25c74f44562ceb26b2efe2f1f28f9b5f">GDALGetRasterBandXSize()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the width in pixels of this band. </dd></dl>

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Fetch YSize of raster.<p>
This method is the same as the C function <a class="el" href="gdal_8h.html#73b9be134e720404e06942dac6f4006e">GDALGetRasterBandYSize()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the height in pixels of this band. </dd></dl>

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Fetch the band number.<p>
This method returns the band that this <a class="el" href="classGDALRasterBand.html">GDALRasterBand</a> objects represents within it's dataset. This method may return a value of 0 to indicate <a class="el" href="classGDALRasterBand.html">GDALRasterBand</a> objects without an apparently relationship to a dataset, such as GDALRasterBands serving as overviews.<p>
This method is the same as the C function <a class="el" href="gdal_8h.html#e446c2b348228220ce16ddadd1216218">GDALGetBandNumber()</a>.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>band number (1+) or 0 if the band number isn't known. </dd></dl>

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<a class="anchor" name="cca217bdbe32f085bdb24e33bf1abb11"></a><!-- doxytag: member="GDALRasterBand::GetDataset" ref="cca217bdbe32f085bdb24e33bf1abb11" args="()" -->
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Fetch the owning dataset handle.<p>
Note that some GDALRasterBands are not considered to be a part of a dataset, such as overviews or other "freestanding" bands.<p>
There is currently no C analog to this method.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the pointer to the <a class="el" href="classGDALDataset.html">GDALDataset</a> to which this band belongs, or NULL if this cannot be determined. </dd></dl>

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          <td class="memname"><a class="el" href="gdal_8h.html#22e22ce0a55036a96f652765793fb7a4">GDALDataType</a> GDALRasterBand::GetRasterDataType           </td>
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Fetch the pixel data type for this band.<p>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>the data type of pixels for this band. </dd></dl>

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