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Edit File: blockSize.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Block size for writing files</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for blockSize {raster}"><tr><td>blockSize {raster}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Block size for writing files</h2> <h3>Description</h3> <p>This function can be used to suggest chunk sizes (always a number of entire rows), and corresponding row numbers, to be used when processing Raster* objects in chunks. Normally used together with <code><a href="writeValues.html">writeValues</a></code>. </p> <h3>Usage</h3> <pre> blockSize(x, chunksize, n=nlayers(x), minblocks=4, minrows=1) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>x</code></td> <td> <p>Raster* object</p> </td></tr> <tr valign="top"><td><code>chunksize</code></td> <td> <p>Integer, normally missing. Can be used to set the block size; unit is number of cells. Block size is then computed in units of number of rows (always >= 1) </p> </td></tr> <tr valign="top"><td><code>n</code></td> <td> <p>Integer. number of layers to consider. The function divides chunksize by n to determine blocksize </p> </td></tr> <tr valign="top"><td><code>minblocks</code></td> <td> <p>Integer. Minimum number of blocks </p> </td></tr> <tr valign="top"><td><code>minrows</code></td> <td> <p>Integer. Minimum number of rows in each block </p> </td></tr> </table> <h3>Value</h3> <p>A list with three elements: </p> <p><code>rows</code>, the suggested row numbers at which to start the blocks for reading and writing, </p> <p><code>nrows</code>, the number of rows in each block, and, </p> <p><code>n</code>, the total number of blocks </p> <h3>See Also</h3> <p><code><a href="writeValues.html">writeValues</a></code> </p> <h3>Examples</h3> <pre> r <- raster(system.file("external/test.grd", package="raster")) blockSize(r) </pre> <hr /><div style="text-align: center;">[Package <em>raster</em> version 3.3-13 <a href="00Index.html">Index</a>]</div> </body></html>