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<table width="100%" summary="page for gridded-methods {sp}"><tr><td>gridded-methods {sp}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2> specify spatial data as being gridded, or find out whether they are </h2>

<h3>Description</h3>

<p>returns logical (TRUE or FALSE) telling whether the object is gridded
or not; in assignment promotes a non-gridded structure to a gridded
one, or demotes a gridded structure back to a non-structured one.
</p>

<h3>Usage</h3>

<pre>
	gridded(obj)
	gridded(obj) &lt;- value
	fullgrid(obj)
	fullgrid(obj) &lt;- value
	gridparameters(obj)
</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>obj</code></td>
<td>
<p> object deriving from class &quot;Spatial&quot; (for gridded), or
object of class <a href="SpatialGridDataFrame-class.html">SpatialGridDataFrame-class</a> (for fullgrid and gridparameters)</p>
</td></tr>
<tr valign="top"><td><code>value</code></td>
<td>
<p>logical replacement values, TRUE or FALSE</p>
</td></tr>
</table>

<h3>Value</h3>

<p> if obj derives from class Spatial, gridded(object) will tell
whether it is has topology on a regular grid; if assigned TRUE, if the
object derives from SpatialPoints and has gridded topology,
grid topology will be added to object, and the class of the object
will be promoted to <a href="SpatialGrid-class.html">SpatialGrid-class</a> or 
<a href="SpatialGridDataFrame-class.html">SpatialGridDataFrame-class</a>
</p>
<p><code>fullgrid</code> returns a logical, telling whether the grid is full
and ordered (i.e., in full matrix form), or whether it is not full
or unordered (i.e. a list of points that happen to lie on a grid. If
assigned, the way the points are stored may be changed. Changing a set
of points to full matrix form and back may change the original order of
the points, and will remove duplicate points if they were present.
</p>
<p><code>gridparameters</code> returns, if <code>obj</code> inherits from
SpatialGridDataFrame its grid parameters, else it returns numeric(0).  The
returned value is a data.frame with three columns, named cellcentre.offset
(&quot;lower left cell centre coordinates&quot;), cellsize, and cells.dim (cell
dimension); the rows correspond to the spatial dimensions.
</p>

<h3>Methods</h3>

<dl>
<dt>obj = &quot;Spatial&quot;</dt><dd><p> object deriving from class &quot;Spatial&quot; </p>
</dd>
</dl>

<h3>Examples</h3>

<pre>
# just 9 points on a grid:
x &lt;- c(1,1,1,2,2,2,3,3,3)
y &lt;- c(1,2,3,1,2,3,1,2,3)
xy &lt;- cbind(x,y)
S &lt;- SpatialPoints(xy)
class(S)
plot(S)
gridded(S) &lt;- TRUE
gridded(S)
class(S)
summary(S)
plot(S)
gridded(S) &lt;- FALSE
gridded(S)
class(S)

# data.frame
data(meuse.grid)
coordinates(meuse.grid) &lt;- ~x+y
gridded(meuse.grid) &lt;- TRUE
plot(meuse.grid) # not much good
summary(meuse.grid)

</pre>

<hr /><div style="text-align: center;">[Package <em>sp</em> version 1.4-2 <a href="00Index.html">Index</a>]</div>
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