{smcl}
{* 29jan2001}{...}
{hline}
help for {hi:spatcorr}{right:(STB-60: sg162)}
{hline}

{title:Spatial correlogram}

{p 8 14} {cmd:spatcorr} {it:varname} {cmd:,}
{cmdab:b:ands}{cmd:(}{it:numlist}{cmd:)}
{cmdab:x:coord}{cmd:(}{it:varname}{cmd:)}
{cmdab:y:coord}{cmd:(}{it:varname}{cmd:)}
[ {cmdab:g:eary} {cmdab:c:umulative} {cmdab:two:tail} {cmdab:gr:aph}
{cmdab:n:eedle}
{cmdab:sav:egraph}{cmd:(}{it:filename} [{cmd:, replace}]{cmd:)} ]


{title:Description}

{p} {cmd:spatcorr} computes and optionally plots Moran's {it:I} or Geary's
{it:c} spatial correlogram based on two or more consecutive or cumulative
distance bands. For each distance band, {cmd:spatcorr} computes and displays
in tabular form the requested statistic, the expected value of the statistic
under the null hypothesis of global spatial independence, the standard
deviation of the statistic, the {it:z}-value, and the corresponding 1-tail or
2-tail {it:p}-value.


{title:Options}

{p 0 4} {cmd:bands(}{it:numlist}{cmd:)} is always required. It specifies the
sequence of lower and upper bounds of the distance bands to be used in the
calculation of the spatial correlogram. For example, if option
{cmd:bands(0 2 4 6)} is specified and option {cmd:cumulative} is not
specified, then the spatial correlogram will be computed on the following
consecutive distance bands: (0-2], (2-4], (4-6]. On the other hand, if option
{cmd: cumulative} is specified, then the spatial correlogram will be computed
on the following cumulative distance bands: (0-2], (0-4], (0-6].

{p 0 4} {cmd:xcoord(}{it:varname}{cmd:)} is always required. It specifies the
name of the variable containing the {it:x}-coordinate of each location object
of analysis.

{p 0 4} {cmd:ycoord(}{it:varname}{cmd:)} is always required. It specifies the
name of the variable containing the {it:y}-coordinate of each location object
of analysis. Both the {it:x}-coordinate and the {it:y}-coordinate must be
expressed in projected units, e.g., meters, kilometers, miles, or arbitrary
digitizing units.

{p 0 4} {cmd:geary} requests that Geary's {it:c} spatial correlogram be
computed and optionally plotted instead of the default Moran's {it:I} spatial
correlogram.

{p 0 4} {cmd:cumulative} requests that cumulative distance bands be used
instead of the default consecutive distance bands.

{p 0 4} {cmd:twotail} requests that 2-tail {it:p}-values be computed and
displayed instead of the default 1-tail {it:p}-values.

{p 0 4} {cmd:graph} requests that the spatial correlogram be plotted.

{p 0 4} {cmd:needle} requests that the spatial correlogram be plotted using
vertical lines from zero (if Moran's {it:I}) or one (if Geary's {it:c}) to the
computed statistics instead of lines that connect the computed statistics.

{p 0 4} {cmd:savegraph(}{it:filename} [{cmd:, replace}]{cmd:)} requests that
the graph be saved in {it:filename}. If {it:filename} exists, an error will occur
unless {cmd:replace} is also specified. {it:filename} must have one of the
following extensions: {hilite:.ps}, {hilite:.eps}, {hilite:.prn}, or
{hilite:.wmf}.


{title:Examples}

{p 8 12}{inp:. spatcorr crime, bands(0(1)5) xcoord(x) ycoord(y)}

{p 8 12}{inp:. spatcorr crime, bands(0(1)5) xcoord(x) ycoord(y) cumulative}

{p 8 12}{inp:. spatcorr crime, bands(0(1)5) xcoord(x) ycoord(y) graph}


{title:Author}

{p 8} Maurizio Pisati {p_end}
{p 8} Department of Sociology and Social Research {p_end}
{p 8} University of Milano Bicocca - Italy {p_end}
{p 8} maurizio.pisati@galactica.it {p_end}


{title:Also see}

{p 0 19}On-line:  help for {help spatwmat}, {help spatgsa}, {help spatlsa},
{help spatdiag}, {help spatreg} if installed
{p_end}