PROC KRIGE2D: PROC KRIGE2D Statement :: SAS/STAT(R) 9.2 User's Guide, Second Edition

The KRIGE2D Procedure

PROC KRIGE2D Statement

PROC KRIGE2D options ;

You can specify the following options in the PROC KRIGE2D statement.

DATA=SAS-data-set

specifies a SAS data set containing the $\text{[math]}$ and $\text{[math]}$ coordinate variables and the VAR= variables in the PREDICT statement.

NOPRINT

suppresses the normal display of results. The NOPRINT option is useful when you want only to create one or more output data sets with the procedure. Note that this option temporarily disables the Output Delivery System (ODS); see the section ODS Graphics for more information.

OUTEST=SAS-data-set

OUTE=SAS-data-set

specifies a SAS data set in which to store the kriging predictions, standard errors, and grid location. For details, see the section OUTEST=SAS-data-set.

OUTNBHD=SAS-data-set

OUTN=SAS-data-set

specifies a SAS data set in which to store the neighborhood information for each grid point. Information is written to this data set only if one or more PREDICT statements have options specifying local kriging. For details, see the section OUTNBHD=SAS-data-set.

PLOTS <(global-plot-option)> <= plot-request <(options)>>

PLOTS <(global-plot-option)> <= (plot-request <(options)> <... plot-request <(options)>>)>

controls the plots produced through ODS Graphics. When you specify only one plot request, you can omit the parentheses around the plot request. Here are some examples:

   plots=none
   plots=observ
   plots=(observ(outl) prediction)
   plots=(prediction(fill=pred line=se obs=grad) prediction(fill=se))

You must enable ODS Graphics before requesting plots, for example, like this:

   ods graphics on;
   
   proc krige2d data=thick;
      coordinates xc=East yc=North;
      predict var=thick r=60;
      model scale=7.2881 range=30.6239 form=gauss;
      grid x=0 to 100 by 10 y=0 to 100 by 10;
   run;
   
   ods graphics off;

For general information about ODS Graphics, see Chapter 21, Statistical Graphics Using ODS. If you have enabled ODS Graphics but do not specify the PLOTS= option or have specified PLOTS=ALL, then PROC KRIGE2D produces a default plot for each MODEL statement of every PREDICT statement that you specify. The default PROC KRIGE2D plot displays a contour plot of the kriging prediction and the gradient of the kriging prediction standard error at every location of the prediction grid, as well as empty circles that indicate the observation locations. See Figure 46.4 for an example of the default KRIGE2D plot.

The following global-plot-option is available:



ONLY: suppresses the default plot. Only plots specifically requested are displayed.

The following individual plot-requests and plot options are available:

ALL

produces all appropriate plots. You can specify other options with ALL. For example, to request the default plot and an additional plot of the predictions, specify PLOTS=(ALL PREDICTION).

EQUATE

specifies that all appropriate plots be produced in a way that the axes coordinates have equal size units.

NONE

suppresses all plots.

OBSERVATIONS <(observations-plot-options)>

OBSERV <(observations-plot-options)>

OBS <(observations-plot-options)>

produces the observed data plot. Only one observations plot will be created if you specify the OBSERVATIONS option more than once within a PLOTS option.

The OBSERVATIONS option has the following suboptions:

GRADIENT: specifies that observations be displayed as circles colored by the observed measurement.
OUTLINE: specifies that observations be displayed as circles with a border but with a completely transparent fill.
OUTLINEGRADIENT: is the same as OBSERVATIONS(GRADIENT) except that a border is shown around each observation.
SHOWMISSING: specifies that observations with missing values be displayed in addition to the observations with nonmissing values. By default, missing values locations are not shown on the plot. If you specify multiple instances of the OBSERVATIONS option, and you specify the SHOWMISSING suboption in any of those, then the resulting observations plot will display the observations with missing values.

For the GRADIENT, OUTLINE, and OUTLINEGRADIENT suboptions: The OUTLINEGRADIENT is the default suboption if you do not specify any of those three. If you specify multiple instances of the OBSERVATIONS option or multiple suboptions for OBSERVATIONS, then the resulting observations plot will honor the last specified GRADIENT, OUTLINE, or OUTLINEGRADIENT suboption.

PREDICTION <(prediction-plot-options)>

PRED <(prediction-plot-options)>

specifies that the kriging prediction plot be produced. You can specify the PREDICTION option multiple times in the same PLOTS option to request instances of plots with the following prediction-plot-options:

FILL=NONE | PRED | SE

produces a surface plot for either the predicted values or the standard errors. FILL=SE is the default; however, if you do not specify the FILL suboption the behavior depends on the LINE suboption as follows: If you specify LINE=NONE or do not specify the LINE suboption at all, then the FILL suboption will be set to its default value. If LINE=PRED or LINE=SE, then the FILL suboption will be set to the same value as the LINE suboption.

LINE=NONE | PRED | SE

produces a contour line plot for either the predicted values or the standard errors. LINE=PRED is the default; however, if you do not specify the LINE suboption the behavior depends on the FILL suboption as follows: If you specify FILL=NONE or do not specify the FILL suboption at all, then the LINE suboption will be set to its default value. If FILL=PRED or FILL=SE, then the LINE suboption will be set to the same value as the FILL suboption.

OBS=obs-options

produces an overlaid scatter plot of the observations in addition to the specified contour plots. The following obs-options are available:

GRAD: specifies that observations be displayed as circles colored by the observed measurement. The same color gradient is used to display the prediction surface and the observations. Observations where the prediction is close to the observed values have similar colors—the greater the contrast between the color of an observation and the surface, the larger the prediction standard error is at that point.
LINEGRAD: is the same as OBS=GRAD except that a border is shown around each observation. This option is useful to identify the location of observations where the standard errors are small, because at these points the color of the observations and the color of the surface are indistinguishable.
NONE: specifies that no observations be displayed.
OUTL: specifies that observations be displayed as circles with a border but with a completely transparent fill.

OBS=NONE is the default; however, the default plot in PROC KRIGE2D displays the observations locations as outlines.

If you specify multiple instances of the FILL, LINE, or OBS suboptions in the same PREDICTION option, then the resulting predictions plot will honor the last value specified for any of the suboptions.

Any combination where you specify FILL=NONE and LINE=NONE is not available.

The PREDICTION option requires that predictions be requested at more than one location on a rectangular grid. The plot is not available when you use the GRIDDATA= data set option in the GRID statement, because the GRIDDATA= option allows you to specify any coordinates for the prediction locations.

SINGULARMSG=number

SMSG=number

controls the number of warning messages displayed for a singular matrix. When local kriging is performed, a separate kriging system is solved for each grid point. Anytime a singular matrix is encountered, a warning message is displayed up to a total of SINGULARMSG=n times. The default is SINGULARMSG=10.

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