The SIM2D Procedure
Syntax: SIM2D Procedure
The following statements are available in the SIM2D procedure:
PROC SIM2D options;
BY variables;
COORDINATES coordinate-variables;
GRID grid-options;
ID variable;
RESTORE store-options;
SIMULATE simulate-options;
MEAN mean-options;
The SIMULATE and MEAN statements are hierarchical; you can specify any number of SIMULATE statements, but you must specify at least one. If you specify a MEAN statement, it refers to the preceding SIMULATE statement. If you omit the MEAN statement, a zero-mean model is simulated.
You must specify a single COORDINATES statement to identify the x and y coordinate variables in the input data set when you perform a conditional simulation. You must also specify a single GRID statement to specify the grid information.
Table 1 outlines the options available in PROC SIM2D classified by function.
Table 1: Options Available in the SIM2D Procedure
| Task | Statement | Option |
|---|---|---|
| Data Set Options | ||
| Specify an input data set | PROC SIM2D | DATA= |
| Specify a grid data set | GRID | GDATA= |
| Specify labels for individual grid points or in 1-D | GRID | LABEL |
| Specify correlation model and parameters | SIMULATE | MDATA= |
| Write simulated values | PROC SIM2D | OUTSIM= |
| Specify plot display and options | PROC SIM2D | PLOTS |
| Specify a quadratic form data set | MEAN | QDATA= |
| Specify plot display and options | PROC SIM2D | PLOTS |
| Declaring the Role of Variables | ||
| Specify variables to define analysis subgroups | BY | |
| Specify a variable with observation labels | ID | |
| Specify the conditioning variable | SIMULATE | VAR= |
| Specify the x and y coordinate variables in the DATA= data set | COORDINATES | XC= YC= |
| Specify the x and y coordinate variables in the GDATA= data set | GRID | XC= YC= |
| Specify the constant coefficient variable in the QDATA= data set | MEAN | CONST= |
| Specify the linear x coefficient variable in the QDATA= data set | MEAN | CX= |
| Specify the linear y coefficient variable in the QDATA= data set | MEAN | CY= |
| Specify the quadratic x coefficient variable in the QDATA= data set | MEAN | CXX= |
| Specify the quadratic y coefficient variable in the QDATA= data set | MEAN | CYY= |
Specify the quadratic  coefficient variable in the QDATA= data set |
MEAN | CXY= |
| Controlling the Simulation | ||
| Specify the number of grid points in one-dimensional cases | GRID | NPTS= |
| Specify the number of realizations | SIMULATE | NUMREAL= |
| Specify the seed value for the random generator | SIMULATE | SEED= |
| Controlling the Mean Quadratic Surface | ||
| Specify the CONST term | MEAN | CONST= |
| Specify the linear x term | MEAN | CX= |
| Specify the linear y term | MEAN | CY= |
| Specify the quadratic x term | MEAN | CXX= |
| Specify the quadratic y term | MEAN | CYY= |
| Specify the quadratic cross term | MEAN | CXY= |
| Controlling the Semivariogram Model | ||
| Specify an angle for an anisotropic model | SIMULATE | ANGLE= |
| Specify nested angles | SIMULATE | ANGLE=( ) |
| Specify a functional form | SIMULATE | FORM= |
| Specify nested functional forms | SIMULATE | FORM=( ) |
| Specify a nugget effect | SIMULATE | NUGGET= |
| Specify a range parameter | SIMULATE | RANGE= |
| Specify nested range parameters | SIMULATE | RANGE=( ) |
| Specify a minor-major axis ratio for an anisotropic model | SIMULATE | RATIO= |
| Specify nested minor-major axis ratios | SIMULATE | RATIO=( ) |
| Specify a scale parameter | SIMULATE | SCALE= |
| Specify nested scale parameters | SIMULATE | SCALE=( ) |
| Specify item store with correlation information | RESTORE | IN= |
| Specify model and parameters from an item store | SIMULATE | STORESELECT |