STATISTICS CROSSTABS                                       STATISTICS CROSSTABS



     THE STATISTICS CROSSTABS command is summarized as follows:

          STATISTICS CROSSTABS is a data description command which produces a
          two-way frequency (crosstabulation) table of the contents of
          two active discrete cell maps.  The table produced is analagous
          to map intersection overlay.  Crosstabulation (contingency table)
          is a joint frequency distribution of cases as defined by the
          categories of two or more variables. STATISTICS CROSSTABS produces
          a report either in the standard statistical package format or in
          an intersection table format.


     The STATISTICS CROSSTABS command is specified as follows:

          STATISTICS (active ID's) CROSSTABS (crosstabs type)


     The individual parameters of the STATISTICS CROSSTABS command are de-
     scribed below:

          (active ID's) are the ID numbers of two discrete cell maps referenced
          in the active map table.

          CROSSTABS is the type of function to be performed.  Three functions
          are available, CROSSTABS, DESCRIBE, and HISTOGRAM.  Since
          CROSSTABS is entered, a two-way frequency table of the contents
          of the two active cell maps will be output.

          (crosstabs type) is the report format, either INTERSECTION or STATPACK.

          INTERSECTION  lists each category of the first map along with the
          area in acres and the percent of the non-background cells contained
          in the category.  The command then lists each category in the second
          map that intersects the category in the first map along with the
          acres of intersection and the percent of the cells in the category
          of the second map that were involved in the intersection.

          STATPACK produces a row and column format table in which the
          subjects of the first map (listed vertically on the left) are
          crosstabulated with the subjects of the second map (listed
          horizontally across the top). Each cell in the table contains
          four values. The first is the frequency count which is the
          number of map cells associated with that subject in map 2 which
          intersect with the respective subject in map 1. The next three
          values represent various percentages of cells involved in the
          intersection.  The first is the frequency count divided by the
          total number of cells on the map. The second is the frequency
          divided by the row total (all cells having this value on the
          first map). The last value is the frequency count divided by
          the column total (total cells on the second map having this
          value). The total row and column counts and row and column
          percent of total are also provided. Chi square with degrees of
          freedom and significance is listed after the table is printed.
          Chi square is used for testing the null hypothesis that there
          is no significant difference between the surfaces and is only
          meaningful for related surfaces such as soil and vegetation.


     The following is an example of use of the STATISTICS CROSSTABS command:

           ENTER COMMAND
          ? STATISTICS
           ENTER ACTIVE MAP I.D.(S) FOR STATISTICS
          ? 1 2
           ENTER STATISTICS TYPE (DESCRIBE,CROSSTABS,HISTOGRAM)
          ? CROSSTABS


     The limitations of the STATISTICS CROSSTABS command are as follows:

          -- Can only use active discrete cell maps.

          -- No more than 32,000 unique intersections.


STATISTICS DESCRIBE                                         STATISTICS DESCRIBE



     The STATISTICS DESCRIBE command is summarized as follows:

          STATISTICS DESCRIBE is a data description command that produces
          summary statistics for any polygon, line, or discrete cell map
          referenced in the active map table.  Specifically, for each
          primary attribute associated with a vector map, the command
          computes minimum area or length, maximum area or length, total
          area or length, range, mean, variance, and  standard deviation.
          For a vector map with multiple attributes that has been SELECTED
          by attribute, or BSEARCHED, the minimum, maximum, total, mean,
          variance, and standard deviation is computed for a integer or
          real attribute field.  For discrete cell maps, the command com-
          putes total number of cells, total number of non-zero cells,
          minimum and maximum cell values, range of cell values, and ave-
          rage cell values with and without zeros.


     The STATISTICS DESCRIBE command is specified as follows:

          STATISTICS (active ID) DESCRIBE


     The individual parameters of the STATISTICS DESCRIBE command are described
     below:

          (active ID) is the ID number of a line, polygon, or discrete cell
          map referenced in the active map table.

          DESCRIBE is the type of function to be performed.  Three functions
          are available, CROSSTABS, DESCRIBE, and HISTOGRAM.  Since DESCRIBE
          is entered, a table of summary statistics for each subject in the
          specified active map is produced.


     The following is an example of use of the STATISTICS DESCRIBE command:

           ENTER COMMAND
          ? STATISTICS
           ENTER ACTIVE MAP I.D.(S) FOR STATISTICS
          ? 1
           ENTER STATISTICS TYPE (DESCRIBE,CROSSTABS,HISTOGRAM)
          ? DESCRIBE


     The limitations of the STATISTICS DESCRIBE command are as follows:

          -- Does not work with line maps.

          -- Number of items within subjects must be greater than 3 for vector
             maps.

          -- Separate tables are produced for each vector map subject thus
             increasing printing time.

          -- Cannot use point maps, character attribute fields, dichotomous
             or continuous cell maps.

          -- Map must be active.


STATISTICS HISTOGRAM                                       STATISTICS HISTOGRAM



     The STATISTICS HISTOGRAM command is summarized as follows:

          STATISTICS HISTOGRAM is a data description command that produces a
          histogram of the frequency distribution of the subjects in any active
          vector, discrete cell or continuous cell map.


     The STATISTICS HISTOGRAM command is specified as follows:
     (* denotes parameters which can only be entered in a prompted mode)

          STATISTICS (active ID) HISTOGRAM (title)* (number of intervals)*
          (minimum x value)* (maximum x value)* (range delimiters)*


     The individual parameters of the STATISTICS HISTOGRAM command are des-
     ribed below:

          (active ID) is the ID number of a vector, discrete cell or
          continuous cell map referenced in the active table.

          HISTOGRAM is the funtion to be performed. Three funtions are
          available, CROSSTABS, DESCRIBE, and HISTOGRAM.  Since HISTOGRAM
          is entered, a histogram of the frequency of the subjects in a
          map is output.

          (title) is the title to be printed over the histogram. A
          default title is shown in parenthesis following the prompt
          and may selected by entering RETURN. To change the title,
          type in the desired text.

          (number of intervals) is an option for cell data. It is used
          to determine the number of bars to be displayed on the histo-
          gram. It is possible to separate the bars by entering a number
          greater than the number of subjects on the map and specifying
          null ranges where spaces are desired.

          (minimum x value) is an option for cell data. It represented
          the lowest value contained on the map which should be included
          in the calculations for the histogram.

          (maximum x value) is an option for cell data. It represented
          the highest value contained on the map which should be included
          in the calculations for the histogram.

          (range delimiters)is an option for cell data. It is used to
          indicate how the values within the specified bounds be divided
          among the bars. For example, a map with 4 values is to be
          plotted with 2 bars. The lower bound is 1 and the upper bound
          is 4. By specifying 3,4, the first 3 values are summed for the
          first bar and the 4th value is the second bar. Another way to
          specify the same thing would be:
                1 to 3,4
          To skip a bar (leaving a blank space) enter a null range.
          (ie 1 to 3, ,4). This uses up one of the intervals specified
          previously.


     The following is an example of use of the STATISTICS HISTOGRAM command
     using a discrete cell map which contains four subjects:


           ENTER COMMAND
          ? STATISTICS
           ENTER ACTIVE MAP I.D.(S) FOR STATISTICS
          ? 1
           ENTER STATISTICS TYPE (DESCRIBE,CROSSTABS,HISTOGRAM)
          ? HISTOGRAM
          ENTER TITLE:
             ( LAND STATUS          WOLF RIDGE         COLORADO  1:24000)
          ?
           NUMBER OF INTERVALS (  4 ) : ?
           ENTER MINIMUM X VALUE (      1.00) :?
           ENTER MAXIMUM X VALUE (      4.00) :?
          ENTER RANGE DELIMITERS ( EX: 2,4 TO 9, ,100 ):
               1,2,3,4
          ?
            HISTOGRAM RUNNING


     The limitations of the STATISTICS HISTOGRAM command are as follows:

          -- Map must be active.

          -- User cannot define the intervals on the axis of the histogram.

          -- Can not produce Histograms for multiple attribute data.
