Creates three-dimensional surface maps in which levels of magnitude
of the specified response variables are represented by spikes of varying height.
Requirements: |
At least one response variable is required and must be numeric.
The ID statement must be used in conjunction with the SURFACE statement.
|
Global statements: |
FOOTNOTE, TITLE
|
The
SURFACE statement specifies the variable or variables that contain the data
that are represented on the map by raised map areas. This statement automatically
determines the midpoints. You can use statement options to control spike
proportions, specify the angle of view, and modify the general appearance
of the map. For example, you can select the color and number of lines for
the representation of the surface area. You can control the selection of
spike heights and base widths.
In addition, you can use global statements to add titles
and footnotes to the map. You can also use an Annotate data set to enhance
the map.
SURFACEresponse-variable(s) </
option(s)>;
|
option(s) can be one or more options from
any or all of the following categories:
-
appearance
options:
| ANNOTATE=Annotate-data-set |
| CBODY=surface-map-color |
| CONSTANT=n |
| NLINES=number-of-lines |
| ROTATE=degrees |
| TILT=degrees |
| XSIZE=map-width
<units> |
| YSIZE=map-height
<units> |
-
description options:
| DESCRIPTION='entry-description' |
| NAME='entry-name' |
- response-variable(s)
- specifies one or more variables in
the response data set that contains response values for map areas in the map
data set. Response-variable must be numeric and must contain
only positive values. Each response variable produces a separate map. All
variables must be in the input data set. Separate multiple response variables
with blanks.
The GMAP procedure scales response variables for presentation
on the map. The height of the spikes on the map correspond to the relative
value of the response variable, not to the actual value of the response variable.
However, when the viewing angle is changed, the spikes may not appear this
way. The spikes in the front may appear to be higher than the spikes in the
back, which represent greater values.
SURFACE statement options affect all
maps that
are produced by that statement.
-
ANNOTATE=Annotate-data-set
ANNO=Annotate-data-set
- specifies a data set to annotate
maps that are produced by the SURFACE statement.
Note: Annotate coordinate systems 1, 2, 7, and 8 are not valid with surface maps.
-
CBODY=surface-map-color
- specifies the color that is used
to draw the surface map. By default, the first color in the current colors
list is used.
-
CONSTANT=n
- specifies a denominator to use in
the distance decay function. This function determines the base width of the
spike that is drawn at each map area center.
By default, CONSTANT=10. Values greater than 10 yield
spikes that are wider at the base. Values less than 10 yield spikes that
are narrower at the base.
Let xk and yk represent the coordinates, and
zk represent the function value at the center of each map
area. The zk values are scaled from 1
to 11. A square grid of x by y points (where the
size of the grid is the NLINES= option value) and the associated function
value f(x,y) are generated from the map area center value using
this formula:
where
and
-
DESCRIPTION='entry-description'
DES='entry-description'
- specifies the description of the
catalog entry for the map. The maximum length for entry-description is 40 characters. The description does not appear on the map. By
default, the GMAP procedure assigns a description of the form SURFACE MAP
OF variable, where variable is the name of the map
variable.
-
NAME='entry-name'
- specifies the name of the catalog
entry for the map. The maximum length for entry-name is eight
characters. The default name is GMAP. If the specified name duplicates the
name of an existing entry, SAS/GRAPH software
adds a number to the duplicate name to create a unique entry, for example,
GMAP1.
-
NLINES=number-of-lines
N=number-of-lines
- specifies the number of lines, n, used to draw the surface map. Values for n are 50 to
100; the higher the value, the more solid the map appears and the more resources
used. By default, NLINES=50.
-
ROTATE=degrees
- specifies the degrees of the angle
at which to rotate the map about the Z axis in the map coordinate system. Degrees can be any angle. Positive values indicate rotation in the
counterclockwise direction. By default, ROTATE=70. The ROTATE= option also
affects the direction of the lines that are used to draw the surface map.
-
TILT=degrees
- specifies the degrees of the angle
at which to tilt the map about the X axis in the map coordinate system. Degrees can be 0 to 90. Increasing values cause the map to tilt backward
and makes the spikes more prominent. Decreasing values make the map shape
more distinguishable and the spikes less prominent. TILT=90 corresponds to
viewing the map edge-on, while TILT=0 corresponds to viewing the map from
directly overhead. By default, TILT=70.
-
XSIZE=map-width <units>
YSIZE=map-height <units>
- specify the physical dimensions of
the map to be drawn, where n is the number of units. By default,
the map uses the entire procedure output area.
Valid units are CM (centimeters), IN (inches),
or PCT (percentage of the graphics output area). By default, the unit is
character cells (CELLS).
If you specify values for map-width and map-height that are greater than the dimensions of the procedure output
area, the map is drawn using the default size. And if you specify only one
dimension, the other is scaled to maintain the aspect ratio.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.