Advanced Plot Options Help

The advanced capabilities that are supported through COHOWeb's Data Explorer form are described below:

Plot Mode:

• Inline Image creates an HTML page as output with an inline GIF image that uses the internal GIF capability of your WWW browser to display GIF images.

• External Image launches the designated GIF viewer specified in your browser's preferences for the image/gif Mime type. Note that the Netscape Navigator sets the default image/gif viewer as inline GIF, so you may want to setup Netscape to use your favorite GIF viewer (such as XV or LView).

• PostScript/Portrait Creates a PostScript file as output in portrait mode. The mime type application/postscript is passed to your browser which may launch a PostScript viewer or prompt to save the file depending on how your browser is configured.

• PostScript/Landscape Creates a PostScript file as output in landscape mode with the same handling as for portrait mode described above.

Paper:

Specify US Letter or A4 to generate a 8.5"x11" or 8.25"x11.75" (210mm x 296mm) PostScript output, which is only applicable when view mode is set to PostScript.

Y-axis scale:

Specify linear or logarithmic scaling of the y-axis, where the default is linear. This option will not change the x-axis scaling for time, which will always be linear.

Character Size:

The overall character size for the annotation. A CHARSIZE of 1.0 is normal. The main title is written with a character size of 1.25 times this parameter.

X-axis style:

Allows specification of X-axis options such as rounding of tick values and selection of a box axis. Each option is listed in the table below:
• Default
• Force exact axis range
• Extend axis range
• Suppress entire axis
• Suppress box style axis

Y-axis style:

Allows specification of Y-axis options such as rounding of tick values and selection of a box axis. Each option is listed in the table below:
• Default
• Force exact axis range
• Extend axis range
• Suppress entire axis
• Suppress box style axis
• Inhibit setting the Y axis minimum value to 0

Plot Symbol:

By default the data points are connected by lines, and no symbols are drawn to mark the points. The following symbols may be chosen:
• Default (no symbol)
• Plus sign (+)
• Asterisk (*)
• Period (.)
• Diamond
• Triangle
• Square
• X
• Histogram mode

In Histogram mode horizontal and vertical lines connect the plotted points, as opposed to the normal method of connecting points with straight lines.

Symbol Size:

Specifies the size (0.1-4.0) of the symbols drawn when plot symbol is selected. The default value of 1.0 produces symbols approximately the same size as a character.

NSUM:

Indicates the number of data points to average when plotting. If the value is larger then 1, every group of NSUM points is averaged to produce one plotted point. If there are m data points, then m/NSUM points are displayed. On logarithmic axes a geometric average is performed.

It is convenient to use when there is an extremely large number of data points because it plots fewer points, the graph is less cluttered, and it is quicker.

Smoothing:

Performs a boxcar smoothing of data prior to the plotting. The size of the boxcar should be an odd number, smaller than the number of data points, and greater than two. If an even number is specified, one plus the given value is used. If the value is less than two then no smoothing is done. Note that the value of the size does not affect the running time to a great extent.

Resolution:

The data is stored as hourly averaged values (24 records per day), which is the default resolution to access. The user may also request daily averaged values to compute the average over every 24-hours of data into a single value. This is useful for trend analysis of large periods of time. Further averaging and smoothing can be done using the above NSUM and SMOOTH options.

Connect Type:

Option to either plot symbols at each point with solid lines connecting the adjoining symbols, or not to connect the points with lines, which applies to all symbols except histogram mode.

Max. Days/Panel:

Specifies the number of days to display in the x-axis of the plots, which is defaulted at 31 days for hourly resolution and 365 days for daily resolution. The plot will be generated up to this number of days and subsequent time periods can be plotted as a new plot by clicking on the "More" button on the control panel when inline GIF images is the selected viewing mode. This option is only applicable to the default inline image plot mode where the output is a HTML page and a "More" button is available to interactively proceed to the next image. However, the other plot modes, namely external image and PostScript, will display data over the entire time period in a single plot.

Color table:

Select the table index (0-40) from among the pre-defined color tables (shown in table below). The default table is 0, which is a standard gray-scale.

 0-        B-W LINEAR  14-             STEPS  28-     Hardcandy
 1-        BLUE/WHITE  15-     STERN SPECIAL  29-        Nature
 2-   GRN-RED-BLU-WHT  16-              Haze  30-         Ocean
 3-   RED TEMPERATURE  17- Blue - Pastel - R  31-    Peppermint
 4- BLUE/GREEN/RED/YE  18-           Pastels  32-        Plasma
 5-      STD GAMMA-II  19- Hue Sat Lightness  33-      Blue-Red
 6-             PRISM  20- Hue Sat Lightness  34-       Rainbow
 7-        RED-PURPLE  21-   Hue Sat Value 1  35-    Blue Waves
 8- GREEN/WHITE LINEA  22-   Hue Sat Value 2  36-       Volcano
 9- GRN/WHT EXPONENTI  23- Purple-Red + Stri  37-         Waves
10-        GREEN-PINK  24-             Beach  38-     Rainbow18
11-          BLUE-RED  25-         Mac Style  39- Rainbow+white
12-          16 LEVEL  26-             Eos A  40- Rainbow+black
13-           RAINBOW  27-             Eos B

Foreground color index:

The color table index (0-255) used to draw the data points, text, and lines. The default index is 0, which is BLACK for the default color table.

Background color index:

The background color index (0-255) to which the screen is initially set before drawing anything. The default index is 191, which is light gray with the default color table.

For example, setting the foreground color to 255 and the background color to 0 creates a WHITE plot on a BLACK background and the reverse creates a BLACK plot on a WHITE background. This option will help when you want to print the page output.

Image size (pixels):

The size of image can be adjusted by setting the width (X-axis) to 300-1024 and the height (Y-axis) to 200-768. The default image size is 640x480 and can be extended to 1024x768 or reduced to 300x200 resolutions. Anything less than 300x200 doesn't produce a readable plot.