Data Plot has access to data from over 4000 traffic detectors. To plot
a graph, you must know the index numbers for the detectors you are interested
in. At this time, there is no online reference; it is recommended that
you obtain a current
All Detector Report
must select at least one detector to get DataPlot to make graphs. This
is done by entering the detector index number at the bottom of the window,
and pressing [Enter]. As many as ten individual detectors
may be plotted at one time, although if more than one detector is selected
then only one date may be plotted.
In addition to plotting individual detectors, Data Plot can also create
detectors. A composite detector is a group of detectors which are averaged
together and plotted as a single line on the graph. To create a composite
detector, just enter two or more detector index numbers, with a space between
is useful for plotting mainline stations with multiple days.
An advanced feature of composite detectors is the ability to include
ramp detectors in the composite. This is done by adding a plus "+" or minus
"-" before a detector index.
This has the effect of adding a ramp volume to the total before computing
the average volume. Ramp detectors have no effect on the occupancy, density,
or speed graphs. Note: all mainline detectors must be specified before
any ramp detectors, because after a "+" or "-", all detectors are treated
as ramp detectors.
least one date must be selected in addition to at least one detector. This
is done using the date selection calendar in the lower left corner of the
window. When the program is first started, the current month will be visible
on the calendar. Each date on the calendar is a toggle button to select
that date for plotting. Dates which do not have data available will be
grayed out and cannot be selected. Up to ten different dates may be plotted
for one detector (or composite detector). If more than one detector has
been selected, then only one date may be selected.
At the top of the date selection calendar, there are four buttons for
selecting the month and year to be displayed. The "<<" and ">>" buttons
select the previous and next years. The "<" and ">" buttons select the
previous and next months.
change the X and Y axis, select the View menu at the top of the window.
One X-axis and up to five Y-axiseses may be plotted on the graph at one
time. Either one may be set to any of Time, Flow, Headway, Occupancy, Density,
or Speed. Time is simply the time of day, ranging from midnight to midnight
of the selected date(s). Flow is the flow rate in vehicles per hour. Headway
is the spacing between vehicles, in seconds. Occupancy is a measurement
of the percent of time a detector is "occupied". Density is displayed as
the number of vehicles per mile. Speed is displayed in miles per hour.
Note: To compute density and speed, each detector must be assigned an
appropriate average field length
. These values are still being
tweaked, so for now, density and speed may not be accurate for all detectors.
For a somewhat more detailed description of this stuff, look
Once an axis has been selected, it is possible to "zoom in" on a smaller
range of that axis. For a vertical axis, this is done by two buttons on
the right side of the window, "+" and "-". The "+" button zooms in to a
smaller range of values on the graph, and the "-" button zooms out to a
larger range of values. Once zoomed in, the scroll bar next to those buttons
may be used to select the actual range for the zoomed in view. There are
also buttons and a scroll bar for controlling the horizontal axis just
below the graph. They work in the same manner.
"smoothing" of the graph is the sampling period of each point plotted on
the graph. Data is collected in 30 second intervals, so the sampling period
must be a multiple of 30 seconds. There are 17 pre-selected sampling periods
which may be chosen. Based on the zoom level of the time axis, only certain
sampling periods are available for selection. Data Plot only makes available
the sampling periods which would plot between 20 and 200 points. This range
was chosen because less than 20 points is uninteresting, and more than
200 points is too much information.
It is possible to see the points themselves, without lines connecting
them. Simply right-click on the graph and de-select the "Connect points"
check box that pops up.
Printing is very simple in Data Plot. First, set up the graph exactly the
way you want it to be printed, and then select the "Print" item from the
"File" menu. The "Page Setup" dialog will come up. Select the paper size,
orientation and margins and press "OK". Now, the print dialog will pop
up. Select the printer and press "OK".
DataPlot is capable of importing and exporting data.
To export data, simply create the graphs you want to export and choose "Export"
from the "File" menu. If you are running DataPlot as a client, you will be prompted
to allow access to your local file system. After granting access, you are
presented with a dialog where you can enter the location and filename you wish to
save the data under. Click save and that's it! DataPlot is not
exporting Composite detectors
To import data, choose "Import" from the "File" menu. Again, a client session
of DataPlot will prompt you for local file system access and after granting
that access, you will be presented with an "Open" dialog. Browse to the proper
location and select the appropriate file. Click "Open" and that's it!
A note about importing and exporting... exporting will overwrite (not append)
Importing requires the file to be in very specific layout. Although the file is simple
ascii text format, it is recommended that you don't edit these files.