INSTRUCTIONS

Creating and Accessing Data for Display

Precipitation totals to be displayed are written into files by chosing the Java display option in the access routine GETHPD.  Filenames thus created are automatically added to a listing file (javafiles.lst ) whose contents are dsiplayed in a box on the upper left of the JAVA display.  Filenames consist of the beginning date of the summation period of the data (in the format YYYYMMDD), then the automatic extension HPD followed by either LST (local standard time) or UTC (Universal time) and the extension PLT.  If alternative filenames are desired, they can be edited into the listing file.
Although datafiles created after the the display routine is started will not be automatically included on the display menu, editing them directly into the list file and clicking on the ÔRefresh listÕ option will bring them onto the menu. When the desired filename appears on the menu, clicking on it and then clicking the ÔLoad DataÕ button will load and then display data in that file Depending on the speed of your browser, loading can take several minutes for large files.  The progress of the loading procedures can be monitored by referring to the status box below the color bar.  On some browsers it is necessary to scroll to the bottom of this box to see the most recent entry. Selecting a new datafile and loading it will automatically supercede the previous data while leaving all options

A description of the data files themselves can be found in the documentation accompanying this software disk.

Displaying data and station information

Precipitation totals (inches) are plotted at HPD stations location as colored squares coded according to the color bar beneathe the display.  Small gray squares indicate operating stations reporting zero rainfall during the period  Open squares indicate at least one unavailable hourly report. It is possible to display data within selectible increments by clicking with the left mouse botton on an individual increment (color) on the color bar or by clicking, holding, and dragging the cursor over a range of increments.  All other colors will be Xed out on the color bar and will not appear on the map. Clicking on any non-Xed-out color on the color bar will restore all observations.   Increments along the color bar can vary from plot to plot depending on the duration of the requested summation  (changes occur at one day and one week).

This display applet cannot plot HPD stations in Alaska, Hawaii, or other United States teritories outside the continental 48 states..

Positioning the cursor at station locations displays station information (identification number and  geographic description) and precipitation amount near the site and in the corresponding boxes above the map.  Latitude and longitude are continuously displayed above the map as the cursor is moved across the map.  Clicking on ÔValuesÕ will display precipitation amount at each station.  Clicking on the option boxes for ÔRiversÕ or ÔCountiesÕ will display rivers and county boundaries.
Clicking on ÔGridsÕ displays latitude and longitude grid lines at one-degree intervals.  To change the default grid intervals, click on ÔGridsÕ with the middle mouse button and set the desired intervals in the box which appears.

 Changiing  the display scale (Zooming)

It is possible to zoom the display to see greater detail or to separate overwritten or crowded observations. This is done by locating the cursor at a corner of the desired zoomed area and dragging the cursor (holding the button down while moving the mouse) until the desired zoom box is produced. The ÔUn-zoomÕ button returns the display to the immediately previous setting. If, after a series of zooms, it is desired to return directly to a full national display, click on the ÔResetÕ button.

 
The size and location of the zoom box can also be changed in another way.  In the overview box which appears when the ÔOverviewÕ button is pressed, the present location of the display is outlined. This option is useful if after several zooms the location of the box is not clear.  Clicking and dragging when the cursor is within the zoom box will move the box while retaining its present shape; clicking and dragging  when the cursor is located on an edge of the box will change the box size.   The overview window can be closed by clicking again on the overview button.

Time Series at Individual Stations

Clicking the mouse when the cursor is located on an individual station will open a new window containing a more detailed bar-graph time series of reports from that station during the accumulation period.  The time increment will be hourly, daily, or monthly, determined by selection when the data is accessed by the routine GETHPD. Including with the time series are station information (name, description, numerical ID, latitude and longitude), accumulated precipitation during the period displayed, and information about data irregularities during the period.  Missing data are indicated by a yellow line beneathe the plot and deleted data by a green line.   Moving the cursor across the time series plot will display the individual amounts and status indicators ( D, M, and A for deleted, missing, and accumulating); clicking above an individual time increment, or holding, dragging across a sub-interval, and releasing, will bring up a new window showing the acumulated precipitation and information about data gaps (if any) during the sub-interval.  All time series windows can be closed simultaneously by clicking on the ÒClose TSÓ button above the plot.