This compact disc (CD) contains current (water year 1998) and historic water-resources data for Illinois. This CD contains records of stage, discharge, water quality and biology of streams, stage of lakes and reservoirs, water level and water quality of ground-water wells, and precipitation. Data were collected and compiled as a part of the National Water Information System operated by the U.S. Geological Survey in cooperation with Federal, State, and local agencies.
This CD offers more than the traditional printed annual report. The following is a list of new features that are not available from previous reports:
Data are arranged by type, by current year, by previously published data (historic), and by station number or name. The main data types listed in the first selection window when the CD is accessed include: "Surface Water", "Ground Water", "Precipitation", and "Biological." If surface-water data are of interest, for example, "Surface-Water Data" should be selected. Within "Surface-Water Data", other data types can be chosen, such as Stage, Discharge, Partial-Record Sites, or Water Quality. Selecting "Stage" results in the choices: Current Year and Historic Data, as well as, Station Manuscripts. Data contained in "Current Year" include all records published that year. These records also would include previous years' records that are not yet published. Historic stage data consists of mean daily stages previously published that are available from the Illinois District's computer system. Station manuscripts provide descriptive information about each data-collection station, such as station location; period of record; historical extremes outside the period of record; record accuracy; and other remarks pertinent to the station.
Selecting Current Year, Historic Data, or Station Manuscripts within a data type provides a list of stations with data on the CD. Stations are sorted by station number or name. The sort order can be changed by selecting "List by station name" or "List by station number" at the top left of the station table. Near the top right of the table, select "Map" to obtain a map of the stations published this year. Selecting a station on the map will retrieve current-year data when available for that station.
In addition to the station number and name in the station list, there are two other columns; one entitled "Table", the other entitled "RDB" for each station. If "Table" is selected for a station, a Hypertext Markup Language (HTML) document with station manuscript and data table much like the traditional tables previously published in Water Data Reports. An HTML file is a text file that can be read by a browser. If "RDB" is selected, tabular data without a station manuscript will appear. A Relational Data Base (RDB) file consists of tabular data that can be transferred into common software packages for data processing and analysis. Some specifics on HTML data tables and RDB data are mentioned later in this section.
At the bottom of most selection windows is a navigation bar that includes "Introduction", "Surface Water", "Ground Water", "Precipitation", and "Biological". This navigation bar allows quick transfer to other main data types.
The HTML data tables contain a reference to cascading-style sheets, which decrease the font size for printing purposes. When viewing these tables on the screen, however, it may be best to use the default font size for the specific browser by disabling cascading-style sheets. To disable cascading-style sheets on Netscape 4 browser, these instructions should be followed:
To enable the cascading-style sheets, the same instructions should be followed. Cascading-style sheets are used only in recent browsers. Font sizes may have to be adjusted if an older browser is used.
When printing, cascading-style sheets do not contain page breaks. Therefore, data tables may be broken onto multiple pages.
In each line of an RDB-data file, there is a date, a tab, and a data value. The date contains two digits for the month, two for the day, and four for the year. The date March 15, 1999, for example, appears as "03151999".
To save RDB data from most browsers to a computer disk, select <Save As> from
the "File" menu. Then the browser will query where the file will be saved.