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Introduction
The CRONOS database is an online interface to weather and climate observations collected from automated sensors in North Carolina and surrounding states. The interface uses PHP to communicate with a MySQL database, and is designed to be dynamic and flexible. The target audience of users includes general public as well as advanced users such as researchers.
System Requirements
Web Browser
The CRONOS database requires a web browser. Recommended browsers are Microsoft Internet Explorer version 6 or later, Netscape version 7 or later, or Mozilla version 1.4 or later. Other browsers, such as Mac OSX’s Safari or Opera, have been tested by do not provide all the same functionalities.
Internet Access
Access to the CRONOS database is via the Internet and a web server located in the State Climate Office at NC State University. While high speed Internet access improves access to CRONOS features, it is not required.
Getting Started
Point your web browser to http://www.nc-climate.ncsu.edu/cronos [1]
Your screen should look like the one to the right:
The 3 options on the main CRONOS page are
About the Database – general information about the database, including a link to this users guide. We’ll not cover this section is this guide.
Text list of Stations – List of all stations, color-coded by station type. More details are below.
Interactive Map of Stations – Map of stations. Users can display all active stations in the CRONOS database, as well as current weather conditions, interstates, and rivers and streams. More information is below.
Text List of Stations
By choosing this option, users are presented with a list of all stations in the database with the following information for each station:
NAME
CITY
STATE
COUNTY
TYPE
START DATE
By clicking on any of these column headers, you can sort the list of stations alphabetically by column name. By default, the stations are sorted by STATE and CITY.
Click on the station NAME and users are taken to a page that allows them to select parameters they wish to view. This is covered more in depth below.
Interactive Map of Stations
By clicking on the map image or on the link entitled "Point and Click Weather Map" (on main CRONOS page), you will see a map of North Carolina and the surrounding states. To the left of the map is a menu listing layers that can be turned on or off for the map display. Such layers include county boundaries, interstates, rivers and streams, as well as the various sites within the CRONOS database. A legend that depicts the currently displayed layers is located to the right of the map.
Located above the map are icons that allow you to manipulate what you view. After selecting or de-selecting any layers, you can refresh the map with your new choices by clicking on the "Redraw Map" icon. The "Information" icon displays metadata for the closest site to the point you click on the map. This information will appear above the interactive map. You can also view a list of the next 5 closest stations by clicking on the "show/hide list of nearby stations" link within the metadata information. To begin retrieving data from the chosen station, select the "Get More Data for . . ." link.
Data Retrieval
Once a station has been selected, users are presented with a screen that includes metadata, current conditions, and a list of measurements collected for that station. The list of measurements is station dependent - if the station does not measure a specific parameter, then it will not be listed on the page.
Users can compile hourly data for up to 7 days, and daily observations from ECONet stations for up to 60 days. Daily and monthly options for all stations will be added in the near future.
By checking the box beside a parameter, the user adds that parameter to the list of measurements to view. Users can also select the units they wish to use for many measurements. Once all desired parameters have been checked and units chosen, users should click “RETRIEVE DATA” to view the observations. Users have the option to view data as a web page (default option) or as comma-delimited text.
The web page output shows the observations selected, along with summaries of the data included at the bottom of the table.
In the header of each column, users can click on the GRAPH icon to view a graph of those observations over time. This is an especially useful feature for looking at general trends in the data.
NC CRONOS Database version 2.7.2 [2]