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The USGS Data Grapher is a set of Internet-based tools that allows users to create customized graphs and tables of continuous monitoring data, including water-quality, meteorological, and streamflow data. Each tool or feature performs a particular task.
Time Series. For the one-site program or feature, the Data Grapher plots either a time series or XY graph (where one parameter is plotted against a different parameter) from data available at only one site. The time series plot is the default option. The two-site feature plots one parameter from each of two sites as either a time series plot or XY graph. For example, one parameter from one site may be plotted on the X-axis while the same parameter from another site would be plotted on the Y-axis. The three-site feature plots a parameter of your choice from three different sites as a time-series graph. "By year or month" plots time-series data from multiple years on a single date axis labeled as either day of year or a particular month. The multiple graphs feature plots graphs for multiple parameters for a specific time period. For example, you can plot turbidity, temperature, and pH for October 2006 without having to redo the one site tool three separate times for three different parameters. The last option under this menu is Color Maps. Color maps are unique plots that use color gradients to help users visualize the plotted data as a function of time of day or day of year.
XY graphs. XY graphs are separated into three different tools. Specialized plots an XY graph but with the option of highlighting specific time periods. Simple is identical to the XY feature from the time series tool, where one parameter is plotted on the X-axis and another parameter is plotted on the Y-axis for one site. Similarly, two site allows for the comparison of parameters from two sites plotted as an XY graph.
Polar graphs. Polar graphs are available for sites with measured wind speed and wind direction data. Unlike the time series or XY graphs that plot along a square grid, polar graphs plot in a circular pattern away from a central origin. Wind rose. A wind rose diagram is very similar to a circular bar graph. The direction vector plots using the 360 degree compass direction, where 0 or 360 degrees is north, 90 degrees is east, 180 degrees is south, and 270 degrees is west. The height of the bars represents a frequency histogram. Speed/direction. For the speed/direction tool, the length of the direction vector, or distance from center, represents the magnitude of the wind speed. Direction is the direction.
Tables. Data tables. Data tables allows users to construct customized tables of any available data in the Data Grapher system. Monthly inventory and daily inventory are table features that offer easy visualization of when data are available for a particular site.
Help. The last feature along the navigation bar is the help menu. The help menu offers user tutorials, such as this, as well as examples of plots that demonstrate how USGS water-quality data can be used.
Many thanks to Steven Sobieszczyk for his expertise and assistance in creating this tutorial!
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