Data
The data element in the mugl file specifies
the data to be plotted, either
by listing the data itself in the mugl file, or by describing where
multigraph can find the data. The data element is
the only element that is absolutely required in a
mugl file. (Multigraph can make reasonable default decisions about
everything else, but it has to be given some data to graph!)
There are three ways that you can specify the data. The simplest is to include the data directly in the mugl file, in a list of commma-separated values. The second way is for the mugl file to refer to data that is contained in a separate comma-separated value (csv) file. The third way is for the data to be provided via a web service, in which case the mugl file indicates the address of that service, and multigraph will use the service to fetch the data as needed.
Regardless of which of the above forms the data is in, it is helpful to think of the data as consisting of a table of values, where each column in the table corresponds to a particular variable, and each row corresponds to a set of values for those variables. For example, a data set containing temperature and precipitation values measured every hour for one day might correspond to a table with 3 columns and 24 rows: one column each for the time of measurement, temperature, and precipitation, and one row for each of the 24 hours in the day.
A mugl file's data element should
begin with a variables subelement that indicates
some basic information about the columns in this "table" of data.
The variables
element contains a sequence of variable subelements, each of
which has the following attributes that give information about a data variable:
idAn identifier to be used to refer to this variable elsewhere in the mugl file. The default is "x" for the first variable, "y" for the second variable, and "y1", "y2", ... for any additional variables.
columnA number indicating which "column" the variable is in. The default is 0 for the first variable, 1 for the second, and so on.
typeThe data type of the variable. Should be either 'number' or 'datetime'; the default is 'number'.
After the variables subelement in the
data section, exactly one of the following three subelements should
occur:
valuesThe
valuessubelement should be used when the data is to be included directly in the mugl file. The data should appear between the <values> and </values> tags, with one set of values per line, and individual values on each line separated by commas.csvThe
csvsubelement should be used when the data is in a separate comma-separated values file. Thecsvsubelement has a single attribute namedlocation, whose value should be the name of the csv file.serviceThe
servicesubelement indicates that multigraph should fetch data from a REST web service. It has one attriubute namedlocationwhich should give the address of the web service. Because of JavaScript security restrictions, this address must be on the same server where the HTML page containing the graph is. The value of thelocationattribute should be either a root-relative (i.e., starting with '/') path, or a relative path that is relative to the location of the HTML file. In particular, the REST service URL should not include the "http://" prefix or the server name.