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.
element contains a sequence of
variable subelements, each of
which has the following attributes that give information about a data variable:
An 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.
A number indicating which "column" the variable is in.
The default is 0 for the first variable, 1 for the second, and so on.
The data type of the variable. Should be either 'number' or 'datetime'; the
default is 'number'.
variables subelement in the
data section, exactly one of the following three subelements should
values subelement 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
csv subelement should be used when the data is
in a separate comma-separated values file. The
subelement has a single attribute named
whose value should be the name of the csv file.
service subelement indicates that multigraph should
fetch data from a REST web service. It has one attriubute named
location which should give the address of the web service.
server where the HTML page containing the graph is. The value of the
location attribute 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.