I used the magnetic field calculator from NOAA to determine the magnetic data for my location for two dates one month apart. This is the result of the comparison:
You might decide that changes in the
total intensity are only significant when greater than 5nt. Adding these lines to the config file gives the result you want:
<dcf:location name="totalintensity-tolerance" xpath="//totalintensity"> <dcf:numeric tolerance="5" use="A"> </dcf:numeric></dcf:location>
Per the attribute use=”A”, the result takes the value from the “A” file.
See our web page Numeric Tolerances for a general discussion of this feature including more examples of element tolerances and using XPaths to identify numeric values.
There is a range of samples available on Bitbucket demonstrating various features of XML Data Compare.