lat1  yes   northernmost latitude bound in decimal degrees or degrees minutes seconds: 90.0 to 90.0 
lat2  yes   southernmost latitude bound in decimal degrees or degrees minutes seconds: 90.0 to 90.0 
latStepSize   1.0  size of steps through latitude interval in degrees 
lon1  yes   westernmost longitude bound in decimal degrees or degrees minutes seconds: 180.0 to 180.0 
lon2  yes   easternmost longitude bound in decimal degrees or degrees minutes seconds: 180.0 to 180.0 
lonStepSize   1.0  size of steps through longitude interval in degrees 
elevation   0.0  elevation of the location: > 10 km 
elevationUnits   K  units of elevation parameter: 'K', 'M', or 'F' 
coordinateSystem   M  'D' (GPS) or 'M' (Mean Sea Level) 
magneticComponent  yes   magnetic component to include in result grid, one of:
d = Declination
i = Inclination
x = North component
y = East component
z = Vertical intensity
h = Horizontal intensity
f = Total intensity

model   WMM  which magnetic reference model to use: 'WMM' or 'IGRF' 
startYear   current year  start year of calculation interval: WMM:20142019, IGRF:15902014 
startMonth   current month  start month of calculation interval: 1  12 
startDay   current day  start day of calculation interval: 1  31 
endYear   current year  end year of calculation interval: WMM:20142019, IGRF:15902014 
endMonth   current month  end month of calculation interval: 1  12 
endDay   current day  end day of calculation interval: 1  31 
dateStepSize   1.0  size of steps through calculation interval in decimal years 
resultFormat   xml  format of calculation results: 'xml' or 'csv' 