; + ; NAME: ; iug_load_gmag_cotrans ; ; Purpose: Coordinate transformation between HDZ coordinates & GEO coordinates ; ; HDZ is defined as: ; ; H = horizontal field strength, in the plane formed by Z and GEO graphic north ; D = field strength in the Z x X direction in nT ; Z = downward field strength ; ; H should be a projection onto a basis vector pointing north from station in nT ; D should be a projection onto a basis vector perpendicular to H in the horizontal plane. ; ; Total field strength should be sqrt(H^2+D^2+Z^2) not sqrt(H^2+Z^2) ; D must be in nT not degrees ; ; GEO is defined as: ; X = Vector parallel to vector pointing outward at the intersection of the equatorial plane and the 0 degree longitudinal meridean(Greenwich Meridean) ; Y = Z x X ; Z = Vector parallel to orbital Axis of Earth Pointing northward. ; ; Written by: Atsuki Shinbori ; - pro iug_load_gmag_cotrans ; Set the time span of interest timespan,'8-3-8',2,/days ; thm_load_gmag thm_load_gmag,site = 'thl', trange=trange ; Display all variable names tplot_names ; Plot the thg_mag_bmls data tplot,'thg_mag_thl' ; Now get the data out of tplot: get_data,'thg_mag_thl', data=data_hdz time=data_hdz.x ; Geophysical coordinate transformation from hdz to geo hdz2geo,data_hdz.y,data_xyz,latitude=77.48,longitude=290.83 ; Return data to "TPLOT limbo" with new name store_data, 'thg_mag_thl_geo', data={x:time, y:data_xyz},dlimit={constant:0.} ; Plot the thg_mag_bmls and thg_mag_bmls_geo data tlimit,'8-3-8','8-3-9' ; Limitation of one-day plot options, 'thg_mag_thl', labels=['H','D','Z'] , $ ytitle = 'THL-B (Local GEM)', $ ysubtitle = '[nT]' options, 'thg_mag_thl_geo', labels=['X','Y','Z'] , $ ytitle = 'THL-B (Local GEO)', $ ysubtitle = '[nT]' tplot,['thg_mag_thl','thg_mag_thl_geo'] print,'You success the coordinate transformation from HDZ to geo.' end