Brenda and I were talking about this in the meeting earlier, but I did some digging and wanted to put what I found here.
The problem is that our Windcube RHI plots are showing up as offset from 0km on the plot, like this one: https://archive.eol.ucar.edu/docs/isf/projects/lotos2025/iss/realtime/plots/20260303/lidar.ISS2_WLS200S.202603032137.rhi_vel.png
My diagnosis is that this is because the cfradial files have the instrument altitude set (correctly) to 1755m. We didn't see this problem at earlier projects, like M2HATS, where the altitude in PPI files was (incorrectly) set to 0.
I took a brief look into HawkEye/RhiWidget.cc, which looks like it's getting the instrument height from the height above MSL:
void RhiWidget::addBeam(const RadxRay *ray,
const std::vector< std::vector< double > > &beam_data,
const std::vector< DisplayField* > &fields)
{
...
double instHtKm = _manager.getPlatform().getAltitudeKm();
if (instHtKm < -1.0) {
instHtKm = 0.0;
}
RhiBeam* beam = new RhiBeam(_params, ray, instHtKm,
_fields.size(), _startElev, _endElev);That's getting the altitude of the platform above sea level, and then adding that to the beam. For a plot with less wasted space, wouldn't we instead want to be getting height above ground level, i.e.
double instHtKm = _manager.getPlatform().getSensorHtAglM() * 1000;
?
I haven't actually tested this yet, but let me know if you want me to work more on this.
Brenda and I were talking about this in the meeting earlier, but I did some digging and wanted to put what I found here.
The problem is that our Windcube RHI plots are showing up as offset from 0km on the plot, like this one: https://archive.eol.ucar.edu/docs/isf/projects/lotos2025/iss/realtime/plots/20260303/lidar.ISS2_WLS200S.202603032137.rhi_vel.png
My diagnosis is that this is because the cfradial files have the instrument altitude set (correctly) to 1755m. We didn't see this problem at earlier projects, like M2HATS, where the altitude in PPI files was (incorrectly) set to 0.
I took a brief look into HawkEye/RhiWidget.cc, which looks like it's getting the instrument height from the height above MSL:
That's getting the altitude of the platform above sea level, and then adding that to the beam. For a plot with less wasted space, wouldn't we instead want to be getting height above ground level, i.e.
?
I haven't actually tested this yet, but let me know if you want me to work more on this.