McIDAS-V Support Forums

Hi,

Is there a way to get the projection scale_factor and add_offset for x and y in the GOES-16 netCDF files using loadGrid?

Thanks,
Joleen

Hi Joleen -

I looked into this a bit and I wasn't seeing any way of getting at this information. I have forwarded this to a few programmers more familiar with VisAD to see if anything there could help. For example, there may be something buried in the VisAD GeoGrid class that I haven't been able to find myself. After speaking with a different programmer, we were curious as to why you need to know these values.

I'll follow up with you when I hear back from the programmers.

Thanks -
Bob Carp

Hi Bob,

I wanted to use a lat/lon, find the fixed grid coordinate, then use a range around that fix grid coordinate for xRange and yRange in loadGrid.

Class GEOSTransform

Code: Select all

FGFtoEarth(double fgf_x, double fgf_y, double scale_x, double offset_x, double scale_y, double offset_y)

Transform fractional FGF coordinates to (longitude, latitude).

Code: Select all

earthToFGF(double geographic_lon, double geographic_lat, double scale_x, double offset_x, double scale_y, double offset_y)

Transform Earth coordinates (lon,lat) to fractional FGF coordinates.

Having a quick formula to find out FGFtoEarth and back could be very useful when selecting data regions in scripting.

In addition, I was having problems selecting the display region using the interactive GUI, the only thing I could do was reduce the mage size by stride, and I did not want to stride the data.

Joleen

Actually, that does not make sense, because the xRange and yRange are row, column indices, not the fixed grid coordinate values.

Pardon my confusion...
Joleen

Thanks for following up, Joleen. Just for clarification, are you no longer needing a way to get at x/y projection scale_factor and add_offset values?

- Bob

At this moment, no, I do not need to access the scale and offset factors for the x,y coordinates.
Joleen