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ARM-DOE / pyart

The Python-ARM Radar Toolkit. A data model driven interactive toolkit for working with weather radar data.
https://arm-doe.github.io/pyart/
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The toa parameter is interpreted differently in the two gridding methods #442

Closed jjhelmus closed 4 months ago

jjhelmus commented 8 years ago

The toa parameter control the height above which gates are excluded from the gridding algorithm. This parameter is interpreted differently by the two gridding routines.

In the 'map_gates_to_grid' the distance of the gate above the radar is added to the offset of the radar from the grid and compared against toa (toa is the height above grid origin).

In 'map_to_grid' the distance of the gates above the radar is compared directly to toa (toa is the height above the radar).

A uniform interpretation of toa should be used in both gridding methods.

gamaanderson commented 8 years ago

So we have three options,

  1. height above origin
  2. height above radar
  3. height above see level

I'm for the third one!

jjhelmus commented 8 years ago

Another option is to remove to toa parameter entirely and have these gates removed by the gate filter. Adding {include/exclude}_{above/below}_{height/altitude} methods to the GateFilter for including/excluding gates based upon their height above the radar or altitude should make possible.

scollis commented 8 years ago

Exactly.. TOA was introduced to speed gridding by rejecting gates that will never have returns in them.. Gatefilter effectively handles this now.

Jonathan J. Helmus wrote:

Another option is to remove to |toa| parameter entirely and have these gates removed by the gate filter. Adding |{include/exclude}{above/below}{height/altitude}| methods to the GateFilter for including/excluding gates based upon their height above the radar or altitude should make possible.

— Reply to this email directly or view it on GitHub https://github.com/ARM-DOE/pyart/issues/442#issuecomment-168730467.