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Adding new srng field to grid and map files + range/CPID filtering with grid_filter #616
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… the slant range of a grid vector
@egthomas, I guess this is designed to work with elevation-based range otherwise I don't see how it will work with the standard or Chisham models with fixed relationship between the group range and distance to the ground projection of the scatter point. Am I correct? |
@pasha-ponomarenko thanks for the question. This new field only stores the slant range (or group path) to the line-of-sight measurement, which can vary depending on radar operating parameters (eg, |
OK, so it just memorises the slant range for each contributing radar which is not stored otherwise, right? So that it enables the user to post-filter the data without re-running the whole gridding/mapping/fitting chain. |
…milar to power and width)
@pasha-ponomarenko yes, exactly! Originally no slant range information was retained once a grid vector was created (note for the TS18 model I modified the code to store the slant range in the grid files' power field, which is not a portable or long-term solution). Here is an example plot using the new |
Hi, I really welcome these changes and it looks great but I am afraid I can't test right now. |
@mtwalach no problem! Even if you are unable to test, any feedback or ideas based on your own extensive work with map files will be greatly appreciated as this pull request is inevitably discussed. |
… meet user-defined slant range criteria
I've just modified the With the
The idea is to eventually support a |
…that do not CPID criteria listed in new cpid.dat file
I've just made one further change to
Obviously these values will need further iteration, so feel free to modify for your own testing purposes. |
This pull request adds a new
srng
field to grid and map files that contains the (average) slant range of the velocity vector recorded by a radar in a given grid cell. All C and IDL read/write routines have been updated to handle files both with and without this new field.Note this is a preliminary step towards more flexible filtering of line-of-sight data based on the measured slant range, which can possibly be contaminated by E-region echoes at near ranges or incorrectly mapped at very far ranges. Ultimately, it should be faster to apply a post-processing range filter on this new
srng
field than using the current-minsrng
and-maxsrng
options withmake_grid
(since those require slant range calculations for all ranges of every input scan).To test, try creating grid and map files with your favorite options and see if anything breaks. The contents of the
srng
field can be viewed with eitherdmapdump -d
or your favorite IDL plotting software (at least until pydarnio is updated).