Hello all.

I am trying to grind radar observations using wradlib.vpr.CAPPI(). The result I am getting is a 3D array having dimensions 73X101X101 where 73 represents the vertical resolution in Z direction (250 meters till 18000 m and the horizontal resolution is 5000 meters). I want to extract the gridded observations at different heights i.e. 1X101X101, 2x101X101… like that but the confusion is with 101X101 grid points. I am not able to find if the correct x or longitude value is like 101(x/longitude)*101(y/latitude) or 101((y/latitude)*101(x/longitude). Thanks in advance for any help.

Hello @Alok,

the order of the output is [z, y, x] when using wradlib.vpr.CAPPI. You can have a look at this example (you might already have): Recipe #2: Reading and visualizing an ODIM_H5 polar volume — wradlib.

In the last cell there is described how the data is laid out:

```
trgx = trgxyz[:, 0].reshape(trgshape)[0, 0, :]
trgy = trgxyz[:, 1].reshape(trgshape)[0, :, 0]
trgz = trgxyz[:, 2].reshape(trgshape)[:, 0, 0]
```

I’m sorry for the confusion, but this should be made more clear in the documentation.

HTH,

Kai

Thank you for help. Actually I am exporting the gridded data from python to matlab as matfiles. I read on the website that the function *class* wradlib.vpr.CAPPI returns a one dimensional array of the same length as `gridcoords`

(num voxels, ) but in the recipie example the final array is reshaped. Will it be fine if we do not reshape the array and just take the one dimensional values as it is? Will those values correspond to the x,y,z coordinates of the finall cappi data?

Hello @Alok,

yes you can just take the 1D array `(N,)`

from the output without reshaping. It corresponds to the `gridcoords`

(second argument to `CAPPI`

, `(N, 3,)`

).

HTH,

Kai

Thank you sir for help. I am very grateful