pyicon/pyicon_tb.py: Added find_section_indices.

pyicon/pyicon_tb.py

@@ -1954,3 +1954,21 @@ def cons_remap(da, lon=None, lat=None, cell_area=None):
 
     dai = xr.DataArray(dai_ma, coords={'lat': lat_da, 'lon': lon_da})
     return dai
+
+def find_section_indices(clon, clat, lon_sec, lat_sec):
+    # reduce domain to save time
+    ind_reg = np.where(
+        (clon>=lon_sec.min()) & (clon<lon_sec.max()) & (clat>=lat_sec.min()) & (clat<lat_sec.max())
+    )[0]
+    clon_r = clon[ind_reg]
+    clat_r = clat[ind_reg]
+    
+    # get indices
+    dckd_sec_c, ickd_sec_c = calc_ckdtree(lon_i=clon_r.data, lat_i=clat_r.data,
+                                          lon_o=lon_sec, lat_o=lat_sec,
+                                          n_nearest_neighbours=1,
+                                          )
+    inds = np.arange(clon.size, dtype=int)
+    inds_r = inds[ind_reg]
+    inds_sec = inds_r[ickd_sec_c]
+    return inds_sec