Merge pull request #643 from adokter/fix_K_eta_dbz_convert

update default K in `eta_to_dbz()` and `dbz_to_eta()`
adokter · Nov 1, 2023 · a517579 · a517579
2 parents b7e919b + 10ada4d
commit a517579
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diff --git a/NEWS.md b/NEWS.md
@@ -1,3 +1,10 @@
+
+# bioRad 0.7.3.9000
+
+** Bugfixes
+
+* Updated the default refractive index value used in conversion of linear reflectivity (eta) to logarithmic reflectivity (dBZ) (#642). The effect is a 7% increase in animal densities in output of functions `integrate_to_ppi()` and `read_cajun()` only.
+
 # bioRad 0.7.3
 
 ## New features

diff --git a/R/dbz_eta.R b/R/dbz_eta.R
@@ -24,7 +24,7 @@
 #' # radar cross section of 11 cm^2 per individual
 #' dbz_to_eta(7, 5) / 11 # C-band
 #' dbz_to_eta(7, 10) / 11 # S-band
-dbz_to_eta <- function(dbz, wavelength, K = 0.93) {
+dbz_to_eta <- function(dbz, wavelength, K = sqrt(0.93)) {
   assertthat::assert_that(is.numeric(dbz))
   assertthat::assert_that(is.numeric(wavelength) & all(wavelength > 0), msg = "`wavelength` must be a strictly positive numeric.")
   assertthat::assert_that(is.numeric(K) & all(K > 0), msg = "`K` must be a strictly positive numeric.")
@@ -53,7 +53,7 @@ dbz_to_eta <- function(dbz, wavelength, K = 0.93) {
 #' # cross section of 11 cm^2 per individual
 #' eta_to_dbz(1000 * 11, 5) # C-band
 #' eta_to_dbz(1000 * 11, 10) # S-band
-eta_to_dbz <- function(eta, wavelength, K = 0.93) {
+eta_to_dbz <- function(eta, wavelength, K = sqrt(0.93)) {
   assertthat::assert_that(is.numeric(eta) & all(eta>=0), msg = "`eta` must be a strictly positive numeric.")
   assertthat::assert_that(is.numeric(wavelength) & all(wavelength > 0), msg = "`wavelength` must be a strictly positive numeric.")
   assertthat::assert_that(is.numeric(K) & all(K > 0), msg = "`K` must be a strictly positive numeric.")

diff --git a/man/dbz_to_eta.Rd b/man/dbz_to_eta.Rd
diff --git a/man/eta_to_dbz.Rd b/man/eta_to_dbz.Rd
diff --git a/tests/testthat/test-dbz_eta.R b/tests/testthat/test-dbz_eta.R
@@ -6,7 +6,7 @@ test_that("dbz_to_eta() returns error on incorrect parameters", {
   })
 
   test_that("dbz_to_eta() returns the correct eta", {
-    expect_equal(dbz_to_eta(7, 5), 2122.439, tolerance = 0.0001)
+    expect_equal(dbz_to_eta(7, 5), 2282.193, tolerance = 0.0001)
   })
 })
 
@@ -19,7 +19,7 @@ test_that("eta_to_dbz() returns error on incorrect parameters", {
   })
 
   test_that("eta_to_dbz() returns the correct dbz", {
-    expect_equal(eta_to_dbz(10000, 10), 25.77285, tolerance = 0.0001)
+    expect_equal(eta_to_dbz(10000, 10), 25.45768, tolerance = 0.0001)
   })
 })
 
diff --git a/tests/testthat/test-read_cajun.R b/tests/testthat/test-read_cajun.R
@@ -64,11 +64,12 @@ test_that("read_cajun() returns expected data", {
   write.csv(x = cajun_csv, non_empty_file_path)
   expect_equal(
     ignore_attr = TRUE,
+    tolerance=0.0001,
     read_cajun(non_empty_file_path, wavelength = c("S"))$data,
     dplyr::tribble(
       ~height, ~u, ~v, ~w, ~ff, ~dd, ~sd_vvp, ~gap, ~dbz, ~eta, ~dens, ~DBZH, ~n, ~n_dbz, ~n_all, ~n_dbz_all, ~elev1, ~nvolumes_gr35_e1, ~elev2, ~nvolumes_gr35_e2, ~vcp, ~percent_rain,
-      1L, 9.1082, 5.4677, NA, 36.8916, 29911L, 7.2845, FALSE, 3.7747820481656, 50L, 4.54545454545455, 0.00727495214460544, NA, -6404.5974442746, NA, 851.2421, 12.5202, 0.3646, 216L, 1.3329, 0L, 852.3826,
-      2L, 14.4428, 10.1568, NA, 44.6877, 49823L, 10.2681, FALSE, 8.54599459536223, 150L, 13.6363636363636, 0.00727495214460544, NA, -241.9400975439, NA, 212.6159, 11.5492, 0.3646, 216L, 1.3329, 0L, 213.7921
+      1L, 9.1082, 5.4677, NA, 36.8916, 29911L, 7.2845, FALSE, 3.459612, 50L, 4.54545454545455, -0.3078956, NA, -6404.5974442746, NA, 851.2421, 12.5202, 0.3646, 216L, 1.3329, 0L, 852.3826,
+      2L, 14.4428, 10.1568, NA, 44.6877, 49823L, 10.2681, FALSE, 8.230824, 150L, 13.6363636363636, -0.3078956, NA, -241.9400975439, NA, 212.6159, 11.5492, 0.3646, 216L, 1.3329, 0L, 213.7921
     )
   )
 })