From 6d2cdacc2ba4d95ad1d80d6824adb025accfd273 Mon Sep 17 00:00:00 2001
From: Since <ax20yhum@cip.cs.fau.de>
Date: Wed, 20 Dec 2017 13:54:10 +0100
Subject: [PATCH] Correctly process level fields in other runlength based
formats
---
header.go | 23 ++++++++++++++++-------
header_test.go | 6 +++---
radolan.go | 23 ++++++++++++-----------
runlength.go | 13 +++++++++----
4 files changed, 40 insertions(+), 25 deletions(-)
diff --git a/header.go b/header.go
index e4308c9..8206e73 100644
--- a/header.go
+++ b/header.go
@@ -3,7 +3,6 @@ package radolan
import (
"bufio"
"fmt"
- "strings"
"time"
"unicode"
)
@@ -108,15 +107,25 @@ func (c *Composite) parseHeader(reader *bufio.Reader) error {
}
// Parse Level - Example "LV 6 1.0 19.0 28.0 37.0 46.0 55.0"
+ // or "LV12-31.5-24.5-17.5-10.5 -5.5 -1.0 1.0 5.5 10.5 17.5 24.5 31.5"
if lv, ok := section["LV"]; ok {
- level := strings.Fields(lv)
- if len(level) < 2 {
- return newError("parseHeader", "invalid level count")
+ if len(lv) < 2 {
+ return newError("parseHeader", "level field too short")
}
- c.level = make([]DBZ, len(level)-1)
- for i, f := range level[1:] {
- if _, err = fmt.Sscanf(f, "%f", &c.level[i]); err != nil {
+ var cnt int
+ if _, err = fmt.Sscanf(lv[:2], "%d", &cnt); err != nil {
+ return newError("parseHeader", "could not parse level count: "+err.Error())
+ }
+
+ if len(lv) != cnt*5+2 { // fortran format I2 + F5.1
+ return newError("parseHeader", "invalid level format: "+lv)
+ }
+
+ c.level = make([]RVP6, cnt)
+ for i := range c.level {
+ n := i * 5
+ if _, err = fmt.Sscanf(lv[n+2:n+7], "%f", &c.level[i]); err != nil {
return newError("parseHeader", "invalid level value: "+err.Error())
}
}
diff --git a/header_test.go b/header_test.go
index 1dd9575..1529e6a 100644
--- a/header_test.go
+++ b/header_test.go
@@ -21,7 +21,7 @@ type headerTestcase struct {
expDy int
expDataLength int
expPrecision int
- expLevel []DBZ
+ expLevel []RVP6
}
func TestParseHeaderPG(t *testing.T) {
@@ -42,7 +42,7 @@ func TestParseHeaderPG(t *testing.T) {
ht.expDy = 460
ht.expDataLength = 22205 - 159 // BY - header_etx_length
ht.expPrecision = 0
- ht.expLevel = []DBZ{1.0, 19.0, 28.0, 37.0, 46.0, 55.0}
+ ht.expLevel = []RVP6{1.0, 19.0, 28.0, 37.0, 46.0, 55.0}
if err1 != nil || err2 != nil {
t.Errorf("%s.parseHeader(): wrong testcase time.Parse", ht.expProduct)
@@ -71,7 +71,7 @@ func TestParseHeaderFZ(t *testing.T) {
ht.expDy = 450
ht.expDataLength = 405160 - 154 // BY - header_etx_length
ht.expPrecision = -1
- ht.expLevel = []DBZ(nil)
+ ht.expLevel = []RVP6(nil)
if err1 != nil || err2 != nil {
t.Errorf("%s.parseHeader(): wrong testcase time.Parse", ht.expProduct)
diff --git a/radolan.go b/radolan.go
index 068c802..5262b5f 100644
--- a/radolan.go
+++ b/radolan.go
@@ -37,16 +37,17 @@ import (
// raw rvp-6 value (NaN if the no-data flag is set). This rvp-6 value is used differently
// depending on the product type:
//
-// Product label || raw value "live" cloud reflectivity "live" rainfall rate
-// -----------------|| +-------+ +-----+ +------+
-// (PG), FZ, ... || | rvp-6 |---ToDBZ()--->| dBZ |---PrecipitationRate()--->| mm/h |
-// RX, EX || +---+---+ +-----+ +------+
-// -----------------|| - - - | - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-// RW, SF, ... || | +------+
-// || +----- >| mm/h |
-// || | mm/d |
-// -----------------|| +------+
-// aggregated precipitation
+// The rvp-6 value is used differently depending on the product type:
+//
+// Product label | rvp-6 value represents | unit
+// -------------------------+--------------------------+------------------------
+// PG, PC, PX*, ... | cloud reflectivity | dBZ
+// RX, WX, EX, FZ, FX, ... | raw value | convert to dBZ with ToDBZ()
+// RW, SF, ... | aggregated precipitation | mm/h or mm/d
+// PR*, ... | doppler radial velocity | m/s
+//
+// The cloud reflectivity (in dBZ) can be converted to rainfall rate (in mm/h)
+// via PrecipitationRate().
//
// The cloud reflectivity factor Z is stored in its logarithmic representation dBZ:
// dBZ = 10 * log(Z)
@@ -81,7 +82,7 @@ type Composite struct {
dataLength int // length of binary section in bytes
precision int // multiplicator 10^precision for each raw value
- level []DBZ // maps data value to corresponding dBZ value in runlength based formats
+ level []RVP6 // maps data value to corresponding rvp-6 value in runlength based formats
offx float64 // horizontal projection offset
offy float64 // vertical projection offset
diff --git a/runlength.go b/runlength.go
index 451d3fb..6d6e654 100644
--- a/runlength.go
+++ b/runlength.go
@@ -76,11 +76,16 @@ func (c *Composite) decodeRunlength(dst []RVP6, line []byte) error {
return nil
}
-// rvp6Runlength converts the raw value of level based composite products to radar video
-// processor values (rvp-6). NaN may be returned when the given value has no internal mapping.
+// rvp6Runlength sets the value of level based composite products to radar
+// video processor values (rvp-6).
func (c *Composite) rvp6Runlength(value byte) RVP6 {
- if c.level == nil || int(value) >= len(c.level) || value < 0 {
+ if value == 0 {
return RVP6(math.NaN())
}
- return DBZ(c.level[value]).ToRVP6()
+ value--
+
+ if int(value) >= len(c.level) { // border markings
+ return RVP6(math.NaN())
+ }
+ return c.level[value]
}
--
GitLab