From 6cc0f6c27c33ee1418a807e0775ab1d850877644 Mon Sep 17 00:00:00 2001
From: Torsten Dreyer <Torsten@t3r.de>
Date: Thu, 23 Feb 2012 20:23:37 +0100
Subject: [PATCH] Environment: use linear interpolation for wind

Interpolation over time for wind used to be an exponential (low-pass)
filter and is now a noise-spike (linear) filter, This should slow
down wharp9 waves.
---
 Environment/environment.xml       |  2 +-
 Environment/interpolator.xml      | 60 +++++++++++--------------------
 Environment/metarinterpolator.xml | 12 +++----
 3 files changed, 28 insertions(+), 46 deletions(-)

diff --git a/Environment/environment.xml b/Environment/environment.xml
index a65419ee9..9b17450e7 100644
--- a/Environment/environment.xml
+++ b/Environment/environment.xml
@@ -330,7 +330,7 @@
 
   <sea>
     <config>
-      <wind-filter-time type="double">60.0</wind-filter-time>
+      <wind-filter-time type="double">0.05</wind-filter-time>
     </config>
   </sea>
 
diff --git a/Environment/interpolator.xml b/Environment/interpolator.xml
index af1503b70..23b702670 100644
--- a/Environment/interpolator.xml
+++ b/Environment/interpolator.xml
@@ -26,9 +26,7 @@
   <filter>
     <name>EnvironmentInterpolator:temperature-sea-level-degc</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>/environment/config/interpolated/temperature-sea-level-degc</input>
     <output>/environment/temperature-sea-level-degc</output>
@@ -39,9 +37,7 @@
   <filter>
     <name>EnvironmentInterpolator:dewpoint-sea-level-degc</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>/environment/config/interpolated/dewpoint-sea-level-degc</input>
     <output>/environment/dewpoint-sea-level-degc</output>
@@ -58,9 +54,7 @@
     <type>noise-spike</type>
     <max-rate-of-change>0.03</max-rate-of-change>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>/environment/config/interpolated/pressure-sea-level-inhg</input>
     <output>/environment/pressure-sea-level-inhg</output>
@@ -69,9 +63,7 @@
   <filter>
     <name>EnvironmentInterpolator:visibility-m</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>
       <condition>
@@ -91,9 +83,7 @@
   <filter>
     <name>EnvironmentInterpolator:wind-from-north</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>
       <condition>
@@ -103,16 +93,14 @@
     </input>
     <input>/environment/config/interpolated/wind-from-north-fps</input>
     <output>/environment/wind-from-north-fps</output>
-    <type>exponential</type>
-    <filter-time>5</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>0.5</max-rate-of-change>
   </filter>
 
   <filter>
     <name>EnvironmentInterpolator:wind-from-east</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>
       <condition>
@@ -122,8 +110,8 @@
     </input>
     <input>/environment/config/interpolated/wind-from-east-fps</input>
     <output>/environment/wind-from-east-fps</output>
-    <type>exponential</type>
-    <filter-time>5</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>0.5</max-rate-of-change>
   </filter>
 
   <filter>
@@ -138,16 +126,14 @@
       </expression>
     </input>
     <output>/environment/wind-from-down-fps</output>
-    <type>exponential</type>
-    <filter-time>0.5</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>2.0</max-rate-of-change>
   </filter>
 
   <filter>
     <name>EnvironmentInterpolator:turbulence-raw-magnitude</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>
       <condition>
@@ -159,16 +145,14 @@
       <property>/environment/config/interpolated/turbulence/magnitude-norm</property>
     </input>
     <output>/environment/turbulence/raw-magnitude-norm</output>
-    <type>exponential</type>
-    <filter-time>1</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>0.2</max-rate-of-change>
   </filter>
 
   <filter>
     <name>EnvironmentInterpolator:turbulence-magnitude</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>
       <expression>
@@ -186,9 +170,7 @@
   <filter>
     <name>EnvironmentInterpolator:turbulence-rate</name>
     <enable>
-      <condition>
-        <property>/environment/config/enabled</property>
-      </condition>
+      <property>/environment/config/enabled</property>
     </enable>
     <input>/environment/config/interpolated/turbulence/rate-hz</input>
     <output>/environment/turbulence/rate-hz</output>
@@ -205,16 +187,16 @@
     <name>EnvironmentInterpolator:wave:wind-from-east-fps</name>
     <input>/environment/config/boundary/entry[0]/wind-from-east-fps</input>
     <output>/environment/sea/surface/wind-from-east-fps</output>
-    <type>exponential</type>
-    <filter-time>/environment/sea/config/wind-filter-time</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>/environment/sea/config/wind-filter-time</max-rate-of-change>
   </filter>
 
   <filter>
     <name>EnvironmentInterpolator:wave:wind-from-north-fps</name>
     <input>/environment/config/boundary/entry[0]/wind-from-north-fps</input>
     <output>/environment/sea/surface/wind-from-north-fps</output>
-    <type>exponential</type>
-    <filter-time>/environment/sea/config/wind-filter-time</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>/environment/sea/config/wind-filter-time</max-rate-of-change>
   </filter>
 
   <!--filter> unused?
diff --git a/Environment/metarinterpolator.xml b/Environment/metarinterpolator.xml
index 5fc5e18b4..7499bd699 100644
--- a/Environment/metarinterpolator.xml
+++ b/Environment/metarinterpolator.xml
@@ -149,8 +149,8 @@
   <!-- interpolate the wind vector's components -->
   <filter>
     <name>MetarController:wind-from-north-fps</name>
-    <type>exponential</type>
-    <filter-time>30</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>1.0</max-rate-of-change>
     <enable>
       <condition>
         <property>/environment/metar/valid</property>
@@ -163,8 +163,8 @@
 
   <filter>
     <name>MetarController:wind-from-east-fps</name>
-    <type>exponential</type>
-    <filter-time>30</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>1.0</max-rate-of-change>
     <enable>
       <condition>
         <property>/environment/metar/valid</property>
@@ -396,8 +396,8 @@
   </filter>
   <filter>
     <name>MetarController:cloud-alpha</name>
-    <type>exponential</type>
-    <filter-time>5</filter-time>
+    <type>noise-spike</type>
+    <max-rate-of-change>0.2</max-rate-of-change>
     <enable>
       <condition>
         <property>/environment/metar/valid</property>