updated help

Author: marpet

idepix-aatsr/src/main/javahelp/org/esa/snap/idepix/aatsr/docs/aatsr/AatsrAlgo.html

@@ -35,6 +35,12 @@
 </table>
 
 <h3>Algorithm Description</h3>
+<p>The cloud shadow algorithm is based on geometrical considerations alone. With the cloud top height and the
+    illumination direction the shadow position can be determined. As elevated objects are mapped in their apparent
+    position on the ground if not viewed directly from nadir, the sun and observation angles have to be transformed
+    accordingly. In that way, the algorithm translates the question of shadows from spherical geometry of the Earth
+    observation and geo-positions into the space of the regular projection grid.</p>
+
 <h4>North Direction</h4>
 <p>As all calculations of the shadow are translated to the geometry of the pixel grid, it is necessary to calculate the
     north direction (also called orientation or bearing) for each pixel individually.
@@ -120,9 +126,12 @@ <h4>Determining the search path in illumination direction</h4>
 
 <h3>Algorithmic Limitations</h3>
 <h4>Cloud Top Height</h4>
-<p>The AATSR Level-1 product does not provide clooud top height information. Therefor this values is predefined to a
+<p>The AATSR Level-1 product does not provide cloud top height information. Therefor this values is predefined to a
     value of 6000 meter. The processor interface allows to adjust this value for each processed scene.</p>
 
+<h4>Limited to Land</h4>
+<p>The detection of cloud shadow is limited to pixels marked as land. Above water no shadow detection is performed.</p>
+
 <h4>Limited to Daytime</h4>
 <p>The cloud shadow calculation is limited to the daytime. As daytime is the part of the orgbit considered where SZA<85°
     and the confidence_in flag day (bit value 10) is raised.</p>

idepix-aatsr/src/main/javahelp/org/esa/snap/idepix/aatsr/docs/aatsr/AatsrIntro.html

@@ -38,13 +38,16 @@ <h3>Overview</h3>
 
 <p>The nadir product of AATSR 4th reprocessing is missing a flag indicating cloud shadows. The IdePix AATSR Cloud Shadow
     processor aims to provide such a flag over land.
-    It has been the goal to calculate this cloud shadow flag based on the information in the Level 1 product only. From the
+    It has been the goal to calculate this cloud shadow flag based on the information in the Level-1 product only. From
+    the
     cloud flag and the geometry of sun illumination and observation almost all necessary information is given, which
-    allows a translation of the cloud shadow algorithm for OLCI to AATSR.
-    The general idea is to start from a pixel, which has been flagged as a cloud, and follow the direction of
-    illumination until the surface is reached.
-<!--TODO-->    <!--ALMOST? Mention CTH here?-->
-    This Idepix processor does not provide all flags which are defined by other IdePix processors. This one sets only 3 of the general IdePix flags.<br>
+    allows a translation of the cloud shadow algorithm for OLCI to AATSR. The information which is missing in the
+    Level-1 product, is the cloud top height value. Thus this value can be provided as a parameter which is then used
+    for the whole scene.
+    The general idea of the shadow detection algorithm is to start from a pixel, which has been flagged as a cloud, and
+    follow the direction of illumination until the surface is reached.
+    This Idepix processor does not provide all flags which are defined by other IdePix processors. This one sets only
+    3 of the general IdePix flags.<br>
     These are:<br>
     <b>IDEPIX_CLOUD, IDEPIX_CLOUD_SHADOW and IDEPIX_LAND</b>
 </p>
@@ -53,7 +56,8 @@ <h3>Overview</h3>
 <ul>
     <li><a href="AatsrAlgo.html">Description of the Algorithm</a></li>
     <li><a href="AatsrIntro.html">Description of the Processor</a></li>
-    <li><a href="nbdocs://org.esa.snap.snap.help/org/esa/snap/idepix/core/docs/core/IdepixTool.html">Description of IdePix in General</a></li>
+    <li><a href="nbdocs://org.esa.snap.snap.help/org/esa/snap/idepix/core/docs/core/IdepixTool.html">Description of
+        IdePix in General</a></li>
 </ul>
 <br>