Changeset 256 for palm/trunk/DOC/app/chapter_4.1.html

Timestamp:

Mar 8, 2009 8:56:27 AM (16 years ago)

Author:

letzel

Message:

• topography_grid_convention moved from userpar to inipar
• documentation and examples updated

File:

• palm/trunk/DOC/app/chapter_4.1.html (modified) (2 diffs)

palm/trunk/DOC/app/chapter_4.1.html

@@ -14355 +14355 @@
  </span><font color="#000000">
 Alternatively, the user may add code to the user interface subroutine <a href="chapter_3.5.1.html#user_init_grid">user_init_grid</a>
-to allow further topography modes. </font>These require to explicitly set the<span style="font-weight: bold;"> </span><a href="chapter_4.3.html#topography_grid_convention">topography_grid_convention</a>&nbsp;to either <span style="font-style: italic;">'cell_edge'</span> or <span style="font-style: italic;">'cell_center'</span>.<br>
+to allow further topography modes. </font>These require to explicitly set the<span style="font-weight: bold;"> </span><a href="#topography_grid_convention">topography_grid_convention</a>&nbsp;to either <span style="font-style: italic;">'cell_edge'</span> or <span style="font-style: italic;">'cell_center'</span>.<br>
 
       <font color="#000000">
@@ -14426 +14426 @@
 
 
- <tr>
+ <tr><td style="vertical-align: top;"><a name="topography_grid_convention"></a><span style="font-weight: bold;">topography_grid_</span><br style="font-weight: bold;"><span style="font-weight: bold;">convention</span></td><td style="vertical-align: top;">C*11</td><td style="vertical-align: top;"><span style="font-style: italic;">default depends on value of <a href="chapter_4.1.html#topography">topography</a>; see text for details</span></td><td>Convention for defining the&nbsp;topography grid.<br><br>Possible values are<br><ul><li><span style="font-style: italic;">'cell_edge':&nbsp;</span>the distance between cell edges defines the extent of topography. This setting is normally for <span style="font-style: italic;">generic topographies</span>, i.e. topographies that are constructed using length parameters. For example, <a href="chapter_4.1.html#topography">topography</a> = <span style="font-style: italic;">'single_building'</span> is constructed using <a href="chapter_4.1.html#building_length_x">building_length_x</a> and <a href="chapter_4.1.html#building_length_y">building_length_y</a>.
+The advantage of this setting is that the actual size of generic
+topography is independent of the grid size, provided that the length
+parameters are an integer multiple of the grid lengths&nbsp;<a href="chapter_4.1.html#dx">dx</a> and&nbsp;<a href="chapter_4.1.html#dy">dy</a>. This is convenient&nbsp;for resolution parameter studies.</li><li><span style="font-style: italic;">'cell_center'</span><span style="font-style: italic;">:&nbsp;</span>the number of topography cells define the extent of topography. This setting is normally for <span style="font-style: italic;">rastered real topographies</span> derived from digital elevation models.&nbsp;For example, <a href="chapter_4.1.html#topography">topography</a> = <span style="font-style: italic;">'read_from_file'</span> is constructed using&nbsp;the input file <a href="chapter_3.4.html#TOPOGRAPHY_DATA">TOPOGRAPHY_DATA</a><font color="#000000">.&nbsp;</font>The
+advantage of this setting is that the&nbsp;rastered topography cells of
+the input file are directly mapped to topography grid boxes in PALM. <span style="font-style: italic;"></span></li></ul>The example files&nbsp;<big><code>example_topo_file</code></big> and&nbsp;<big><code>example_building</code></big> in <big><code>trunk/EXAMPLES/</code></big>
+illustrate the difference between
+both approaches. Both examples simulate a single building and yield the
+same results. The former uses a rastered topography input file with <span style="font-style: italic;">'cell_center'</span> convention, the latter applies a generic topography with <span style="font-style: italic;">'cell_edge'</span> convention.<br><br>The default value is<br><ul><li><span style="font-style: italic;">'cell_edge' </span>if <a href="chapter_4.1.html#topography">topography</a> = <span style="font-style: italic;">'single_building'</span> or <span style="font-style: italic;">'single_street_canyon'</span>,</li><li><span style="font-style: italic;">'cell_center'</span><span style="font-style: italic;"></span> if <a href="chapter_4.1.html#topography">topography</a> = <span style="font-style: italic;">'read_from_file'</span>,</li><li><span style="font-style: italic;">none (' '</span> ) otherwise, leading to an abort if&nbsp;<span style="font-weight: bold;">topography_grid_convention</span> is not set.</li></ul>This means that <br><ul><li>For PALM simulations using a <span style="font-style: italic;">user-defined topography</span>, the<span style="font-weight: bold;"> topography_grid_convention</span> must be explicitly set to either <span style="font-style: italic;">'cell_edge'</span> or <span style="font-style: italic;">'cell_center'</span>.</li><li>For PALM simulations using a <span style="font-style: italic;">standard topography</span> <span style="font-style: italic;">('single_building'</span>, <span style="font-style: italic;">'single_street_canyon'</span> or <span style="font-style: italic;">'read_from_file')</span>, it is possible but not required to set the&nbsp; <span style="font-weight: bold;">topography_grid_convention</span> because appropriate default values apply.</li></ul></td></tr><tr>