Index: palm/trunk/DOC/app/chapter_4.3.html
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--- palm/trunk/DOC/app/chapter_4.3.html (revision 89)
+++ palm/trunk/DOC/app/chapter_4.3.html (revision 217)
@@ -55,5 +55,11 @@
(1) to region (9)), the total domain has the index
0 (region
-(0)).
+(0)). topography_grid_ convention | C*11 | default depends on value of topography; see text for details | Convention for defining the topography grid.
Possible values are
- 'cell_edge': the distance between cell edges defines the extent of topography. This setting is normally for generic topographies, i.e. topographies that are constructed using length parameters. For example, topography = 'single_building' is constructed using building_length_x and building_length_y. 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 dx and dy. This is convenient for resolution parameter studies.
- 'cell_center': the number of topography cells define the extent of topography. This setting is normally for rastered real topographies derived from digital elevation models. For example, topography = 'read_from_file' is constructed using the input file TOPOGRAPHY_DATA. The
+advantage of this setting is that the rastered topography cells of
+the input file are directly mapped to topography grid boxes in PALM.
The example files for sgl_bldg_cell_center and
+sgl_bldg_cell_edge in trunk/EXAMPLES/
+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 'cell_center' convention, the latter applies a generic topography with 'cell_edge' convention.
The default value is
- 'cell_edge' if topography = 'single_building',
- 'cell_center' if topography = 'read_from_file',
- none (' ' ) otherwise, leading to an abort if topography_grid_convention is not set.
This means that
- For PALM simulations using a user-defined topography, the topography_grid_convention must be explicitly set to either 'cell_edge' or 'cell_center'.
- For PALM simulations using a standard topography ('single_building' or 'read_from_file'), it is possible but not required to set the topography_grid_convention because appropriate default values apply
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