Template:Quadratic Friction: Difference between revisions

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If the landuse type is chosen as NLCD or C-CAP, the default values below are used in the calculation.  If there is a different landuse raster type, or wishing to use values that differ from the defaults, specify the raster type as "Custom" and provide a CSV file with the desired values.
If the landuse type is chosen as NLCD or C-CAP, the default values below are used in the calculation.  If there is a different landuse raster type, or wishing to use values that differ from the defaults, specify the raster type as "Custom" and provide a CSV file with the desired values.
===Directional Roughness NLCD Mapping Table===
===Quadratic Friction NLCD Mapping Table===
{| class="wikitable sortable"
{| class="wikitable sortable"
|+ Directional Roughness NLCD Values
|+ Quadratic Friction NLCD Values
! Code !! Description !! Roughness
! Code !! Description !! Friction
<!--Use this template to add a new entry:
<!--Use this template to add a new entry:
|-
|-
| Code        || Description                              || Roughness                  
| Code        || Description                              || Friction                  
-->
-->
|-
|-
| 0          || Background                              || 0
| 0          || Background                              || 0.002
|-
|-
| 1          || Unclassified                            || 0
| 1          || Unclassified                            || 0.002
|-
|-
| 11          || Open Water                              || 0.001
| 11          || Open Water                              || 0.0018
|-
|-
| 12          || Perennial Ice/Snow                      || 0.012
| 12          || Perennial Ice/Snow                      || 0.00046
|-
|-
| 21          || Developed Open Space                    || 0.1
| 21          || Developed Open Space                    || 0.0018
|-
|-
| 22          || Developed Low Intensity                  || 0.3
| 22          || Developed Low Intensity                  || 0.011
|-
|-
| 23          || Developed Medium Intensity              || 0.4
| 23          || Developed Medium Intensity              || 0.046
|-
|-
| 24          || Developed High Intensity                || 0.55
| 24          || Developed High Intensity                || 0.1
|-
|-
| 31          || Barren Land (Rock/Sand/Clay)            || 0.04
| 31          || Barren Land (Rock/Sand/Clay)            || 0.037
|-
|-
| 41          || Deciduous Forest                        || 0.65
| 41          || Deciduous Forest                        || 0.046
|-
|-
| 42          || Evergreen Forest                        || 0.72
| 42          || Evergreen Forest                        || 0.055
|-
|-
| 43          || Mixed Forest                            || 0.71
| 43          || Mixed Forest                            || 0.046
|-
|-
| 51          || Dwarf Scrub                              || 0.1
| 51          || Dwarf Scrub                              || 0.0073
|-
|-
| 52          || Shrub/Scrub                              || 0.12
| 52          || Shrub/Scrub                              || 0.011
|-
|-
| 71          || Grassland/Herbaceous                    || 0.04
| 71          || Grassland/Herbaceous                    || 0.0053
|-
|-
| 72          || Sedge/Herbaceous                        || 0.03
| 72          || Sedge/Herbaceous                        || 0.0041
|-
|-
| 73          || Lichens                                  || 0.025
| 73          || Lichens                                  || 0.0033
|-
|-
| 74          || Moss                                    || 0.02
| 74          || Moss                                    || 0.0028
|-
|-
| 81          || Pasture/Hay                              || 0.06
| 81          || Pasture/Hay                              || 0.005
|-
|-
| 82          || Cultivated Crops                        || 0.06
| 82          || Cultivated Crops                        || 0.0062
|-
|-
| 90          || Woody Wetlands                          || 0.55
| 90          || Woody Wetlands                          || 0.046
|-
|-
| 95          || Emergent Herbaceous Wetlands            || 0.11
| 95          || Emergent Herbaceous Wetlands            || 0.0092
|-
|-
| 91          || Palustrine Forested Wetland              || 0.55
| 91          || Palustrine Forested Wetland              || 0.046
|-
|-
| 92          || Palustrine Scrub/Shrub Wetland          || 0.12
| 92          || Palustrine Scrub/Shrub Wetland          || 0.01
|-
|-
| 93          || Estuarine Forested Wetland              || 0.55
| 93          || Estuarine Forested Wetland              || 0.046
|-
|-
| 94          || Estuarine Scrub/Shrub Wetland            || 0.12
| 94          || Estuarine Scrub/Shrub Wetland            || 0.01
|-
|-
| 96          || Palustrine Emergent Wetland (Persistent) || 0.11
| 96          || Palustrine Emergent Wetland (Persistent) || 0.0092
|-
|-
| 97          || Estuarine Emergent Wetland              || 0.11
| 97          || Estuarine Emergent Wetland              || 0.0092
|-
|-
| 98          || Palustrine Aquatic Bed                  || 0.03
| 98          || Palustrine Aquatic Bed                  || 0.001
|-
|-
| 99          || Estuarine Aquatic Bed                    || 0.03
| 99          || Estuarine Aquatic Bed                    || 0.001
|}
|}
{{-}}
{{-}}

Revision as of 22:06, 5 August 2021

Quadratic Fiction

The Quadratic Friction tool is used to populate the spatial attributes for the quadratic friction coefficient at the sea floor. A new dataset is created from NLCD, C-CAP, or other landuse rasters.

The tool will extract values from the raster object specified by the tool. For each node in the geometry, the "area of influence" is computed for the node. The area of influence is a polygon that represents the area of the geometry around a node. This is computed as the area encompassing the node and half the distance to each of his neighboring nodes. All of the raster values within the area of influence are extracted from the visible raster objects. A composite quadratic friction value is computed taking a weighted average of all the raster values. If the area of the extracted values is less then the area of influence around the node (because the process passed the extent of the raster objects or encountered null values), the default value is used to compute the quadratic friction using the area not represented in the values.

The Quadratic Friction tool dialog contains the following options:

  • Input landuse raster – This is a required input parameter and should cover the entire target grid. Specify which raster in the project to use when determining the quadtratic friction.
  • Landuse raster type – This is a required parameter. Specify what type of landuse raster to use.
    • "NLCD" – Sets the landuse raster type to National Land Cover Dataset (NLCD). A mapping table file for NLCD can be found here and down below.
    • "C-CAP" – Sets the landuse raster type to Coastal Change Analysis Program (C-CAP). A mapping table file for C-CAP can be found here and down below.
    • "Other" – Sets the landuse raster type to be set by the user. This adds an option to the dialog.
      • Landuse to quadtratic friction mapping table – The Select File... button will allow a table file to be selected. The entire file name will be displayed in the text box to its right.
  • Target grid – This is a required input parameter. Specify which grid/mesh the quadratic friction dataset will be created for.
  • Default quadtratic friction option – Set the default value to use in computing the quadtratic friction using the area not represented in the values. This can be set to "Constant" to use a constant value or set "Dataset" to select a dataset to use.
    • Default quadtratic friction value – Enter the a value to use as a constant default value.
    • Default quadtratic friction dataset – Select a dataset to use as a default value.
  • Subset mask dataset – This optional option allows using a dataset as a subset mask.
  • Output quadtratic friction dataset – Enter the name for the new quadtratic friction dataset.

If the landuse type is chosen as NLCD or C-CAP, the default values below are used in the calculation. If there is a different landuse raster type, or wishing to use values that differ from the defaults, specify the raster type as "Custom" and provide a CSV file with the desired values.

Quadratic Friction NLCD Mapping Table

Quadratic Friction NLCD Values
Code Description Friction
0 Background 0.002
1 Unclassified 0.002
11 Open Water 0.0018
12 Perennial Ice/Snow 0.00046
21 Developed Open Space 0.0018
22 Developed Low Intensity 0.011
23 Developed Medium Intensity 0.046
24 Developed High Intensity 0.1
31 Barren Land (Rock/Sand/Clay) 0.037
41 Deciduous Forest 0.046
42 Evergreen Forest 0.055
43 Mixed Forest 0.046
51 Dwarf Scrub 0.0073
52 Shrub/Scrub 0.011
71 Grassland/Herbaceous 0.0053
72 Sedge/Herbaceous 0.0041
73 Lichens 0.0033
74 Moss 0.0028
81 Pasture/Hay 0.005
82 Cultivated Crops 0.0062
90 Woody Wetlands 0.046
95 Emergent Herbaceous Wetlands 0.0092
91 Palustrine Forested Wetland 0.046
92 Palustrine Scrub/Shrub Wetland 0.01
93 Estuarine Forested Wetland 0.046
94 Estuarine Scrub/Shrub Wetland 0.01
96 Palustrine Emergent Wetland (Persistent) 0.0092
97 Estuarine Emergent Wetland 0.0092
98 Palustrine Aquatic Bed 0.001
99 Estuarine Aquatic Bed 0.001


Directional Roughness CCAP Mapping Table

Directional Roughness CCAP Values
Code Description Roughness
0 Background 0
1 Unclassified 0
2 Developed High Intensity 0.55
3 Developed Medium Intensity 0.4
4 Developed Low Intensity 0.3
5 Developed Open Space 0.1
6 Cultivated Crops 0.06
7 Pasture/Hay 0.06
8 Grassland/Herbaceous 0.04
9 Deciduous Forest 0.65
10 Evergreen Forest 0.72
11 Mixed Forest 0.71
12 Scrub/Shrub 0.12
13 Palustrine Forested Wetland 0.55
14 Palustrine Scrub/Shrub Wetland 0.12
15 Palustrine Emergent Wetland (Persistent) 0.11
16 Estuarine Forested Wetland 0.55
17 Estuarine Scrub/Shrub Wetland 0.12
18 Estuarine Emergent Wetland 0.11
19 Unconsolidated Shore 0.03
20 Barren Land 0.04
21 Open Water 0.001
22 Palustrine Aquatic Bed 0.03
23 Estuarine Aquatic Bed 0.03
24 Perennial Ice/Snow 0.012
25 Tundra 0.03