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This model combines the first three pre-processing steps in the raster dasymetric mapping routine. First, it converts a polygon feature class to an integer raster using the ObjectID of the feature class for the value of the output raster. Next, it combines the population raster and an ancillary raster and creates a standalone table for dasymetric calculations. Last, it creates a standalone table that can contain preset density values for all the unique classes in the ancillary dataset. After the table is created, it will need to be manually populated with preset density values, and classes that should not be preset should be removed from the table.
The output table will contain ancillary class values, the count of the number of pixels in that class, and a new column with floating-point type called PRESETDENS, which represents estimated people per pixel. It is most common for this function to be used to specify zero population for certain classes (it's often a safe assumption that water or snowfield areas have zero population). Setting such classes to zero helps refine density estimates in the intelligent dasymetric mapping. You may finish preparing this table in at least two ways:
You should remove rows from the table corresponding to those classes for which you do not wish to provide estimates (you would prefer their densities to be calculated via intelligent dasymetric mapping).
Expression | Explanation |
---|---|
<Population_Features> |
The population input polygon featureclass to be converted to a raster. |
<Population_Count_Field> |
Specify the field in the population dataset that contains count data. |
{Population_Key_Field} |
Since the tool will always use the system-recognized ObjectID field for the output raster Values, this is for your reference only and is not used by the tool. It can be helpful to have another key field (commonly census FIPS code) for joining the outuput raster to other tables. |
<Population_Raster> |
The output population raster dataset that will be created, inlcuding the full path. When you're not saving to a geodatabase, specify .tif for a TIFF file format, .img for an ERDAS IMAGINE file format, or no extension for a GRID file format. |
<Population_Working_Table> |
The tool will create a standalone table for performing calcluations. Please enter a name and path for the output table. |
{CELL_CENTER | MAXIMUM_AREA | MAXIMUM_COMBINED_AREA} |
The method to determine how the cell will be assigned a value when more than one feature falls within a cell.
|
<Ancillary_Raster> |
The ancillary raster dataset to be used to redistribute population. The output raster from this tool will be snapped to the ancillary raster and have matching spatial reference and cell size. Land-use or land-cover are the most frequently used ancillary datasets, but any dataset that has classes of relatively homogenous population density could be used here. |
<Ancillary_Preset_Table> |
The output standalone table with full path that will be created. If your workspace is a geodatabase, no file extension is necessary, otherwise, please be sure to include a .dbf extension. |
<Dasymetric_Raster> |
Enter a name and full path for the output dasymetric raster. A common choice is dasyraster. This raster will have a single value for each unique combination of population units and ancillary classes. When you're not saving to a geodatabase, specify .tif for a TIFF file format, .img for an ERDAS IMAGINE file format, or no extension for a GRID file format. |
<Dasymetric_Working_Table> |
Enter a name and full path for the output dasymetric working table A common choice is dasyworktable. Performing calculations on a standalone table is more predictable than trying to perform calculations on a raster value attribute table. If your workspace is a geodatabase, no file extension is necessary, otherwise, please be sure to include a .dbf extension. |
Expression | Explanation |
---|---|
Population Features (Required) |
The population input polygon featureclass to be converted to a raster. |
Population Count Field (Required) |
Specify the field in the population dataset that contains count data. |
Population Key Field (Optional) |
Since the tool will always use the system-recognized ObjectID field for the output raster Values, this is for your reference only and is not used by the tool. It can be helpful to have another key field (commonly census FIPS code) for joining the outuput raster to other tables. |
Population Raster (Required) |
The output population raster dataset that will be created, inlcuding the full path. When you're not saving to a geodatabase, specify .tif for a TIFF file format, .img for an ERDAS IMAGINE file format, or no extension for a GRID file format. |
Population Working Table (Required) |
The tool will create a standalone table for performing calcluations. Please enter a name and path for the output table. |
Cell Assignment Type (Optional) |
The method to determine how the cell will be assigned a value when more than one feature falls within a cell.
|
Ancillary Raster (Required) |
The ancillary raster dataset to be used to redistribute population. The output raster from this tool will be snapped to the ancillary raster and have matching spatial reference and cell size. Land-use or land-cover are the most frequently used ancillary datasets, but any dataset that has classes of relatively homogenous population density could be used here. |
Ancillary Preset Table (Required) |
The output standalone table with full path that will be created. If your workspace is a geodatabase, no file extension is necessary, otherwise, please be sure to include a .dbf extension. |
Dasymetric Raster (Required) |
Enter a name and full path for the output dasymetric raster. A common choice is dasyraster. This raster will have a single value for each unique combination of population units and ancillary classes. When you're not saving to a geodatabase, specify .tif for a TIFF file format, .img for an ERDAS IMAGINE file format, or no extension for a GRID file format. |
Dasymetric Working Table (Required) |
Enter a name and full path for the output dasymetric working table A common choice is dasyworktable. Performing calculations on a standalone table is more predictable than trying to perform calculations on a raster value attribute table. If your workspace is a geodatabase, no file extension is necessary, otherwise, please be sure to include a .dbf extension. |
Name | Explanation |
---|---|
Raster 1 - Population Features to Raster | |
Raster 2 - Combine Population and Ancillary Rasters | |
Raster 3 - Create Ancillary Class Preset Table |