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Tool Facility Land Cover Views

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donebert edited this page Aug 23, 2022 · 23 revisions

Facility Land Cover Views

Summary

Counts the number of facilities in each reporting unit polygon that have less than a certain percentage of selected land cover classes within a given distance and creates an output table. The percentage threshold value and buffer distance are provided by the user.

Usage

  • This tool processes all polygons in the Reporting unit feature regardless of selections set. The ability to limit metric calculations to only selected reporting unit polygons is not supported in this release.

  • NOTE: To ensure desired results, the Reporting unit feature, Land cover grid, and Facility feature must be in projected coordinate systems with linear units of measure.

  • The Reporting unit feature is a zone dataset.

    • A zone is defined as all areas in the input that have the same value. The areas do not have to be contiguous. The term "value" in this definition refers to the unique values in the Reporting unit ID field. Therefore, all polygons with the same reporting unit ID are treated as a single zone.

    • When more than one polygon has the same reporting unit ID, the areas for each polygon are combined and metrics are reported as a single record in the Output table.

    • NOTE: Reporting units without overlapping data in the secondary inputs (e.g., land cover grid), may be excluded from the Output table.

  • WARNING: If a feature in the Reporting unit feature zone data does not overlap any cell centers of the Land cover grid class raster, those zones will not get converted to the internal zone raster. As a result, those zones will not be represented in the output.

  • The tool buffers a copy of the points in the Facility feature and uses Tabulate Area to calculate the percentage of the buffer area that is a selected land cover class. Tabulate Area performs a vector to raster conversion of the buffer area to use as zones for its operation. Results may vary depending on the settings of the Raster Analysis Cell Size and Snap Raster Environment settings

    • To better control the vector to raster conversion, the tool defaults the Snap raster and the Processing cell size to that of the Land cover grid. These may be changed from within the tool.

    • If a significant disparity exists between the extents of the Reporting unit feature and the Land cover grid, the user may wish to set the Extent in Environment Settings > Processing Extent to the smaller of the two to avoid unnecessary processing.

  • The Land cover classification scheme must correspond to the Land cover grid.

    • Schemes for common land cover datasets are included with ATtILA. Supplied schemes may be designated as either "ALL" or "LAND" (e.g. NLCD 2001 ALL vs. NLCD 2001 LAND). Schemes designated as "ALL" include all land cover classes in the metric calculations, while those designated as "LAND" include only terrestrial land cover classes, with non-terrestrial land cover classes such as water and snow/ice excluded. More information about each of the classification schemes supplied with ATtILA may be found in Supplied Land Cover Classification Schemas section of the User Manual.

    • In addition to the common land cover schemes, the tool permits a user-defined land cover classification scheme to be used by specifying a Land cover classification file (.xml). Refer to Land Cover Classification in the User Manual for more information.

    • NOTE: When a classification scheme with excluded land cover classes is selected, the areas of the excluded classes are disregarded in metric calculations. For example, when selecting a "LAND" classification scheme, the tool will process individual land cover classes and calculate metrics based on the total terrestrial area they occupy within the reporting unit, rather than the percent of the total area within the reporting unit.

  • Final output is written to the location specified in the Output table parameter. The Output table may be saved as a File Geodatabase Table, or a dBASE Table.

    • NOTE: For most consistent results, it is highly recommended that tool output be saved to a file geodatabase.

    • When saving as a File Geodatabase Table, no extension is necessary for the Output table name. The output location must be a file geodatabase.

    • When saving as a dBASE Table, include the .dbf extension in the Output table name. dBASE tables may not be saved in a file geodatabase.

  • In Additional Options, the user may elect to Retain Intermediate Layers Generated During Metric Processing.

    • Choosing to Retain Intermediate Layers saves the intermediate products to one of the following locations:

      • When output is saved as a File Geodatabase Table, intermediate products are placed in the same file geodatabase.

      • When output is saved as a dBASE Table, a file geodatabase named "attilaScratchWorkspace" is automatically generated in the same output location specified for the Output table. Intermediate products are placed in the attilaScratchWorkspace file geodatabase.

  • Generated intermediate layers produced are:

    • flcv_Facility - Copy of the Facility feature with all but the OBJECTID and Shape fields removed.

    • flcv_FacilityRUID - Copy of the flcv_Facility feature with the overlying Reporting unit feature's ID attached via Identity. A facility point that occurs in overlapping Reporting Unit feature areas will produce a separate output feature for each of the Reporting unit features it occurs in.

    • flcv_ViewBuffer - flcv_FacilityRUID feature buffered to the View radius. The attribute table will contain fields for the Reporting unit feature ID, the buffer distance (View radius), and a field named, 'ORIG_FID'. The ORIG_FID is used as a unique identifier for future operations to tag each facility/reporting unit combination.

    • flcv_TabArea - Tabulate Area output table using flcv_ViewBuffer's ORIG_FID field as the zone identifier and the Land cover grid as the raster to be summarized.

    • flcv_ViewLCP - Table containing the percentage of each facility's view buffer area composed of selected land cover classes. Additional fields in the attribute table include FLCV_TOTA, FLCV_EFFA, FLCV_EXCA, and a separate field for each selected land cover class named, [class]_Below.

      • FLCV_TOTA is the sum of the Land cover grid cell areas within the View radius.

      • FLCV_EFFA is the sum of the Land cover grid cell areas within the View radius that are not marked as "Excluded' in the Land cover classification scheme XML file.

      • FLCV_EXCA is the sum of the Land cover grid cell areas within the View radius that are marked as "Excluded' in the Land cover classification scheme XML file.

      • [class]_Below is a binary field where land cover class percentage below View threshold = 1, and land cover class percentage at or above View threshold = 0.

    • flcv_ViewLCP_RUID - The flcv_ViewLCP table with the Reporting unit feature ID field attached. The ID was obtained by a join with the flcv_FacilityRUID table and the common 'ORIG_FID' field.

    • flcv_ViewStats - Summary Statistics output table where each [class]_Below field in the flcv_ViewLCP_RUID table is summed by Reporting unit feature ID.

    NOTE: All filenames, with the exception of flcv_TabArea, will end in the string, '###_X', where ### is the supplied View radius, and X is a generated incremental number to provide a unique filename. Flcv_TabArea will not have the View radius in its filename.

  • Field names in the Output table follow this naming scheme:

    • [class]_Low[view threshold] - The number of facilities in the reporting unit with percentages of the selected land cover class below the View threshold value in facility's buffer area. For example, values in a field named "for_25" would represent the number of facilities in the reporting unit that have less than 25 percent of land occupied by the NLCD "Forest" class within their view buffers.

    • NOTE: The output field name for each class is shown as the second item next to the class's check box in Report metrics for these classes.

    • NOTE: Output field names can be altered by editing the Land cover classification file.

  • FAC_Count will be included in the Output table as an ancillary field. It reports the total number of facilities in the reporting unit.

Syntax

FLCV (Reporting_unit_feature, Reporting_unit_ID_field, Land_cover_grid, Land_cover_classification_scheme, Land_cover_classification_file, Report_metrics_for_these_classes, Facility_feature, View_radius, View_threshold, Output_table, {Processing_cell_size}, {Snap_raster}, {Select_options})

Parameter Explanation Data Type
Reporting_unit_feature The vector polygon dataset that defines the reporting units. Feature Layer
Reporting_unit_ID_field The field in the Reporting unit feature layer that contains the unique ID for each reporting unit.

It may be an integer or a string data type.		 Field
Land_cover_grid The raster dataset representing land cover classes to be summarized within each Reporting unit feature.

The grid input must be an integer raster layer.		 Raster Layer
Land_cover_classification_scheme The land cover classification schemes included in ATtILA and a User Defined option.

The default schemes correspond to common input land cover datasets. Two schemes are supplied for each dataset included in ATtILA:

  • {DATASET NAME} ALL - includes all land cover types in the grid with no exclusions.
  • {DATASET NAME} LAND - excludes non-terrestrial land cover types.
 String
Land_cover_classification_file The full pathname to the user-defined .xml file for custom or non-standard land cover classification schemes.

Pathname is automatically filled when a default scheme is selected.		 File
Report_metrics_for_these_classes A list of the land cover classes and metric combinations for processing.

Check the box to calculate metrics for each land cover class and/or combination class desired within the reporting units.		 Multiple Value
Facility_feature The vector point dataset that provides the basis for the buffer zones.

Land cover proportions are calculated for the area within the buffer zones.		 Feature Layer
View_radius The distance around the Facility point features which comprises the buffer zones.

The value must be an integer.

If the distance linear units are not specified or are entered as Unknown, the linear unit of the input features' spatial reference is used.		 Linear Unit
View_threshold The percentage value below which a land cover class's presence in the buffer zone is identified as low. Double
Output_table The output reporting unit metrics table to be created.

It is recommended that the Output table be saved within a file geodatabase.		 Table
Processing_cell_size (Optional) The Processing cell size for the zonal operation.

The default Processing cell size is the cell size of the input raster land cover data. Optionally, the user may select a different cell size.		 Analysis Cell Size
Snap_raster (Optional) The raster that the cell alignment of the Land cover grid and rasterized Reporting unit feature layer will be matched to during processing.

The default Snap raster is the Land cover grid.		 Raster Layer
Select_options (Optional) One tool option is available to provide additional information:

  • Retain Intermediate Layers Generated During Metric Calculation - Saves the intermediate data layers that are normally deleted after processing is complete.
 Multiple Value

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