analysis API Reference¶

Top-level functions for python-tidegates.

This contains main functions to evaluate the extent of floodinga and damage due to floods.

3. Geosyntec Consultants, 2015.

Released under the BSD 3-clause license (see LICENSE file for more info)

Written by Paul Hobson (phobson@geosyntec.com)

tidegates.analysis.process_dem_and_zones(dem, zones, ID_column, cleanup=True, **verbose_options)¶

Convert DEM and Zones layers to numpy arrays.

This is a pre-processor of the DEM and Zone of Influent input data. Both are converted to numpy arrays and returned along with a raster template so that the arrays can be correctly georeferenced if necessary. These returned values are intended to be fed directly to flood_area().

Parameters:	dem : str or arcpy.Raster The topographic data needed to assess flood impacts. zones : str or arcpy.mapping.Layer The shapefile or feature class representing the tidegates’ zones of influence. ID_column : str Name of the column in the attribute table of zones that uniquely identifies each tidegate. cleanup : bool, optional (True) Toggles the removal of temporary files.
Returns:	topo_array, zones_array : numpy.ndarray Arrays of the topo data and zones of influence. template : tidegates.utils.RasterTemplate A raster template that can be used to georeference the returned arrays.
Other Parameters:
	verbose : bool (default = False) Toggles the printing of messages communication the progress of the processing. asMessage : bool (default = False) When True, progress messages are passed through arcpy.AddMessage. Otherwise, the msg is simply printed to stdin.

See also

flood_area, tidegates.utils.RasterTemplate

tidegates.analysis.flood_area(topo_array, zones_array, template, ID_column, elevation_feet, filename=None, cleanup=True, **verbose_options)¶

Mask out portions of a a tidegates area of influence below a certain elevation.

Parameters:	topo_array : numpy array Floating point array of the digital elevation model. zones_array : numpy array Categorical (integer) array of where each non-zero value delineates a tidegate’s zone of influence. template : arcpy.Raster or utils.RasterTemplate A raster or raster-like object that define the spatial extent of the analysis area. Required attributes are: templatemeanCellWidth templatemeanCellHeight templateextent.lowerLeft ID_column : str Name of the column in the zones layer that associates each geomstry with a tidegate. elevation_feet: float The theoritical flood elevation (in ft MSL) that will be analyzed. filename : str, optional Filename to which the flooded zone will be saved. cleanup : bool (default = True) When True, temporary results are removed from disk.
Returns:	flood_zones : arcpy.mapping.Layer arcpy Layer of the zones showing the extent flooded behind each tidegate.
Other Parameters:
	verbose : bool (default = False) Toggles the printing of messages communication the progress of the processing. asMessage : bool (default = False) When True, progress messages are passed through arcpy.AddMessage. Otherwise, the msg is simply printed to stdin.

See also

process_dem_and_zones, assess_impact, area_of_impacts, count_of_impacts

tidegates.analysis.assess_impact(floods_path, flood_idcol, cleanup=False, wetlands_path=None, wetlands_output=None, buildings_path=None, buildings_output=None, bldg_idcol='STRUCT_ID', **verbose_options)¶

Assess the extent of damage due to flooding in wetlands and buildings.

Parameters:	floods_path : str or arcpy.mapping.Layer The (filepath to the) layer of the extent of flooding. Ideally, this layer should be generated with flood_area. flood_idcol : str Name of the column in the floods_path layer that associates each geomstry with a tidegate. wetlands_path, buildings_path : str Paths to layers containing wetlands and building footprints. wetlands_output, buildings_output : str Path to where the final output of the assessed damage to the wetlands and buildings should be saved. cleanup : bool (default = True) When True, temporary results are removed from disk.
Returns:	flooded_areas : arcpy.mapping.Layer flooded_wetlands : arcpy.mapping.Layer flooded_buildings : arcpy.mapping.Layer
Other Parameters:
	verbose : bool (default = False) Toggles the printing of messages communication the progress of the processing. asMessage : bool (default = False) When True, progress messages are passed through arcpy.AddMessage. Otherwise, the msg is simply printed to stdin.

See also

flood_area, area_of_impacts, count_of_impacts

tidegates.analysis.area_of_impacts(*args, **kwargs)¶

Computes the area of assets impacted by a flooded area.

The impacted area is anywhere an asset and the flooded areas overlap. This is useful for such tasks as determine the amount of wetlands inundated by a flood.

Parameters:

floods_path : str Path/filename of the dataset of flooded areas. Ideally this is output from flood_area(). flood_idcol : str Name of the field in floods_path that associates each flooded area with a tidegate. assets_input : str Path/filename of the dataset of assets (e.g., wetland boundaries). fieldname : str, optional (‘wetlands’) The name of the field that will be added to floods_path containing the count of impacted assets for each flooded area. assets_output : str, optional Path/filename of the dataset in which only the impacted assets will be saved.

Returns:

flooded_assets : arcpy.mapping.Layer Layer of the flooded assets.

See also

flood_area, assess_impact, count_of_impacts

tidegates.analysis.count_of_impacts(*args, **kwargs)¶

Counts of the number of assets impacted by a flooded area.

An asset is considered impacted if a flooded area overlaps its boundary in anyway. This is useful for such tasks as counting the number of building footprints within a flood area.

Parameters:

floods_path : str Path/filename of the dataset of flooded areas. Ideally this is output from flood_area(). flood_idcol : str Name of the field in floods_path that associates each flooded area with a tidegate. assets_input : str Path/filename of the dataset of assets (e.g., building footprints). fieldname : str, optional (‘buildings’) The name of the field that will be added to floods_path containing the count of impacted assets for each flooded area. assets_output : str, optional Path/filename of the dataset in which only the impacted assets will be saved.

Returns:

touched_assets : arcpy.mapping.Layer Layer of the impacted assets.

See also

flood_area, assess_impact, area_of_impacts