source_importers¶

source_importers ¶

Source importers from GIS / CAD formats.

Permit consultants typically receive site plans as Esri shapefiles (.shp) from GIS staff and AutoCAD drawings (.dxf) from civil and mechanical engineers. This module turns either into pyaermod source dataclasses, ready to drop into a :class:SourcePathway.

Two importers are exposed:

:func:from_shapefile — depends on the geo extra (geopandas).
:func:from_dxf — depends on the cad extra (ezdxf), which is lightweight (~5 MB, MIT-licensed, pure Python).

The mapping from geometry to source type follows EPA convention:

============================== ============================== Geometry Default pyaermod source type ============================== ============================== Point / Point Z :class:PointSource Polygon / Polygon Z :class:AreaPolySource LineString / LineString Z :class:LineSource ============================== ==============================

Caller can override the default via source_type= to map every imported feature to a specific class (e.g. RLineSource instead of LineSource for roadway centerlines). Per-feature attribute columns (emission_rate, stack_height, etc.) are looked up by name on each feature; missing columns fall back to the keyword defaults on the dataclass.

VolumeSource `dataclass` ¶

AERMOD volume source

Represents a three-dimensional volume with initial dispersion. Useful for modeling emissions from buildings, structures, or areas with significant initial mixing.

set_building_from_bpip ¶

set_building_from_bpip(building) -> None

Populate building downwash fields from a Building object.

to_aermod_input ¶

to_aermod_input() -> str

Generate AERMOD SO pathway text for this source

from_shapefile ¶

from_shapefile(path: Union[str, Path], *, src_id_field: str = 'source_id', source_type: Optional[Type] = None, attribute_map: Optional[dict] = None, layer: Optional[str] = None) -> List

Import sources from an Esri shapefile (or any geopandas-readable file).

Parameters:

Name	Type	Description	Default
`path`	`Union[str, Path]`	Path to the .shp (or .gpkg / .geojson / etc.). Anything `geopandas.read_file` accepts.	required
`src_id_field`	`str`	Attribute column to use for the source_id. Falls back to `"SRC0001"`-style synthesized IDs when missing.	`'source_id'`
`source_type`	`Optional[Type]`	Override default geometry → source class mapping. For example pass `RLineSource` to mark all imported lines as roadways.	`None`
`attribute_map`	`Optional[dict]`	Optional mapping of {shapefile_attribute: source_field}, e.g. `{"H_M": "stack_height", "Q": "emission_rate"}`.	`None`
`layer`	`Optional[str]`	For multi-layer formats (e.g. GPKG), the layer name to read.	`None`

Returns:

Type	Description
`list of source dataclass instances ready for SourcePathway(sources=[...]).`

Raises:

Type	Description
`ImportError`	If geopandas is not installed (pip install pyaermod[geo]).

from_dxf ¶

from_dxf(path: Union[str, Path], *, layer: Optional[str] = None, src_id_prefix: str = 'DXF', source_type: Optional[Type] = None, z_as_height: bool = False) -> List

Import sources from an AutoCAD DXF file.

Maps DXF geometry to pyaermod sources::

POINT      -> PointSource (or VolumeSource when source_type passed)
LWPOLYLINE -> AreaPolySource (closed) or LineSource (open)
POLYLINE   -> same as LWPOLYLINE
LINE       -> LineSource
CIRCLE     -> AreaPolySource (16-vertex approximation)

Parameters:

Name	Type	Description	Default
`path`	`Union[str, Path]`	Path to the .dxf file.	required
`layer`	`Optional[str]`	Restrict import to entities on a single named DXF layer.	`None`
`src_id_prefix`	`str`	Prefix for synthesized source IDs (DXF doesn't natively carry source_id-like attributes).	`'DXF'`
`source_type`	`Optional[Type]`	Override default geometry → source class mapping.	`None`
`z_as_height`	`bool`	When True, treat each entity's z elevation (or polyline's const_z) as `stack_height` / `release_height`. Useful when CAD models encode building rooftop emission heights.	`False`

Returns:

Type	Description
`list of source dataclass instances.`

Raises:

Type	Description
`ImportError`	If ezdxf is not installed (pip install pyaermod[cad]).

source_importers¶