Skip to content

Hazard

Helpers for location queries using CodedLocation from nzshm-common.

TODO: these coded-location string functions should move to nzshm-common.

downsample_code(loc_code, res)

Get a CodedLocation.code at the chosen resolution from the given location code.

Parameters:

Name Type Description Default
loc_code str

The location code in format 'latitude~longitude'.

 required
resolution int

Resolution in grid degrees to downsample to.

 required

Returns:

Name Type Description
str str

The downsampled location code.

Examples:

>>> downsample_code('37.7749~-122.4194', 0.1)
'37.8~-122.4'
Source code in toshi_hazard_store/query/hazard_query.py 
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
def downsample_code(loc_code, res) -> str:
    """Get a CodedLocation.code at the chosen resolution from the given location code.

    Args:
        loc_code (str): The location code in format 'latitude~longitude'.
        resolution (int): Resolution in grid degrees to downsample to.

    Returns:
        str: The downsampled location code.

    Examples:
        >>> downsample_code('37.7749~-122.4194', 0.1)
        '37.8~-122.4'
    """
    lt = loc_code.split('~')
    assert len(lt) == 2
    return CodedLocation(lat=float(lt[0]), lon=float(lt[1]), resolution=res).code

get_hashes(locs, resolution=0.1)

Compute a set of hashes for the given locations at the specified resolution.

Parameters:

Name Type Description Default
locs Iterable[str]

A collection of location codes in the format 'latitude~longitude'.

 required
resolution float

The resolution to compute hashes at (in grid degrees). Defaults to 0.1.

 0.1

Returns:

Name Type Description
list Iterable[str]

A sorted list of unique location codes, downsampled to the specified resolution.
Source code in toshi_hazard_store/query/hazard_query.py 
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
def get_hashes(locs: Iterable[str], resolution: float = 0.1) -> Iterable[str]:
    """Compute a set of hashes for the given locations at the specified resolution.

    Args:
        locs (Iterable[str]): A collection of location codes in the format 'latitude~longitude'.
        resolution (float, optional): The resolution to compute hashes at (in grid degrees). Defaults to 0.1.

    Returns:
        list: A sorted list of unique location codes, downsampled to the specified resolution.
    """
    hashes = set()
    for loc in locs:
        lt = loc.split('~')
        assert len(lt) == 2
        hashes.add(downsample_code(loc, resolution))
    return sorted(list(hashes))