OS Terrain 50

This page lists the methods that deal with loading the OS Terrain 50 data set.

Alphabetical list:

• DataNotFoundError()

• download_os_terrain_50

• gb()

• spacing()

Accessing the data

nevis.gb(downsampling=None)

Returns an array of elevation data for Great Britain, with height in meters and grid points spaced 50m apart.

Array indices are (height, width), also known as (northings, eastings).

A downsampled version can be returned for testing purposes, by setting downsampling to any integer greater than one.

nevis.spacing()

Returns the spacing between any two grid points.

Checking if points are sea or just below sea-level

nevis.inland_below_sea_level()

Returns a list of points (x, y) in meters that are below sea-level, but which nevis’s preprocessing did not consider to be “sea”.

nevis.is_sea(coords)

Returns True if and only if the given nevis.Coords were classified as “sea” by nevis’s pre-processing.

Downloading the data

nevis.download_os_terrain_50(force=False)

Downloads, unpacks and processes the OS Terrain 50 data set.

If a previously downloaded zip file is found then the downloading step is skipped, unless force is set to True.

If a previously unpacked and processed file is found, this method does nothing unless force is set to True.

class nevis.DataNotFoundError

Raised when the OS Terrain 50 data is not found.

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.