tracktable.info.shorelines module

Module contents

class tracktable.info.shorelines.Shoreline(resolution='low', level='L1')[source]

Bases: object

Information about a single shoreline

resolution

Fidelity of the given shape

Type:

str

level

Hierarchical level that contains specific information, see the build_shoreline_dict() docstring for more information

Type:

str

polygon

Shapely polygon generated from the points of the given shape

Type:

Shapely Polygon

global_bbox

Lower left and upper right coordinates for the bounding box that encompasses all shapes from the loaded shapefile

Type:

list

shape_bbox

Lower left and upper right coordinates for the bounding box of the given shape in [lon,lat,lon,lat] format

Type:

list

shape_centroid

Center point or centroid for the given shape

Type:

tuple

geojson

GeoJSON formated point information for the given shape

Type:

dicts

points

Non-GeoJSON formated point information for the given shape

Type:

list(tuple)

tracktable.info.shorelines.all_shorelines(resolution='low', level='L1')[source]

Return all the shoreline records at the given level and resolution.

Keyword Arguments:

  • resolution (string) – Resolution of the shapes to pull from the shapefile. (Default: “low”)

  • level (string) – See the docstring for build_shoreline_dict() for more information about levels. (Default: “L1”)

Returns:

List of shoreline objects.

Raises:

ValueError – Unknown resolution or level

tracktable.info.shorelines.all_shorelines_within_bounding_box(bounding_box, resolution='low', level='L1')[source]

Return all the shoreline records that exist in the given given bounding box.

Parameters:

bounding_box (Bounding Box) – Bounding box to return all shoreline from.

Keyword Arguments:

  • resolution (string) – Resolution of the shapes to pull from the shapefile. (Default: “low”)

  • level (string) – See the docstring for build_shoreline_dict() for more information about levels. (Default: “L1”)

Returns:

Dictionary of shorelines from the given bounding box.

Raises:

ValueError – Unknown resolution or level

tracktable.info.shorelines.buffer(points, buffer=10)[source]

Return a buffered shapely polygon for the given set of points.

Parameters:

points (Shapely Points) – Bounding box to return all shoreline from.

Keyword Arguments:

buffer (int) – Distance to buffer in km. (Default: 10)

Returns:

Buffered polygon.

tracktable.info.shorelines.build_shoreline_dict(resolution='low', level='L1')[source]

Assemble the shoreline dictionary on first access

This function is called whenever the user tries to look up a shoreline. It checks to make sure the table has been populated and, if not, loads it from disk.

The geography data come in five resolutions: - full resolution: Original (full) data resolution. - high resolution: About 80 % reduction in size and quality. - intermediate resolution: Another ~80 % reduction. - low resolution: Another ~80 % reduction. - crude resolution: Another ~80 % reduction.

Unlike the shoreline polygons at all resolutions, the lower resolution rivers are not guaranteed to be free of intersections. Shorelines are furthermore organized into 6 hierarchical levels:

  • L1: Continental land masses and ocean islands, except Antarctica.

  • L2: Lakes

  • L3: Islands in lakes

  • L4: Ponds in islands within lakes

  • L5: Antarctica based on ice front boundary.

  • L6: Antarctica based on grounding line boundary.

The top 13 polygons (indices 0-12) in the L1 data are:

Index | Landmass 0 | Eurasia 1 | Africa 2 | North America 3 | South America 4 | Antarctica (AC grounding line) 5 | Antarctica (AC ice line) 6 | Australia 7 | Greenland 8 | New Guinea 9 | Borneo 10 | Madagascar 11 | Baffin Island 12 | Indonesia

Returns:

None

Side Effects:

Shapefile data will be loaded if not already in memory

tracktable.info.shorelines.shoreline_information(index, resolution='low', level='L1')[source]

Retrieve a specific shoreline shape’s information. Shapes are sorted from largest to smallest.

Parameters:

index (int) – Index of the desired shoreline to retrieve information for.

Keyword Arguments:

  • resolution (string) – Resolution of the shapes to pull from the shapefile. (Default: “low”)

  • level (string) – See the docstring for build_shoreline_dict() for more information about levels. (Default: “L1”)

Returns:

Shoreline object at the specified index, resolution and level.

Raises: