Distance to the nearest land/coastline (including small subantarctic islands) for the five-minute average cruise track of the Antarctic Circumnavigation Expedition (ACE) during the austral summer of 2016/2017.

***** Dataset abstract *****

This dataset is derived from: 
- The GPS track of the R/V-Akademik Tryoshnikov (10.5281/zenodo.3772377)
- The shapefiles of the continents from NaturalEarth physical (@50m), version 4.1.0, 
downloadable at [https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/physical/ne_50m_land.zip](https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/physical/ne_50m_land.zip)
- A manual entry of the smaller islands which may not be mapped on the NaturalEarth resource, namely: 
    - "Peter I": [-68.8282, -90.6157]
    - "Scott": [-67.3783, -179.9117]
    - "Young": [-66.2833, 162.4167]
    - "Buckle": [-66.65, 163.05]
    - "Sturge": [-67.416667, 164.733333]
    - "Siple": [-73.65, -125]
    - "Bouvetoya": [-54.4208, 3.3464]

The calculation of the actual distance to land has been done in qGIS 3.2.3-Bonn https://qgis.org/downloads/, using the NNJoin plugin version 3.1.2 https://plugins.qgis.org/plugins/NNJoin/. After the point-to-closest polygon distance calculation, the python script in src/add_distance_to_small_islands.py replaces the distance calculation to the centerpoint of the islands (as reported above) if the boat is closer to the island centerpoint than any other coast. 

Data file: dist_to_land_incl_small_islands.csv

***** Original data collection *****

The intermediate processing steps and files which take us from the input dataset (10.5281/zenodo.3772377) and the distance to land derived in qGIS to this final set of output files can be seen in the dataset presented here. This dataset is a direct output of these intermediate processing steps.

***** Data processing *****

To produce this data file use `src/add_distance_to_small_islands.py` after computing the distance of the shiptrack (10.5281/zenodo.3772377) to land (shapefiles of the continents from NaturalEarth physical, @50m, version 4.1.0). 
The distance is calculated in qGIS 3.2.3-Bonn (https://qgis.org/downloads/), using the NNJoin plugin version 3.1.2 (https://plugins.qgis.org/plugins/NNJoin/).

The data repository can be checked out at: https://renkulab.io/gitlab/ACE-ASAID/cruise-track-distance-to-land

***** Quality checking *****

No quality measures where applied to the data.

***** Standards *****
 
This dataset does not conform to any data formats or standards. 

***** Further information for interpreting the data and using the dataset *****

Timescales: the time scale of the distance is variable and depends of the speed of the ship.

Interpolation: Interpolation to finer resolution is no problem but likely not useful

Aggregation to lower temporal resolution: No problem but depending on the application this should be done using mean, median, minimu or maximum.

***** Dataset contents *****

- dist_to_land_incl_small_islands.csv, data file, comma-separated values
- data_file_header, metadata, text format
- README.txt, metadata, text format
- add_distance_to_small_islands.py, python script, text format

***** Dataset contact *****

Michele Volpi, Swiss Data Science Center, ETH Zurich. ORCID: 0000-0003-2771-0750. Email: michele.volpi@datascience.ch

***** Dataset license *****

This output to the five-minute averaged distance to land is made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0) whose full text can be found at https://creativecommons.org/licenses/by/4.0/

***** Dataset citation *****

Please cite this dataset as:
Volpi, M., S. Landwehr, J. Thomas and J. Schmale. (2020). Ship distance to land (including subantarctic islands) for the five-minute average cruise track of the Antarctic Circumnavigation Expedition (ACE) during the austral summer of 2016/2017. (Version 1.0) [Data set]. Zenodo.