Development of a base layer for DOPA.


DOPA spreads indicators based on WDPA dataset, “interrogated” (spatially intersected) by other datasets.
Base datasets for the above process are:
  1. Country boundaries
  2. Ecoregions boundary

Country boundaries


Sources for this dataset are:
  1. GAUL (http://www.fao.org/geonetwork/srv/en/metadata.show?id=12691), last version available (revision 2015): global administrative units
    a001_gaul.jpg
    GAUL data source
  2. EEZ (http://www.marineregions.org/downloads.php), last version available (V9, 2016): Exclusive Economic Zone of countries
    a003_eez.jpg
    EEZ data source

The two datasets come with different coastline, different attributes structure (with only one common field: ISO3), and small differences within the content (not all changed sovereignty countries are updated).
Normalization of these two datasets involved:

  • Intersection: where there is overlap, GAUL wins
  • gap filling: where there is a gap within the two coastline, this is filled and attributed to the containing EEZ
    a002_holes.jpg
    gaps (yellow) due to different coastline within GAUL (brown) and EEZ (blue)
  • unification of the attributes structure
  • identification of Disputed, Joint Managed areas, and attribution to multiple ISO3 codes
  • identification of the areas not covered by any of the two dataset as Area Beyond National Jurisdiction (ABNJ)
  • identification of updated information according to ISO 3166-1 standard
  • dissolve to remove non-unique keys, where present
  • geometric simplification (topology aware)
  • JOIN with ancillary information to include additional codes (ISO2 and ISO numeric/UN_M49)
  • JOIN with ancillary information to get country grouping information (UN_M49 as key).

The result is a dataset with updated geometries and structure, which maintains original source codes (ADM0 for GAUL, MRGID for EEZ).
01_eez_gaul_abnj.jpg
Merged GAUL (brown) and EEZ (blue); ABNJ is green

Ecoregions boundaries


Sources for this dataset are:

  1. Terrestrial Ecoregions of the World (TEOW; https://www.worldwildlife.org/publications/terrestrial-ecoregions-of-the-world): biogeographic regionalization of the Earth's terrestrial biodiversity.
    B001_teow.jpg
    TEOW
  2. Marine Ecoregions and Pelagic Provinces of the World (MEOW/PPOW; http://data.unep-wcmc.org/datasets/38 ): biogeographic classification of the world’s coastal, continental shelf, and surface pelagic waters. This dataset combines two separately published datasets:
    1. the “Marine Ecoregions Of the World” (MEOW; 2007)
      B002_meow.jpg
      MEOW
    2. “Pelagic Provinces Of the World” (PPOW; 2012
      B003_ppow.jpg
      PPOW

The two datasets come with different attributes structure.
Normalization of these two datasets involved:
  • Intersection: where there is overlap (MEOW/PPOW comes without coastline), TEOW wins
  • unification of the attributes structure.
03_ecoregions.jpg
Merged TEOW (green), MEOW (yellow) and PPOW (blue)

Unified BASE Layer


To reduce the number of processing loops to iterate on the WDPA, the two above datasets are merged.
The target is to get, with a single processing cycle, information on:
  • country
  • ecoregion
  • land/marine
  • all related to the above, as:
    • number of PAs for country
    • number of marine/terrestrial PAs for Country
    • number of PAs for ecoregion
    • and so on…
Merging of the two datasets involved:
  • dissolve of the country/eez on country codes (source information, eez or gaul, is discarded; consequently the land/sea information is dissolved in bigger polygons which contains both the objects).
    02_countries.jpg
    GAUL/EEZ dissolved
  • Intersect (UNION) of the geometries and attributes of the result from previous step, and ecoregions.
    04_countries_ecoregions.jpg
    Merged country/ecoregion dataset

Each polygon contained in the resulting dataset contains information on ecoregions (teow, meow,ppow original codes), country (iso3/iso2/un_m49), land/sea (given by teow coastline, which is lower resolution than the GAUL one).
05_countries_ecoregions_terrestrial.jpg
Land (yellow) and marine (brown) information in the country/ecoregion base layer.

06_countries_ecoregions_terrestrial_compare_1-250k.jpg
Comparison of GAUL coastline (transparent) overlaid on TEOW coastline (green).