News

November 04, 2016 - Ward Appeltansdatabase

Line transects and polygons

There is often a misconception that OBIS is only about point data. Below is a nice example of a dataset from OBIS Canada with almost 10,000 line transects over a 50-year period (go to the dataset page on OBIS). OBIS has always allowed start-end coordinates and bounding boxes in the past. With the new DarwinCore standard these location features (including more complicated line strings and polygons!) are stored in DwC: footprintWKT.

Some examples of WKT strings from the OBIS manual:

LINESTRING (30 10, 10 30, 40 40)
POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))
MULTILINESTRING ((10 10, 20 20, 10 40),(40 40, 30 30, 40 20, 30 10))
MULTIPOLYGON (((30 20, 45 40, 10 40, 30 20)),((15 5, 40 10, 10 20, 5 10, 15 5)))

Note there is a WKT mapping tool at http://iobis.github.io/map/.

line-strings-2833.png