SIGRID-3 : A vector archive format for sea ice charts: developed by the International Ice Charting Working Group's Ad Hoc Format Team for the WMO Global Digital Sea Ice Data Bank Project.

Abstract

This document describes the SIGRID-3 format so that it may be understood by a variety of users and implemented by chart-producing ice centers or services. SIGRID-3 evolved from earlier SIGRID formats and incorporates much of their content. WMO ice chart archive formats are the Sea Ice Grid (SIGRID) format developed in 1981 and formalized in 1989, and its successor SIGRID-2. The vector format defined in this document, SIGRID-3, joins SIGRID and SIGRID-2 as standard WMO formats. SIGRID-3 is based on a format called "shapefile". The shapefile format is an open vector file format. In contrast to raster formats such as SIGRID-2, where ice characteristics are represented on a grid, vector formats represent features (such as areas of ice outlined on a chart) as a series of vertices that define the outline of the feature in space. An associated list of attributes (such as the concentration, stage of development, and form of ice within) characterizes ice within the outlined area.