New model for geospatial coverages in JSON: Coverage implementation schema and its implementation with javascript

Abstract

Map browsers currently in place present maps and geospatial information using common image formats such as JPEG or PNG, usually created from a service on demand. This is a clear approach for a simple visualization map browser but prevents the browser from modifying the visualization since the content of the image file represents the intensity of colors of each pixel. In a desktop GIS, a coverage dataset is an array of values quantifying a certain property in each pixel of a subdomain of the space. The standard used to describe and distribute coverages is called web coverage service (WCS). Traditionally, encoding of coverages was too complex for map browsers implemented in JavaScript, relegating the WCS to a data download, a process that creates a file that will be later used in a desktop GIS. The combination of a coverage implementation schema in JSON, binary arrays, and HTML5 canvas makes it possible that web map browsers can be directly implemented in JavaScript.