VIEWERS

Visualize your data products.

A viewer is a web application to interactively explore content using a map. This document covers the usage and creation of these viewers on portals like Marine Data Portal, Earth Data Portal and the O2A Portal.

There will be a users manual, a creators manual, use-case examples and an FAQ section. Right now, all of these chapters are more-or-less stubs and work in progress.

Context

This section is not relevant for regular users but rather adresses those interested in technical backgrounds.

Viewers exist in the context of portals and map services. The creation and editing (see Creator Manual) of viewers is embedded into portal technology but viewer content is not directly linked to other portal content.

It is important to know that viewers generally do not contain data but embed map services that provide data or data visualisations on-demand. Viewers can embed map services hosted anywhere on the internet as long as those are publicly accessible.

Map services are web services that provide data or data visualisations on-demand to clients like GIS software (e.g. QGIS) and web applications (e.g. our viewers). They are standardised – making them interoperable – by the Open GeoSpatial Consortium (OGC) and thus often called OGC Web Services (OWS). The most prominent type of map service is the Web Map Service (WMS) that delivers images with already visualised data. There are also other types and which one is most appropriate depends on the underlying data and the use case.

Usually map services are provided by a Spatial Data Infrastructure (SDI). If you want to create your own viewer, chances are that you also need to create a map service. In this case, checkout the Standard Operating Procedures of the O2A SDI, which is already providing a large portion of the map services used in existing viewers.