Greenland

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About

Greenland is a client-side tool to render quality-aware geospatial data, implemented as OpenLayers-based webpage. It is based on work originally developed within the UncertWeb project known as "the visualization client".

Demo

The current version of Greenland is available here: http://geoviqua.dev.52north.org/greenland/. Take a look at the examples to see what you can do with it!

Screenshots

The following screenshots present some of the features of greenland such as visualisation using glyphs or multiple maps, and uncertainty visualisation with whitening or confidence triangles. Take a look at the examples page for more documentation and an extensive showcase including animation, vector data, and client-side calculated contouring.

Who is it for?

Greenland is a tool for explorative data analysis with a special focus on visualisation of data uncertainty (based on the UncertWeb project) and data quality (relation to the GeoViQua project). It targets expert users (such as scientists, domain experts and decision makers) who want to interactively analyse their own dataset that is available through web services and/or combine it with online datasets - it does not target at the general public. Greenland is designed to help users judge the uncertainty on datasets by providing them with an overview of the uncertainty spatially and temporally by applying new but also established visualisation methods side-by-side. This software provides information, but is not really there specifically for decision making - more for getting an understanding of the data at hand.

For example, a scientist can use it to "get a feeling" for the data, which typically is a central value and dispersion estimate, and understand how this varies in space and time and an idea of the magnitude and patterns.

Help and Support

Please see the Help and Support page: GreenlandHelp

Using Greenland

Download

Greenland is available as a daily build (binary download) in the 52°North build server: http://build.dev.52north.org/jenkins/job/Greenland/lastSuccessfulBuild/artifact/target/.

Download the *.zip file for the standalone version and use the .war file for deployment of Greenland in a servlet container (e.g. Tomcat) or as a Portlet (e.g. for Liferay).

Source code repository: https://github.com/52North/Greenland

Installation

Greenland can run as a standalone Javascript application, as a webapp in a servlet container (such as Tomcat) and as a Portlet in a portal server.

Standalone Local

Simply download the zip file (see above), unzip to a local folder and open index.html in a browser. There are some limitations using to this method:

• Data servers must support CORS (applies for WMS and THREDDS resources)
• Help and about pop-ups usually do not work because of browser restrictions
• Client-side rendering of WMS-Q resources may fail because of browser restrictions

Webapp

Download the latest web archive file (see above) and deploy it to your servlet container. That's it.

Portlet

Download the latest web archive file (see above) and deploy it to your portal container. The Greenland Portlet is automatically registered in your portal engine. Note that Greenland uses mechanisms specific to Liferay portal provider in order to include external script resources.

Features

Get a first hand look at the features based on the GreenlandExamples page.

General

• Time- and quality-aware visualizations
• User-defined number of adjacent maps
  • Allows synchronized interactions
• Intuitive options for ordering and managing layers between and within maps(drag and drop)
• Analysis functions
  • Feature info for raster and vector data
  • Layer swiping
• Adding of data sources at runtime
• Permalink Generation
• Various base maps
• Support for custom WMS

Visualization of NetCDF data

• Understands uncertainties encoded in NetCDF data using a custom server-side component providing basic visualizations
• Supports ncWMS(-Q) as NetCDF data source, allowing various quality-aware visualizations directly rendered within the web client
  • Contouring
  • Mapping of uncertainty in color schemes (e.g. whitening)
  • Uncertainty used to depict pictorial symbols from raster data (glyphs)
  • Visualization of confidence interval bounds in a single map (confidence triangles)
• Customizable scale ranges and color schemes

Visualization of geographic features

• Support for O&M/O&M2 encoded vector data (XML and JSON notation)
  • Points, lines, polygons
• Support for encoded uncertainties using UncertML
  • Detail views of encoded distributions and realizations
  • Ability to compare features
• Evaluation of custom user-defined functions
  • Combination of different encoded values
  • Eases analysis of data (e.g. applying log-function on the fly)
• Various styling options of features (shape, size, color-schemes, etc.)
• Animations

Development

Development is documented here: GreenlandDevelopmentDocumentation

Important input for the next developments is this heuristic evaluation of Greenland's usability:

• Greenland_Heuristic_Evaluation.pdf
• Greenland_Heuristic_Evaluation.docx

Use Cases and Applications, Ideas

• Visualisation of community driven water depth maps with OpenSeaMap: OpenSeaMapDepthMap

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This work is licensed under a Creative Commons Attribution 3.0 Unported License.