GaWC - Atlases by Jared Lang

Atlas 1

Basic Atlas: Wrapping Flow Lines Around a 3D Globe

For the first set of visualizations, the research group sought to employ a cartographic concept which uses flow lines to represent the strength of a city's connection to its peers. The most current work done mapping flow lines comes from mapping global internet [1] and phone connections. [2] Lines are used to connect cities, and color or size is used to represent a variable. In this case, the variable is connectivity. The visualizations below adapt concepts from mapping global internet and phone connections to represent Peter Taylor's world city network connections.

Examples

Athens	Amsterdam

for all 62 snapshots and 3D scenes click here

The Method of Creation:

1. We selected the top 123 cities in terms of their global network connectivity and measured the connectivity between each city and the other 122 cities. The top 62 most well connected cities are visualized below.

2. These individual city inter-linkages reflect the overall pattern of global network connectivity (i.e. every city is most connected to either London or New York).

3. ESRI's software, ArcGIS v.8, is used to create three-dimensional visualizations of the raw connectivity values for each city.

4. In order for the maps to be viewed by users, they were exported into Virtual Reality Modeling Language (VRML). Hence, the format of the links posted below. Each city has an individual link.

5. VRML scenes require a VRML Player. If users follow the directions and downloads the free Cosmo Player software, they can view the maps through the web browser on their own computer. The link to the Cosmo Player software is as follows:

Cosmo Player Software: http://ovrt.nist.gov/cosmo/

6. For those users who desire to manipulate the visualizations in a GIS, the Base Layer Shapefiles are included (click here). This includes the background globe, country outlines, and each individual city's point shapefile with connection values included. If the user requires more detailed information, then they can e-mail Jared Lang.

To View the Visualizations:

1. If the user's computer utilizes Microsoft's Windows XP operating system, then the Windows NT version of the Cosmo Player software is the one they need to download.

2. The links below are zip files containing the entire VRML scene and the legend for each city. Images are provided below to give users a snapshot of what the scene looks like. Depending on which cities the user is interested in, they just need to download those zip files to their computer.

3. Once unzipped, all scene files need to stay in the same folder. The scene file at the top will open the entire visualization. The user must make sure their web browser is open before they click to open the scene.

4. When inside the scene, clicking on the globe with the "Seek" tool centers the globe in the scene, and enables the user to use the "rotate" tool to rotate the globe from its center. For reference, an image of the "seek" tool is below.

Example

Understanding the Visualizations:

1. Flow lines connect each city. For example, the London scene shows flow lines from London to the other top 123 cities. Color of the flow lines represents the strength of connectivity.

2. This is a basic legend. The strongest connections are made to stand out with the red lines. The choice of colors for the globe and country outlines was designed to draw out the flow lines.

Basic Legend

An Important Endnote:

While working on these visualizations, the research group realized a crucial flaw in many of the visualizations. Because the research group was attempting to represent such a large dataset, some visualizations became cluttered. Consequently, it may be difficult to fully understand the relationships between some of the cities. The next series of visualizations attempts to address these problems.

If you have any questions about the Atlases, or if you want to obtain the details about how the visualizations were created, you can e-mail Jared Lang, Danny Dorling, or Peter Taylor.

Endnotes

Atlases by Jared Lang - Atlas 1