Map View
Nodes in the data can be displayed in a global, geographic map using Map View if geo-coordinates are included in the node file. The map allows you to zoom to the geolocation indicated in the node list. Although latitude and longitude give you the most precise location, zip codes and other geopolitical demarcations (counties, and states) are also rendered on the map if latitude longitude data is unavailable. MicrobeTrace uses Stamen.com for base map tiles, which in turn uses openstreetmaps.com for some other libraries. Use the various settings as described below. The settings dialog box has four tabs: Data, Components, Nodes, and Links.
In this example, we would like to visualize data by latitude and longitude. NOTE: The map display is hierarchical, so if your data set has all the data columns listed below, and you select multiple properties, the map displayed will default to the highest available level of geographic precision. Please ensure you select only the variable that works best for your data set, and leave the others as None.
Selecting Components will enable making changes to the actual network that will be displayed, including nodes and links. You can also choose whether to would like to use Map View while online or offline. This option will determine which features are displayed. When offline, you can choose to show or hide countries, states and counties. When online, you can choose to display either base map or satellite view layers that are not available offline in MicrobeTrace. If you select these options, MicrobeTrace will download the base map and satellite geographic data (called tiles) from the internet, which are similar to the Google map features. MicrobeTrace also has the capability to load GeoJSON files if you have generated data with specific location information in that file format. To add GeoJSON files into MicrobeTrace, select User-Provided, browse to the location on your computer where the file is stored, and load the file.
Select Nodes to change the appearance of nodes on the map. Nodes can be colored by any variable in your node file. Selecting Color Options opens up the Global Settings menu, and you can customize the Style settings, background, etc. as in other views. The transparency and jitter speed of the nodes are changed using the respective slider bars. *PLEASE NOTE: In many datasets, there can be many nodes that share the same geographic co-ordinates causing a very high node density in the map such that these nodes appear as a single large dot. In order to separate nodes with the same geographic coordinates, use the jitter slider bar to increase the jitter level to separate or jitter the nodes so they are visible. Use Tooltip to change which variables are displayed when the mouse pointer is placed (“hovers”) over a node. For example, if you choose ID from the Tooltip drop-down menu, the node ID will be displayed when the mouse pointer is over that node.
Select Links to change the link settings. The features are identical to those in the Node tab. You can adjust color, transparency and tooltip settings.
The image below shows the map with nodes colored by risk factor, and links hidden. When viewing a map, the scroll bar on your mouse can be used to pan around or zoom in and out. By default, the map is zoomed out, and you see a circle with a number that represents the number of nodes. When you zoom in, the nodes pop out to form smaller, more discrete groups. Individual or multiple nodes can be selected or de-selected by using the mouse pointer. These selections will propagate to the Network and Table Views. This enables tracking of particular individuals between multiple visualization windows. As with other views, map images can be exported and saved as .png, .svg, or .jpg image files.
MicrobeTrace contains a small dataset of useful geographic data. This enables it to plot data points on maps, even if the location information is generic and imprecise (e.g. US State).
MicrobeTrace's geospatial data catalog includes:
- Countries (Boundaries and Centroids)
- US States (Boundaries and Centroids)
- US Counties (Boundaries and Centroids)
- Zipcodes (Centroids only)
- Census Tracts (Centroids only)