Latitude/Longitude Support
Cognos Analytics R9 adds latitude/longitude support to maps in dashboards. This is much like the R8 support for latitude/longitude support in report maps allowing geocoded data to be displayed:
In our example, businesses in Hawaii are shown as points located by latitude and longitude with revenue driving the color and Profit driving the size of the points.
As with the Regions and Points layers, the Latitude/Longitude layer has a series of data slots to drop items into:
Tooltips
Tooltips are a little different between report and dashboard maps in this release. Maps in reports do not display the latitude/longitude in the tooltips by default but dashboards currently do; this will be changed to match report maps in a future release.
Latitude/Longitude Encoding
While there are several ways to store latitude/longitude, Cognos Analytics requires using a WGS 84 / World Geodetic System (WGS) encoding stored as numeric data items.
WGS 84 simply means latitudes between -90 and +90 degrees and longitudes between -180 and +180 degrees suitable for use on a Web Mercator map. An example of such a location is the White House in Washington DC located at latitude 38.897957, and longitude -77.036560.
Other formats such as degrees, minutes, second and decimal seconds for example 38° 53' 52.6452'' N, 77° 2' 11.6160'' W are not supported, nor are other X, Y coordinates systems. In such cases, the data would need to be converted to WGS 84 for use in Cognos Analytics.
Errors and Null Island
As part of our error checking, we determine if the latitude values in the data fall between -90 and +90 and longitudes between -180 and +180. Any values outside of these ranges cannot be mapped as they fall outside of the coordinate system. Rather than simply not mapping that data, we replace the query values with latitude 0 and longitude 0 which allows those data points to map allowing you to detect the error.
The 0, 0 location is found just off the coast of Africa in the Gulf of Guinea as show here:
As there is no actual land mass there, this location is somewhat humorously referred to as "Null Island," and is commonly used by mapping systems to display out of bounds data. If you ever see data mapped here, it’s probably in error.
The likeliest cause of such an error is putting the latitude and longitude data items into the opposite data slots when defining the map.
Geocoding
As odd as it sounds, mapping systems cannot normally directly use addresses for locations. Rather, the mapping systems need to have the address converted to an latitude/longitude which can be mapped.
The process of converting an address to a latitude/longitude location is referred to as geocoding. Companies provide geocoding as a paid service. For example, the address of the White House “1600 Pennsylvania Ave NW, Washington, DC 20500” would be passed to a geocode service which would return the latitude 38.897957, and longitude -77.036560. These values are then stored into the RDBMS for use with Cognos Analytics.
Cognos Analytics does not provide geocoding; your data must be geocoded before being used within Cognos Analytics.
Dashboard Hide/Show Layers
Dashboard maps now provide the ability to hide/show layers using the
control found in the top left corner of the map. Here the latitude/longitude layer has been toggled off at the right to allow the user to focus on the points layer:
Note: For simplicity, the legends have been excluded in these images.
Conclusion
We continue to extend Cognos Analytics geospatial capabilities to provide a comprehensive analytics capability.
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