Engine Works
Under the hood of Alteryx: tips, tricks and how-tos.
What is .Grd and .Grc in Alteryx?
Alteryx 7.0 will be supporting .Grd and .Grc files. This file format is a specific type of grid (raster) file which is used mostly in the Telecommunications space for viewing cell tower projection. The grid cells mostly represent decibel strength which normally ranges between -200 to zero. The higher value is the stronger signal strength. These values can be unique to the company so as a best practice make sure to view your data snippet values before specifying the cut off values.
Looking at the recent iPhone debate around signal strength which arose from the ‘antennagate’ issue from the release of the iPhone 4 explains the logic behind signal strength as they relate the Bar strength visible on your cell phone. Zero bars being the lowest and 5 being the highest.
The below image shows the iPhone 4 with its Bars and then the software updated iPhone 4 Bars.
Research sourced from:
http://www.anandtech.com/show/3821/iphone-4-redux-analyzing-apples-ios-41-signal-fix
Using Alteryx and the new .Grd file input it supports I mapped the projection of Cell Tower Coverage around Boulder Colorado to represent the Cut off values shown with the updated software on the iPhone 4. Cut-off values are (-121,-107,-98,-87,-76,-51)
You can see from the cut-offs where you would expect to see the correlating bars of strength. Green representing less than 1 bar and purple being 5 bars.
Alteryx is then able to analyze this data read in as .Grd and .Grc for further improvements of cell tower projection coverage based off of the many available demographics. The projection can also be analyzed to locate weak coverage and where to enhance projection or add booster locations for poorly served households.
Below is the original iPhone 4’s Bar strength cut-offs before the software upgrade: (-113,-107,-103,-101, -91, -51) Notice how much bigger the 5 bars (purple) are! Clearly the representation is overstated.
The graph below shows the results of the analysis in comparison to before and after the update:
The grid cells in Alteryx can be output as individual cells or grouped into a specific cutoff range. In a similar manner .Grc files, grid cell contours can be grouped into classes to show specific cell tower’s individual projections. The below image demonstrates this projection.
These too can be output as individual cells. The above result shows the projection of the cell tower per class. It is easy to see where weak spots lie and how to better arrange cell tower projection angles to achieve the best reception possible.
The flexibility Alteryx gives to analyze this data format is unique to the product. I attached one more image of a demographic analysis based off of cell tower projection created in Alteryx; this will be available as a wizard sample with Alteryx 7.0 and the new data install for Telco. The analysis covers the population covered by the projection. The report can be used to investigate under covered populations.
