Here’s something with no practical use whatsoever. Today, after I finished writing the first draft of the chapter on M of my upcoming Power Query book , I got thinking about how Power View and Power Map get all the attention because of all the eye-catching demos you can create with them. And then I thought – why bother spending time finding real data for these demos when you can generate artificial data in Power Query to create patterns? So I got to work… As you probably know, you can create animated charts in Power Map so long as you have date-based data. I therefore created a function in Power Query to draw a circle as a series of points on a graph where each point is associated with a date; I also added data for height and colour for each point. Here’s the function definition: let //declare function to draw a circle CircleFunction = (CircleRadius as number, StartDate as date , Reverse as logical) = let //set the radius radius = CircleRadius, //create a list of numbers from 0 to 359 anglelist = List.Numbers(0, 359, 1), //function to convert degrees to radians radians = (a) = (a * 2 * Number.PI)/360, //create a list of 360 dates starting from the start date unordereddatelist = List.Dates(StartDate, 360,#duration(1,0,0,0)), //reverse the list of dates if the Reverse parameter is True datelist = if Reverse then List.Reverse(unordereddatelist) else unordereddatelist, //generate the list of points on the graph, one for each angle and date positionlist = List.Transform(anglelist, each {_, datelist{_}, Number.Cos(radians(_)) * radius, Number.Sin(radians(_)) * radius, Date . Month (datelist{_}), Number.Abs(Number.Cos(radians(_)))*10}), //convert the list of points to a table outputtable = Table .FromRows(positionlist, {"Angle", " Date ", "x", "y", "Colour", " Size "}), //set data types ChangedType = Table .TransformColumnTypes(outputtable, {{"Angle", type number}, {" Date ", type date }, {"x", type number}, {"y", type number}, {"Colour", type number}, {" Size ", type number}}) in ChangedType in CircleFunction I then created another Power Query query to call this function 30 times to create 30 circles with different radiuses: let //generate a list of numbers from 0 to 29 circlelist = {0..29}, //generate a list of 30 dates starting on 1 January 2014 datelist = List.Dates(# date (2014,1,1), 30,#duration(1,0,0,0)), //call the Circle() function 30 times tablelist = List.Transform(circlelist, each Circle(_+5, datelist{_}, Number.Mod(_,2)=0)), //combine the resulting tables into a single table positionlist = Table .Combine(tablelist) in positionlist And here’s the result of the query plotted on a map using Power Map: Pretty, isn’t it? You can download the workbook with the Power Query query and the Power Map tour here .
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