…or, if you want the clickbait title of this post, “Creating cool Minecraft-type landscapes in Power Map”…
I’m a big fan of Owen Boswarva’s UK open data blog, and yesterday this post on English LiDAR data released by the Environment Agency caught my eye:
http://mapgubbins.tumblr.com/post/131424021480/open-data-release-of-aerial-lidar-data-for
I won’t repeat what he says because there’s nothing I could add to it, but basically this data is a 3D scan of large parts of England at extremely detailed resolutions. You can download the data from this site:
http://environment.data.gov.uk/ds/survey#/download
My first thought after reading this was post was that it should be possible to load this data into Excel (in general) and Power Map (in particular) using Power Query fairly easily. And indeed it was – so in this blog post I’ll show you how.
First of all, here’s a sample of the output. This is a Power Map custom map showing tile SU9090, which shows a section of the M40 motorway and its surroundings near High Wycombe:
Zooming in on an area just below the centre of the above screenshot you can see several distinctively-shaped office buildings, the M40 going across the screen and, on the top right-hand side, a Tesco superstore:
Here’s the same area shown in Bing Maps (http://binged.it/1RkakM7):
Here’s the obligatory video:
How did I do this? The first step is to load the data into the Excel Data Model using Power Query. I created a Power Query function called LoadLiDARData to do this, and you can get a sample workbook with it in from here. There isn’t much to say about the function – it’s not trivial, but not very interesting in itself. To use it, in Excel go to the Power Query tab on the ribbon and open the Workbook Queries pane. To load data from a single .asc file downloaded from the Environment Agency site, right-click to invoke the function and enter the filename (including the full path) of that file. The Power Query Editor window will open but you don’t need to do anything here except click the Close & Load button. I recommend you load the output to the Excel Data Model rather than a table in the worksheet because a single file contains a lot of data!
Next, go to the Insert tab on the Excel ribbon and click the Map button to open Power Map. Then click New Scene\New Custom Map to create a new custom map. You need to make sure that the Min values for the X and Y axis are set to 0, the Max value for X is set to the number of columns and the Max value for Y is set to the number of rows in the data you’re working with. Also, check the Flip Axis button for the Y axis.
Then, on the right-hand side of the screen check the ColumnNumber and RowNumber boxes and set them to be the X Coordinate and Y Coordinate respectively:
Click the Next button, then check Height to use as the height of a bar graph:
Finally – and this is important – go to Settings and adjust the Thickness property appropriately. If you don’t do this you won’t be able to pick out any detail; I have used 18% as a good starting setting. Ticking the Lock current scale box is also a good idea, so that when you zoom in the bars don’t disappear.
This is no more than a proof-of-concept. I’ve only tested my code with a very limited amount of data, and there are a lot of obvious improvements that could be made: for a start, it would be good to convert the grid co-ordinates used to latitude and longitude so that this data can be used with the maps in Power Map. I could also imagine some really useful applications for this, such as combining a map like this with snowfall data and creating an animation showing where snow falls over a landscape during the winter.
Of course a dedicated tool will do a much better job of visualising this data than Excel, but if you have the right edition of Excel 2013 then you can get everything you need to do this for free and in Excel 2016 Power Query and Power Map (as Get & Transform and 3D Maps) are available out-of-the-box. It also sounds like Power Map will be integrated with Power BI at some point too:
UPDATE: Here’s a video of another tour I created using LiDAR data, showing Waterloo Station, the Houses of Parliament and Westminster Abbey in central London
