Month: April 2014

Choosing A Mapping Tool in the SQL Server BI Stack

With the addition of the Power BI suite to the SQL Server BI stack, there are now 3 main options for creating data-driven maps. I have been working on a presentation to help you choose which mapping tool is appropriate for your needs on a given project. I gave the presentation for the first time in SQL Saturday Chicago, and I’ll be presenting it again at the first SQL Saturday – BA Edition in Dallas on May 3. I’ll share the highlights of the information I provide in my presentation in this blog post, and you’ll just have to attend a SQL Saturday where I’m speaking to get the rest of the details.

There are 3 main tools between Excel, SQL Server, and SharePoint that can visualize data on maps:

  • Power View
  • Power Maps
  • Reporting Services

There are also a few apps for Excel 2013 that create maps (Bing Maps, Geographic Heat Maps). I’ll explain the Excel apps in a later blog post, and focus on the more mainstream tools for today. Although you can make maps with each of these tools, there are some significant differences in features, time to delivery, and system requirements for each of these tools. The image below summarizes the pros and cons for each of these tools.

Maps OverviewPower View is the easiest to use, but it has the most limited features. The drag and drop interface allows you to build a map in a matter of minutes. But this ease of use comes at the price of limited customization. The only type of graph you get on a map is a bubble chart, which turns into pie charts if you add a category. You can only build one layer of data on your map. Also, fonts and colors are limited to the themes available within Power View. Power View offers great interactivity and cross-filtering capabilities. You can set up your map so it drills down from country to state to city. You can use slicers and other graphs to filter and highlight data on a map. An example of using a map to filter a related table in Power View can be found here. Power View reports are usually visually appealing and lend themselves well for presentations. And if you are using Power View inside of SharePoint, you can export your Power View to a PowerPoint presentation and retain interactivity.

Power Map’s strongest features are a time axis that enables you to watch trends over time, the ability to show multiple layers at once, and the storytelling capabilities that come from scenes and tours. Power Maps have more choices for graphs, including columns, bubbles, heat maps, and region shading. But there is no drill-down capability to see an increased level of detail. Power Map also lacks the ability to filter data.  For example, if you have sales data for three products and you only want to see sales for Product A, Power Map doesn’t offer a way to filter to just Product A. This means that you may have to add some DAX calculations to your Power Pivot model to facilitate your map creation. DAX has its own learning curve, so this increases the time required to build the map if you have to learn DAX and alter your Power Pivot model first. Update: As of Sept  2014 you now have the ability to filter your data in a Power Map. The great thing about Office365 is that you can get monthly updates.  The inconvenient thing about that is I have to go back and update blog posts when this happens. Power Map can facilitate great storytelling with data through the use of scenes and tours. You can look at a particular geography and time period in each scene and combine scenes into a tour, then you can share that tour to take users on your journey to gain insight.

Although Reporting Services isn’t getting much love from Microsoft’s marketing or engineering groups, it is still a very viable option for creating maps. While SSRS can require more technical expertise and time to deliver a finished product, it allows the most customization of the three tools and offers subscriptions (time-based and data driven) and multiple rendering and export formats. It also allows custom shapes, so you aren’t limited to whatever the Bing Maps API can do. This helps with custom geographical regions within a company or its customers. It also means you can map more than just points on a globe; you can map floor plans and other shapes you can capture with SQL Server spatial data types. Where Power Map and Power View don’t necessarily require a lot of infrastructure to share a report, SSRS reports require a Report Server or SharePoint Server to make a report available to users.

I’ve developed the following high-level categories to be used to evaluate the appropriateness of each tool for your map.

Maps Eval CriteriaI used these evaluation categories to summarize my findings for each tool in the table below. You’ll notice that I split Power View into Power View for Excel and Power View for SharePoint. This is because these two different development environments have some different system requirements, data sources, and methods of consumption for the resulting Power View report. Although there are two different modes of Reporting Services (Native and SharePoint Integrated), this difference only affects system requirements so SSRS was kept as a single category.

Maps SummaryFor system requirements, note that Power View works with Excel 2013 Professional Plus and O365 Pro Plus and a few other versions, but you must have an Office 365 Pro Plus subscription to get the GA version of Power Map.

Although the Power Map release notes state that you can use it with a 32-bit processor, large amounts of data or graphics intensive map layers can slow the computer to halt or cause Excel to crash. If you can help it, it’s best to have a 64-bit computer for Power Map development or consumption in Excel.

You’ll notice that the list of data sources for SSRS is fairly long compared to the other development environments, but don’t let that mislead you. I’m just listing direct data sources. Although Power Pivot only takes up one line, it can connect to a multitude of data sources, and Power Query extends those options even further. SSAS Tabular also has many options for data sources.

Also, be aware that bubble sizing in Power View for small values can be misleading. This issue is compounded by the fact that turning on data labels for a Power View map only labels the location and not the amount related to the size of the bubble.

In my presentation at SQL Saturday Chicago, one of the attendees expressed the opinion that Power Maps tend to be very busy and it’s difficult to tell where to look when you first encounter one.  I don’t disagree with that, so I’ll throw in the warning that it can be very easy to make a Power Map that is visually appealing but doesn’t provide any insight into your data. I think there are some good use cases where Power Map is the best tool to deliver insight, but not every map needs a time axis and multiple layers/multiple graph types. Another limitation of Power Map is that is can only be opened from the Excel file that contains it (there’s no way to view it in a web browser). While I expect that to change in the future, this is the current state today. Outside of exporting a tour to video, the development environment and the viewing environment are one and the same. To create a new Power Map or insert an existing Power Map, you must go to the Insert tab in Excel and choose Map. This will open the Power Map window where you can view and update your map.

I also want to point out that SSRS is the only one of the three tools that can make use of SQL Server spatial data types. If you would like to learn more about spatial data types in SQL Server, Hope Foley has a great presentation on the subject and has her slides and scripts posted on her blog. Jason Thomas has some good blog posts on SSRS maps.