Filled Map in Power BI

A filled map, also called a choropleth map, shades entire geographic areas, such as countries, states, or postal codes, based on a data value. The darker or more saturated the shading, the higher the value for that area. It is built to answer one question at a glance. Where is this number highest, and where is it lowest, across a region.

Filled Map Compared to Bubble Map

Power BI offers two closely related map visuals, and the difference is what they plot. A filled map shades whole areas and boundaries, so it fits data that is naturally tied to a defined region, such as sales by state or population by country. A bubble map plots specific points instead, using dot size and color to represent a value at an exact location, such as individual store locations or event coordinates. If your data describes a region as a whole, use a filled map. If it describes individual points within a region, use a bubble map.

Getting Your Location Data Right

A filled map needs a field that names a real geographic area, such as country, state, city, or postal code. Power BI sends that field to Bing Maps to look up the boundary shape for each value, a process called geocoding, so the accuracy of your map depends entirely on how clearly that field identifies a real place.

• Watch for ambiguous names. A city name like Paris can mean Paris, France, or Paris, Texas, and Bing has no way to know which one you mean from the name alone.
• Set the Data Category on your location field, in the data view, to tell Power BI explicitly what kind of place it is, such as Country or State. This alone resolves most ambiguous location problems.
• If ambiguity still shows up, combine columns, such as city and state together, into one field so the value passed to Bing is specific enough to resolve correctly.
• Filled maps plot areas, not points, so latitude and longitude are not used here even if your dataset has them. Save those fields for a bubble map instead.

Building a Filled Map

In the Visualizations pane, click the Filled Map icon. This adds an empty filled map visual to the report canvas.

Drag your geographic field, such as country, state, or city, into the Location section. Power BI geocodes each value and shades the matching area on the map.

Drag the number you want to measure, such as sales or profit, into the Color saturation section. This is what decides how light or dark each area’s shading is.

You can also add a field to Legend if you want a categorical split rather than a shaded gradient, and a field to Tooltips so hovering over any area shows extra detail, such as exact profit figures for that state.

Choosing the Right Color Scaling

Click the Format icon to open the Format pane, then look under Data colors. For a single measure, Power BI defaults to a gradient between a minimum and maximum color, light for low values and dark for high values, which works well for continuous data such as sales or population. If your data is categorical instead, such as region type or status, use the Legend field to assign a distinct color per category rather than a gradient, since a gradient implies an order that categorical data does not actually have.

When to Use a Filled Map?

• Your data is naturally tied to a defined region, such as country, state, or postal code, rather than individual points.
• You want to spot broad geographic patterns at a glance, such as which regions are strongest or weakest.
• Your regions are reasonably standardized in size and shape, since a choropleth reads best when comparing similar kinds of areas to each other.

Common Mistakes to Avoid

• Shading by raw totals instead of a rate. A state with a larger population will almost always show a higher raw count than a smaller state, regardless of actual performance. Shading by a rate, such as sales per capita or profit margin, tells a fairer story than shading by the total alone.
• Leaving ambiguous location names uncorrected. If a value on your map lands in the wrong country or state, check the Data Category setting on that field before assuming the data itself is wrong.
• Using a color gradient for categorical data. A gradient visually implies more, less, or in between. If your categories do not actually have that kind of order, a gradient will mislead the reader even if the underlying data is correct.
• Comparing very differently sized regions without context. A large, sparsely populated area can visually dominate a map next to a small, dense one, even if the smaller area matters more to your analysis.

A Note on Where This Visual Is Heading

Microsoft has been encouraging a move toward the newer Azure Maps visual, and existing filled maps may eventually be prompted to upgrade. The steps above still apply to the classic filled map available today, but it is worth keeping an eye on this if you are building reports meant to stay unchanged for a long time.

That covers building, formatting, and choosing a filled map in Power BI. To keep building out your report with other map types, explore Prwatech’s Power BI training program, which includes placement assistance.