Map charts enable users to visualize geographic data on responsive and interactive maps. These maps also provide significant control of the way that map points are plotted.
To create a map chart, your query must include at least one dimension that is based on geographic data. If you include measures in your query, the map will represent that data about your locations. For example:
In this example, the Location dimension, which is based on latitude and longitude data, represents the location of each airport. The Max Elevation measure displays elevation information about the highest elevation for each airport on the map, with points color-coded by value.
Limit the precision of latitude and longitude data coordinates to no more than five to six decimal places. If coordinates exceed seven decimal places, the map will not display any data points.
Building an Interactive Map Chart
You can build an interactive map chart by selecting the Map visualization type in the Visualization bar. To create a map chart, your query must include at least one of the following fields:
- A dimension based on latitude and longitude data. This is defined by a LookML developer as a dimension of
- A dimension with a map layer assigned to it. LookML developers can add a built-in map layer or a custom map layer to a dimension using the
- A zip code dimension. Zip code regions are based on the 2010 zip code tabulation areas (ZCTAs). If you are visualizing zip codes, there may not be a one-to-one correspondence between zip codes and the ZCTAs used for map visualizations, so it’s possible that not all points will be visualized in the map.
Once your data is organized, you can use the visualization options for editing interactive charts, as described on this page. Access the visualization options menu by clicking the gear in the upper right corner of the Visualization bar. See below for map chart options. Some of the options listed below may be grayed out or hidden in situations where they would conflict with other settings you have chosen.
Plot Menu Options
The Plot tab allows you to select the way that your location data will be plotted. Each choice will have slightly different formatting options, as appropriate for the plot type. In addition, the Plot options are different depending on whether a map layer is defined in the LookML for your dimension.
|For dimensions that are not associated with a map layer, the following Plot options are supported:||
Zip code dimensions automatically have a US zip code map layer assigned. For other dimensions that have a defined map layer, you will see this set of Plot options:
The Points map visualization will plot each row in the underlying data table as a discrete point on the map.
A location dimension by itself will place points of uniform size and color. Adding a measure to the underlying data table enables the points to be scaled by color or size.
The Automagic Heatmap visualization will display the data in the underlying query as a heatmap grid. It works by dividing the visible map into equal squares, then calculating which values in your data fit into each square. The squares are colored according to a measure that you choose. Zooming this map in or out will prompt Looker to re-calculate the grid, so that the granularity is appropriate to the zoom level.
For this plot type to work properly, you must select both a location dimension and a measure.
The Automagic Heatmap will re-query your data in order to construct the heatmap grid. A location dimension will typically show distinct points with one latitude/longitude coordinate, but while using a heatmap, the dimension changes to the bounding boxes ("Heatmap region from ... to ..") of each square in the grid.
Connect with Lines
The Connect with Lines map visualization takes two fields of
type:location from your query, then connects them together in the visualization. Adding a measure to the query will enable you to add a color scale to the lines.
Connect with Areas
The Connect with Areas map visualization takes one field of
type:location and connects all the points in the order you've sorted them, forming the boundaries of an area on the map. Adding a measure to the query will enable users to format the size and color of the individual location points bounding the area.
For heatmap visualizations, the Heatmap Gridlines option adds a border around each of the gridlines used for the heatmap.
For heatmap visualizations, the Heatmap Opacity settings allows you to specify the opacity of the colors used in the heatmap. Type a number between 0 and 1, where 0 means no color and 1 means totally opaque.
Gridlines on Empty Regions
When the Heatmap Gridlines option is turned on, and you are plotting a dimension that has a defined map_layer_name, you can toggle on Gridlines on Empty Regions to display an outline around the map regions that have no associated data. Below is an example heatmap visualization with Gridlines on Empty Regions turned off (left image) and with it turned on (right image).
Map Menu Options
Map styles clockwise from top left: Light (No Labels), Dark, Traffic (Day), Satellite
Map Style enables users to change the type of background map, and whether or not map labels (like cities and streets) should be displayed. This option features a drop-down menu with a list of choices:
- Light: Subtle, light-colored map designed to provide geographic context while highlighting your data.
- Light (No Labels): Same as Light, except the map omits labels such as city names.
- Dark: Subtle, dark-colored map designed to provide geographic context while highlighting your data.
- Dark (No Labels): Same as Dark, except the map omits labels such as city names.
- Satellite: Map displaying global satellite and aerial imagery.
- Satellite (No Labels): Same as Satellite, except the map omits labels such as city names.
- Streets: General-purpose map that emphasizes legible styling of road and transit networks.
- Outdoors: General-purpose map tailored to hiking, biking, and other outdoor uses.
- Traffic (Day): Light-colored map emphasizing transit networks and roads, including current traffic information.
- Traffic (Night): Dark-colored map emphasizing transit networks and roads, including current traffic information.
Map Position changes the center point and zoom level of the visible map. There are two options to specify this position:
- Fit to Data: Automatically centers and zooms the map such that all the data points of your query are visible.
Custom: Enables you to manually set a Latitude, Longitude, and Zoom Level (higher numbers create a closer zoom level):
If you drag and zoom the map itself to arrive at the view you'd like, these values will automatically be filled in when you choose Custom.
Not available with the Automagic Heatmap plot type
Map Scale Indicator
The Map Scale Indicator enables you to determine whether a map scale will be shown, and, if so, what units you'd like to see:
- Metric (m, km)
- Imperial (ft, mi)
- Metric and Imperial
Allow Panning allows you to determine whether users can reposition the map by dragging it. This feature is allowed by default.
Allow Zooming allows you to decide if a (+/-) button should be displayed in the upper left of the map visualization, allowing users to zoom in and out. This feature is on by default.
Show Full Field Name
Show Full Field Name determines whether to show the view name along with the field name in map tooltips, which are displayed when users click on map data points.
Show Legend lets you determine whether a map legend should be displayed in the lower right of the visualization. The legend shows the color scale you are using, if you've added a measure to your visualization.
The Show Legend option is available for the following Plot options:
Show Region Field in Tooltip
Show Region Field in Tooltip allows you to display the region information in the tooltip of the map. Click on a point in the map to see the name of the region:
If your Looker developer has defined drilling options for the dimension, you can click the region name to drill further into the data:
Tooltips on map charts look and function slightly differently when viewed on dashboards using the new dashboard experience. For more information, see the Viewing Map Charts in the New Dashboard Experience section of this documentation page.
Draw Map Labels Above Data
Draw Map Labels Above Data allows you to display the map's labels above or below the heatmap. This is especially significant with higher heatmap opacity values. If your heatmap is opaque, the labels will not show unless they are displayed above the data:
Points Menu Options
Not available with the Automagic Heatmap plot type
Point types clockwise from top left: Circle, Icon, Both, None
For maps of plot type Points, Lines, and Area, Type specifies the type of point displayed on the map visualization. There are four types of points for map visualizations (depicted above):
The selection you make for point type impacts the formatting options that are available. The screenshot above show the options for a Type of "Both", which includes all of the options.
Enables you to choose an icon to display on all map markers (they cannot be dynamic according to your data).
If you've used a Type of Circle, this setting enables you to set the size of that circle according to the following options:
Proportional to Value: This setting adjusts the relative size of the circles according to measures you've added to your query. When you choose this option you can set a Minimum Radius and Maximum Radius of the circles, which will correspond with the lowest and highest value in your data. You can also toggle between a Linear and Logarithmic scale when the circles are being sized.
Equal to Value: This setting adjust the radius of the circles to the actual measure values in your underyling query. This likely only makes sense if you are plotting distance data; for example, if your measure contained the size of a territory.
Fixed: Enables you to set a fixed radius to apply to all map markers. The default value is 500.
Sets the units that are used in the Radius section to meters or pixels.
Marker Color Value
Enables you to set the color of the map markers in an interactive map. There are two choices:
- Based on Value: Colors will be dynamically assigned to markers based on the values of your underlying query. To configure the colors in the legend for this option, see the Value Colors option.
- Custom: Enables you to set a single color to use for all map markers. The color value can also be formatted as an RGB hex string, such as
#2ca6cd, or as CSS color names, such as
Value Menu Options
The Value menu will disappear if the Marker Color Value for map points chart is set to “Custom”
The Value Colors input box enables you to set the color of map points, or define the range of colors to be used if you are color coding according to a measure.
You can input a list of hex strings, such as
#2ca6cd, or CSS color names, such as
mediumblue. The colors you input first are associated with the lowest values.
When turned on, Quantize Colors changes the color scale from a smooth gradient to only the specific colors you've set.
The image on the left depicts the legend when Quantize Colors is off, and the image on the right depicts the legend when Quantize Colors is turned on:
Reverse Color Scale
When turned on, Reverse Color Scale switches the colors that indicate high and low values on the chart, reversing the color gradient.
The image on the left depicts a chart with low values indicated by green, and high values indicated by red. The image on the right depicts the same chart with Reverse Color Scale turned on:
Minimum Value/Maximum Value
These colors set the minimum and maximum values of the color range. This enables you to color code all points below a certain threshold with the lowest color, and all points above a certain threshold with the highest color.
By default this field is left blank, and the minimum and maximum values applied on the legend are the minimum and maximum values from your query.
Viewing Map Charts in the New Dashboard Experience
When you view map charts in Looker’s new dashboard experience, tooltips function slightly differently than they do when you view map charts as Looks, as Explores, or in legacy dashboard tiles:
In the new dashboard experience, the tooltips appear on hover, rather than on click. Viewers of a dashboard can see content placed in a tooltip with the
html parameter, but if any interactive content is included as part of the
html parameter — such as links — viewers will not be able to click on it.
If you click Explore from Here on a map chart dashboard tile, or if you open the edit window for a map chart tile, you will see the Look and Explore version of the map chart.