Map Viewer allows you to explore data in various ways through a variety of smart mapping styles. When you style map layers in Map Viewer, the nature of the data determines the default styling options. You can experiment with color ramps, line weights, transparency, symbols, and other graphic elements, and see your choices reflected immediately on the map.
To see where features are located and how they are distributed geographically, use the Location (single symbol) style. If you are mapping point features, you can also use the Heat Map style.
Location (single symbol)
Drawing data using a single symbol gives you a sense of how features are distributed—whether they're clustered or dispersed—and may reveal hidden patterns. For example, when mapping city service requests in Miami, Florida, you can see a pattern of the majority of calls originating in the downtown business district.
To style location data using a single symbol, do the following:
- Follow the first four steps of Apply a style.
- In the Styles pane, click the Location (single symbol) style if necessary and click Style options.
- Optionally, do any of the following:
- Click a symbol under Symbol style to change the symbol, and specify the symbol settings. For more information, see Use style options.
- Click a symbol under Symbol style to change the transparency for the overall layer, and in the Fill transparency section, drag the slider to the left (less transparent) or the right (more transparent).
- Click Transparency by attribute in the Style options pane to adjust the transparency of locations per feature, and specify the transparency settings. You can only use this option if you have numeric or date data associated with your locations. For example, if the layer contains income data, you can adjust the transparency of each location proportional to its income.
- Click Rotation by attribute if you are mapping point symbols that have numeric information attached to the points—for example, the direction the wind is blowing—and specify the rotation settings.
- In the Styles pane, click Done.
Heat Map
You can use heat maps when mapping the location of point features. Heat maps are useful when many of the points on the map are close together or overlapping, making it difficult to distinguish between features. They are effective for displaying layers that contain a large number of points. For example, you can use a heat map to show clusters of white shark locations near New Zealand.
Heat maps use the points in the layer to calculate and display the relative density of points on the map as smoothly varying sets of colors ranging from cool (low density of points) to hot (many points). Avoid heat maps if you have only a few point features; instead, map the actual points.
Tip:
If the data contains numeric attribute data, the heat map can weight this data to calculate the optimal display. Choose an attribute field with numeric data to take advantage of weighted features. Strings and other nonnumeric data are not weighted. The attribute field name appears in the heat map options pane when it is being used for weighting.
For recommendations on applying heat maps to high-density datasets, see Best practices for visualizing high-density data.
To use a heat map to style point data, do the following:
- Follow the first four steps of Apply a style.
- In the Styles pane, click the Heat Map style and click Style options.
- Optionally, do any of the following:
- Click the ramp under Symbol style and choose a different color ramp. For more information, see Use style options. You can also click Reverse ramp colors to change the direction of the colors in the ramp.
- Adjust the position of the two handles on the color ramp slider to change how the colors are applied to the density surface.
- Adjust the Area of influence slider to make the clusters larger and smoother or smaller and more distinct.
- In the Style options pane, click Done when you are finished customizing the style or click Cancel to go back to the Styles pane without saving your choices.
- In the Styles pane, click Done.