MapLibreParticleLab/platform/android/docs/styling/distance-expression.md

Distance Expression

{{ activity_source_note("DistanceExpressionActivity.kt") }}

This example shows how you can modify a style to only show certain features within a certain distance to a point. For this the distance expression is used.

![Screenshot of map where only labels inside some circular area are shown]({{ s3_url("distance_expression_activity.png") }}){ width="400" } {{ openmaptiles_caption() }}

First we add a fill layer and a GeoJSON source.

--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/DistanceExpressionActivity.kt:FillLayer"

Next, we only show features from symbol layers that are less than a certain distance from the point. All symbol layers whose identifier does not start with poi are completely hidden.

--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/DistanceExpressionActivity.kt:distanceExpression"