diff options
Diffstat (limited to 'platform/darwin/src/MGLHeatmapStyleLayer.h')
| -rw-r--r-- | platform/darwin/src/MGLHeatmapStyleLayer.h | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/platform/darwin/src/MGLHeatmapStyleLayer.h b/platform/darwin/src/MGLHeatmapStyleLayer.h index aa6224a5a0..1cecc30441 100644 --- a/platform/darwin/src/MGLHeatmapStyleLayer.h +++ b/platform/darwin/src/MGLHeatmapStyleLayer.h @@ -7,7 +7,23 @@ NS_ASSUME_NONNULL_BEGIN /** - A heatmap. + An `MGLHeatmapStyleLayer` is a style layer that renders a <a + href="https://en.wikipedia.org/wiki/Heat_map">heatmap</a>. + + A heatmap visualizes the spatial distribution of a large, dense set of point + data, using color to avoid cluttering the map with individual points at low + zoom levels. The points are weighted by an attribute you specify. Use a heatmap + style layer in conjunction with point or point collection features in vector + tiles loaded by an `MGLVectorSource` object or `MGLPointAnnotation`, + `MGLPointFeature`, `MGLPointCollection`, or `MGLPointCollectionFeature` + instances in an `MGLShapeSource` object. + + Consider accompanying a heatmap style layer with an `MGLCircleStyleLayer` or + `MGLSymbolStyleLayer` at high zoom levels. If you are unsure whether the point + data in an `MGLShapeSource` is dense enough to warrant a heatmap, you can + alternatively cluster the source using the `MGLShapeSourceOptionClustered` + option and render the data using an `MGLCircleStyleLayer` or + `MGLSymbolStyleLayer`. You can access an existing heatmap style layer using the `-[MGLStyle layerWithIdentifier:]` method if you know its identifier; @@ -18,6 +34,14 @@ NS_ASSUME_NONNULL_BEGIN ### Example ```swift + let layer = MGLHeatmapStyleLayer(identifier: "earthquake-heat", source: earthquakes) + layer.heatmapWeight = NSExpression(format: "FUNCTION(magnitude, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)", + [0: 0, + 6: 1]) + layer.heatmapIntensity = NSExpression(format: "FUNCTION($zoomLevel, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)", + [0: 1, + 9: 3]) + mapView.style?.addLayer(layer) ``` */ MGL_EXPORT |