Add a dataset to a map

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This page shows you how to add a dataset to a map, and apply styling.

Prerequisites

Before proceeding, you should have a map ID and map style, and a dataset ID.

• Create a map ID and map style

• Create and upload a dataset

  Note: You need the ID of your dataset to initialize your app.

Associate a dataset ID with a map style

To style the features of a dataset, you apply a style function to the dataset feature layer of a map. The dataset feature layer is created when you associate a dataset with a map style.

Take the following steps to associate your dataset with the map style you're using:

1. In the Google Cloud Console, go to the Datasets page.
2. Click the name of the dataset. The Dataset details page appears.
3. Click the Preview tab.
4. In the Associated map styles section, click ADD MAP STYLE.
   
5. Click the checkbox(es) for the Map Style(s) to associate and then click SAVE.

Caution: Rendering multiple datasets on a map can affect performance depending on the size and number of datasets.

Apply styles to the dataset

To style a feature of the dataset layer, use a styling closure that accepts a GMSDatasetFeature and returns a GMSFeatureStyle to define style attributes. Then set the style property to a styling closure, which contains styling logic.

The styling closure is required to be deterministic and return consistent results when it is applied. If any styling specifications of any feature are changed, the style must be applied again.

Set stroke, fill, and point radius

When styling a feature in the style factory function, you can set the:

• Stroke color and opacity of the border as defined by the UIColor class. The default value is transparent (UIColor.clearColor).

• Stroke width of the border in screen pixels. The default value is 2.

• Fill color and opacity as defined by the UIColor class. The default value is transparent (UIColor.clearColor).

• Point radius of a point feature between 0 and 128 pixels.

Note: If you want a feature to be invisible, return nil from the style function for that feature.

Use simple style rules

The simplest way to style features is to define constant style attributes such as color, opacity, and line width. Apply feature style options directly to a dataset feature layer, or use them in conjunction with custom styling.

Swift

let mapView = GMSMapView(frame: .zero, mapID: GMSMapID(identifier: "YOUR_MAP_ID"), camera: GMSCameraPosition(latitude: 40.7, longitude: -74.0, zoom: 12))

let layer = mapView.datasetFeatureLayer(of: "YOUR_DATASET_ID")

// Define a style with green fill and stroke.
// Apply the style to all features in the dataset.
layer.style = { feature in
    let style = MutableFeatureStyle()
    style.fillColor = .green.withAlphaComponent(0.1)
    style.strokeColor = .green
    style.strokeWidth = 2.0
    return style
}

Objective-C

GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero mapID:[GMSMapID mapIDWithIdentifier:@"MAP_ID"] camera:[GMSCameraPosition cameraWithLatitude: 40.7 longitude: -74.0 zoom:12]];

GMSDatasetFeatureLayer *layer = [mapView datasetFeatureLayerOfDatasetID:@"YOUR_DATASET_ID"];

// Define a style with green fill and stroke.
// Apply the style to all features in the dataset.
layer.style = ^(GMSDatasetFeature *feature) {
    GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
    style.fillColor = [[UIColor greenColor] colorWithAlphaComponent:0.1];
    style.strokeColor = [UIColor greenColor];
    style.strokeWidth = 2.0;
    return style;
};

Use declarative style rules

You can set style rules declaratively based on an attribute of the feature, and apply them across your entire dataset. You can return nil from your feature style function, for example if you want a subset of features to remain invisible.

For example, use the GMSDatasetFeature.datasetAttributes to return the value of a dataset attribute for a feature. You can then customize styling of the feature based on its attributes.

This example determines the value of the "highlightColor" attribute of each feature of a dataset to control the styling:

Swift

layer.style = { feature in
    var attributeColor: String = feature.datasetAttributes["highlightColor"]
    // Conditionalize styling based on the value of the "highlightColor" attribute.
    ...
}

Objective-C

// Apply the style to a single dataset feature.
layer.style = ^(GMSDatasetFeature *feature) {
    NSString *attributeColor = feature.datasetAttributes[@"highlightColor"];
    // Conditionalize styling based on the value of the "highlightColor" attribute.
    ...
};

Remove styling from a layer

To remove styling from a layer, set the style to null:

Swift

layer.style = nil

Objective-C

layer.style = nil;

You can also return nil from your feature style function, for example if you want a subset of features to remain invisible.