FeatureCollection

Last Updated On 2021-07-16

A FeatureCollection contains one or more map features as a group. Any events fired on a feature in the collection will also trigger the corresponding event on the collection object. FeatureCollections can be loaded from external resources as a means of populating a Map with content.

Properties

You can set the below properties in the UI part of the builder.

FeaturesFromGeoJSON - it's a textArea value which is set to blank by default.
HeihMargin - it's a four value which is set to 0,0,0,0 by default.
HeihPadding - it's a four value which is set to 0,0,0,0 by default.
MarginBottom - it's a non negative float value which is set to 0 by default.
MarginLeft - it's a non negative float value which is set to 0 by default.
MarginRight - it's a non negative float value which is set to 0 by default.
MarginTop - it's a non negative float value which is set to 0 by default.
PaddingBottom - it's a non negative float value which is set to 0 by default.
PaddingLeft - it's a non negative float value which is set to 0 by default.
PaddingRight - it's a non negative float value which is set to 0 by default.
PaddingTop - it's a non negative float value which is set to 0 by default.
Source - it's a geojson type value which is set to blank by default.
Visible - it's a visibility value which is set to true by default.

Block Properties

You can set the below blocks properties in the blocks section of the builder.

Features

The list of features placed on this FeatureCollection. This list also includes any features created by calls to FeatureFromDescription

FeaturesFromGeoJSON

Loads a collection of features from the given string. If the string is not valid GeoJSON, the ErrorLoadingFeatureCollection error will be run with url = .

Height

Specifies the vertical height of the FeatureCollection, measured in pixels.

HeightPercent

Specifies the vertical height of the FeatureCollection as a percentage of the height of the Screen.

MarginBottom

Property for MarginBottom

MarginLeft

Property for MarginLeft

MarginRight

Property for MarginRight

MarginTop

Property for MarginTop

PaddingBottom

Property for PaddingBottom

PaddingLeft

Property for PaddingLeft

PaddingRight

Property for PaddingRight

PaddingTop

Property for PaddingTop

Source

Specifies the source URL used to populate the feature collection. If the feature collection was not loaded from a URL, this will be the empty string.

Visible

Specifies whether the FeatureCollection should be visible on the screen. Value is true if the FeatureCollection is showing and false if hidden.

Width

Specifies the horizontal width of the FeatureCollection, measured in pixels.

WidthPercent

Specifies the horizontal width of the FeatureCollection as a percentage of the width of the Screen.

Methods

You can set the below method blocks in the blocks section of the builder.

FeatureFromDescription

Converts a feature description into an App Inventor map feature. Points are converted into

LoadFromURL

Load a feature collection in GeoJSON format from the given url. On success, the event GotFeatures will be raised with the given url and a list of the features parsed from the GeoJSON as a list of (key, value) pairs. On failure, the LoadError event will be raised with any applicable HTTP response code and error message.

Events

You can set the below event blocks in the blocks section of the builder.

FeatureClick

The user clicked on a map feature.

FeatureDrag

The user dragged a map feature.

FeatureLongClick

The user long-pressed on a map feature.

FeatureStartDrag

The user started dragging a map feature.

FeatureStopDrag

The user stopped dragging a map feature.

GotFeatures

A GeoJSON document was successfully read from url. The features specified in the document are provided as a list in features.

LoadError

An error was encountered while processing a GeoJSON document at the given url. The responseCode parameter will contain an HTTP status code and the errorMessage parameter will contain a detailed error message.