Map

Definition

A two-dimensional container that renders map tiles in the background and allows for multiple Marker elements to identify points on the map. Map tiles are supplied by OpenStreetMap contributors and the the United States Geological Survey.

The Map component provides three utilities for manipulating its boundaries with App Inventor. First, a locking mechanism is provided to allow the map to be moved relative to other components on the Screen. Second, when unlocked, the user can pan the Map to any location. At this new location, the “Set Initial Boundary” button can be pressed to save the current Map coordinates to its properties. Lastly, if the Map is moved to a different location, for example to add Markers off-screen, then the “Reset Map to Initial Bounds” button can be used to re-center the Map at the starting location.

Properties

BoundingBox

Sets or gets the current boundary for the map’s drawn view. The value is a list of lists containing the northwest and southeast coordinates of the current view in the form ((North West) (South East)).

CenterFromString

Set the initial center coordinate of the map. The value is specified as a comma-separated pair of decimal latitude and longitude coordinates, for example, 42.359144, -71.093612.In blocks code, it is recommended for performance reasons to use PanTo with numerical latitude and longitude rather than convert to the string representation for use with this property.

EnablePan

Enables or disables the ability of the user to move the Map.

EnableRotation

Enables or disables the two-finger rotation gesture to rotate the Map.

EnableZoom

Enables or disables the two-finger pinch gesture to zoom the Map.

Features

Gets the list of features attached to the Map (without regard to the value of the feature’s Visible property). This list also includes any features created on the Map by calls to FeatureFromDescription.

Height

Specifies the Map’s vertical height, measured in pixels.

HeightPercent

Specifies the Map’s vertical height as a percentage of the Screen’s Height.

Latitude

Gets the latitude of the center of the Map. To change the latitude, use the PanTo method.

LocationSensor

Uses the provided LocationSensor for user location data rather than the built-in location provider.

Longitude

Gets the longitude of the center of the Map. To change the longitude, use the PanTo method.

MapType

Sets or gets the tile layer used to draw the Map background. Defaults to Roads. Valid values are:

1. Roads
2. Aerial
3. Terrain

Note: Road layers are provided by OpenStreetMap and aerial and terrain layers are provided by the U.S. Geological Survey.

Rotation

Specifies the rotation of the map in decimal degrees, if any.

ScaleUnits

Specifies the units used for the scale overlay. 1 (the default) will give metric units (km, m) whereas 2 will give imperial units (mi, ft).

ShowCompass

Specifies whether to a compass overlay on the Map. The compass will be rotated based on the device’s orientation if a digital compass is present in hardware.

ShowScale

Shows a scale reference on the map.

ShowUser

Shows or hides an icon indicating the user’s current location on the Map. The availability and accuracy of this feature will depend on whether the user has location services enabled and which location providers are available.

ShowZoom

Specifies whether to show zoom controls or not.

UserLatitude

Returns the user’s latitude if ShowUser is enabled.

UserLongitude

Returns the user’s longitude if ShowUser is enabled.

Visible

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

Width

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

WidthPercent

Specifies the horizontal width of the Map as a percentage of the Screen’s Width.

ZoomLevel

Specifies the zoom level of the map. Valid values of ZoomLevel are dependent on the tile provider and the latitude and longitude of the map. For example, zoom levels are more constrained over oceans than dense city centers to conserve space for storing tiles, so valid values may be 1-7 over ocean and 1-20 over cities. Tile providers may send warning or error tiles if the zoom level is too great for the server to support.