com.dingi.dingisdk.maps

Class Projection

java.lang.Object

com.dingi.dingisdk.maps.Projection

public class Projection
extends java.lang.Object

A projection is used to translate between on screen location and geographic coordinates on the surface of the Earth. Screen location is in screen pixels (not display pixels) with respect to the top left corner of the map (and not necessarily of the whole screen).

Method Summary

Modifier and Type	Method and Description
double	calculateZoom(float minScale) Calculates a zoom level based on minimum scale and current scale from MapView
LatLng	fromScreenLocation(android.graphics.PointF point) Returns the geographic location that corresponds to a screen location.
LatLng	getLatLngForProjectedMeters(ProjectedMeters projectedMeters) Returns the LatLng for a spherical Mercator projected meters.
double	getMetersPerPixelAtLatitude(double latitude) Returns the distance spanned by one pixel at the specified latitude and current zoom level.
ProjectedMeters	getProjectedMetersForLatLng(LatLng latLng) Returns the spherical Mercator projected meters for a LatLng.
VisibleRegion	getVisibleRegion() Gets a projection of the viewing frustum for converting between screen coordinates and geo-latitude/longitude coordinates.
VisibleRegion	getVisibleRegion(boolean ignorePadding) Gets a projection of the viewing frustum for converting between screen coordinates and geo-latitude/longitude coordinates.
void	invalidateContentPadding()
android.graphics.PointF	toScreenLocation(LatLng location) Returns a screen location that corresponds to a geographical coordinate (LatLng).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

invalidateContentPadding

public void invalidateContentPadding()

getProjectedMetersForLatLng

@NonNull
public ProjectedMeters getProjectedMetersForLatLng(@NonNull
                                                            LatLng latLng)

Returns the spherical Mercator projected meters for a LatLng.

getLatLngForProjectedMeters

@NonNull
public LatLng getLatLngForProjectedMeters(@NonNull
                                                   ProjectedMeters projectedMeters)

Returns the LatLng for a spherical Mercator projected meters.

getMetersPerPixelAtLatitude

public double getMetersPerPixelAtLatitude(double latitude)

Returns the distance spanned by one pixel at the specified latitude and current zoom level.

The distance between pixels decreases as the latitude approaches the poles. This relationship parallels the relationship between longitudinal coordinates at different latitudes.

Parameters:

latitude - The latitude for which to return the value.

Returns:

The distance measured in meters.

fromScreenLocation

@NonNull
public LatLng fromScreenLocation(@NonNull
                                          android.graphics.PointF point)

Returns the geographic location that corresponds to a screen location. The screen location is specified in screen pixels (not display pixels) relative to the top left of the map (not the top left of the whole screen).

Parameters:

point - A Point on the screen in screen pixels.

Returns:

The LatLng corresponding to the point on the screen, or null if the ray through the given screen point does not intersect the ground plane.

getVisibleRegion

@NonNull
public VisibleRegion getVisibleRegion()

Gets a projection of the viewing frustum for converting between screen coordinates and geo-latitude/longitude coordinates.

This method ignores the content padding.

Returns:

The projection of the viewing frustum in its current state.

getVisibleRegion

@NonNull
public VisibleRegion getVisibleRegion(boolean ignorePadding)

Gets a projection of the viewing frustum for converting between screen coordinates and geo-latitude/longitude coordinates.

Parameters:

ignorePadding - True if the padding should be ignored, false if the returned region should be reduced by the padding.

Returns:

The projection of the viewing frustum in its current state.

toScreenLocation

@NonNull
public android.graphics.PointF toScreenLocation(@NonNull
                                                         LatLng location)

Returns a screen location that corresponds to a geographical coordinate (LatLng). The screen location is in screen pixels (not display pixels) relative to the top left of the map (not of the whole screen).

Parameters:

location - A LatLng on the map to convert to a screen location.

Returns:

A Point representing the screen location in screen pixels.

calculateZoom

public double calculateZoom(float minScale)

Calculates a zoom level based on minimum scale and current scale from MapView

Parameters:

minScale - The minimum scale to calculate the zoom level.

Returns:

zoom level that fits the MapView.