Real-time spherical correction of map data
AssigneeResearch In Motion Limited
InventorsGordon Gregory Bowman, Gerhard Dietrich Klassen
Life of this patent
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Abstract
A method of displaying a map on a wireless communications device includes steps of obtaining map data for rendering the map to be displayed on the wireless communications device, generating corrected map data by applying a spherical correction factor to the obtained map data, and rendering the corrected map data to display the map on a display of the wireless communications device. The spherical correction factor corrects for map distortions that occur at northerly (or southerly) latitudes. Since the spherical correction factor is a simple correction to a 3×3 transformation matrix, this spherical correction can be easily applied without taxing the CPU limitations of small handheld devices.
Claims14
A method of displaying a map on a wireless communications device, the method comprising:
- obtaining map data for rendering the map to be displayed on the wireless communications device;
- when a selected zoom level of the map exceeds a predetermined zoom level, generating corrected map data by applying a first spherical correction factor to a first portion of the obtained map data by using a first fixed latitude to calculate the first spherical correction factor and by applying a second spherical correction factor to a second portion of the obtained map data by using a second fixed latitude to calculate the second spherical correction factor;
- and
- rendering the corrected map data to display the map on a display of the wireless communications device.
A computer-readable medium comprising code which when loaded into memory and executed by a processor of a wireless communications device is adapted to:
- obtain map data for rendering the map to be displayed on the wireless communications device;
- when a selected zoom level of the map exceeds a predetermined zoom level, generate corrected map data by applying a first spherical correction factor to a first portion of the obtained map data by using a first fixed latitude to calculate the first spherical correction factor and by applying a second spherical correction factor to a second portion of the obtained map data by using a second fixed latitude to calculate the second spherical correction factor;
- and
- render the corrected map data to display the map on a display of the wireless communications device.
A wireless communications device for enabling a user of the device to display a map
- on the device, the wireless device comprising:
- an input device for enabling the user to cause the device to obtain map data for rendering the map to be displayed on a display of the device;
- and
- a processor for generating corrected map data by applying a first spherical correction factor to a first portion of the obtained map data by using a first fixed latitude to calculate the first spherical correction factor and by applying a second spherical correction factor to a second portion of the obtained map data by using a second fixed latitude to calculate the second spherical correction factor when a selected zoom level of the map exceeds a predetermined zoom level;
- and
- a display for displaying the corrected map data for the map.
Dependencies are inferred from the claim text.