STITCHING OF PATHS FOR IMPROVED TEXT-ON-PATH RENDERING OF MAP LABELS
A wireless communications device obtains sets of map data for rendering portions of a map on a display of the device. The map data includes label data for rendering labels on the map for identifying map features. Once the map data is obtained, the wireless device generates a list of all the labels to be rendered on the map, and for each duplicated label in the list, determines whether the map features associated with the duplicated labels connect on the map. If the labels connect, the device then generates a reconstructed map feature and renders a single instance of the label for the map feature. Accordingly, a map feature, such as a path, can be rendered with a single label even if the map data for the map feature, including its associated labels, was transmitted over-the-air as discrete sets of data.
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This application claims priority from U.S. Provisional Patent Application No. 60/788,434 entitled “Methods and Apparatus for Dynamically Labelling Map Objects in Visually Displayed Maps of Mobile Communication Devices” filed on Mar. 31, 2006 and from U.S. Provisional Patent Application No. 60/787,541 entitled “Method and System for Distribution of Map Content to Mobile Communication Devices” filed on Mar. 31, 2006.
TECHNICAL FIELDThe present disclosure relates generally to wireless communications devices and, in particular, to techniques for generating map content on wireless communications devices.
BACKGROUNDWireless communications devices such as the BlackBerry™ by Research in Motion Limited enable users to download map content from web-based data sources such as BlackBerry Maps™, Google Maps™ or Mapquest™. Downloaded map content is displayed on a small LCD display screen of the wireless communications device for viewing by the user. The user can pan up and down and side to side as well as zoom in or out. Due to the small display on the device and due to the limited over-the-air (OTA) bandwidth, there is a need to optimize the delivery and handling of the map data.
With the increasing availability of wireless communications devices having onboard Global Positioning System (GPS) receivers for providing location-based services (LBS), the efficient delivery and handling of map data is increasingly important.
Map data, including label data for labelling map features, is communicated from map servers to wireless communications devices in discrete portions which are assembled client-side to provide the map content requested by the user. However, when reconstructing a map from discrete portions of data, however, redundant labelling can occur if labels associated with each portion of data are rendered for the same feature. Furthermore, even if redundant labels are suppressed, the label associated with a reconstructed map feature cannot be placed aesthetically in the center of the reconstructed feature but rather is placed in the center of one of the constituent elements of the feature.
Accordingly, a technique for efficiently and aesthetically labelling maps reconstructed from discrete portions of downloaded data remains highly desirable.
BRIEF DESCRIPTION OF THE DRAWINGSFurther features and advantages of the present technology will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTIONThe present technology provides, in general, a method of rendering a map on a display of a wireless communications device where the map data, including label data, is downloaded over-the-air in small, discrete portions or sets of data, each with its own label data for labelling features of the map. The wireless device generates a list of all the labels to be rendered on the map, and for each duplicated label in the list, determines whether the map features associated with the duplicated labels connect or coincide on the map. If the map features associated with the duplicated labels do coincide, a map application running on the device then generates a reconstructed map feature and renders a single (preferably centrally-positioned) instance of the label for the map feature. Accordingly, a map feature, such as a path, can be rendered with a single label even if the map data for the map feature, including its associated labels, was transmitted over-the-air as discrete sets of data containing redundant labels.
Thus, an aspect of the present technology is a method of displaying a map on a wireless communications device. The method includes steps of obtaining sets of map data for rendering portions of the map on a display of the device, the map data including label data for rendering labels on the map for identifying one or more map features and generating a list of all the labels to be rendered on the map. For each duplicated label in the list, the method entails determining whether the map features associated with the duplicated labels connect on the map. Finally, a reconstructed map feature is generated and a single instance of the label is rendered for the map feature.
Another aspect of the present technology is a computer program product that includes code adapted to perform the steps of the foregoing method when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
Yet another aspect of the present technology is a wireless communications device for enabling a user of the device to display a map on the device. The wireless device includes 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, the map data including label data for rendering labels on the map for identifying one or more map features. The wireless communications device further includes a memory for storing code to instruct a processor to generate a list of all the labels to be rendered on the map, determine, for each duplicated label in the list, whether the map features associated with the duplicated labels connect on the map, generate a reconstructed map feature, and render on the display of the device a single instance of the label for the map feature.
The details and particulars of these aspects of the technology will now be described below, by way of example, with reference to the attached drawings.
The wireless communications device 102 preferably includes a visual display 112, e.g. an LCD screen, a keyboard 114 (or keypad), and optionally one or more auxiliary user interfaces (UI) 116, each of which is coupled to a controller 106. The controller 106 is also coupled to radio frequency (RF) transceiver circuitry 108 and an antenna 110. Typically, controller 106 is embodied as a central processing unit (CPU) which runs operating system software in a memory device (described later with reference to
The wireless communications device 102 sends communication signals to and receives communication signals from network 104 over a wireless link via antenna 110. RF transceiver circuitry 108 performs functions similar to those of station 118 and Base Station Controller (BSC) 120, including, for example, modulation and demodulation, encoding and decoding, and encryption and decryption. It will be apparent to those skilled in the art that the RF transceiver circuitry 108 will be adapted to the particular wireless network or networks in which the wireless communications device is intended to operate.
The wireless communications device 102 includes a battery interface 134 for receiving one or more rechargeable batteries 132. Battery 132 provides electrical power to electrical circuitry in the device 102, and battery interface 134 provides for a mechanical and electrical connection for battery 132. Battery interface 134 is couple to a regulator 136 which regulates power to the device. When the wireless device 102 is fully operationally, an RF transmitter of RF transceiver circuitry 108 is typically keyed or turned on only when it is sending to network, and is otherwise turned off to conserve resources. Similarly, an RF receiver of RF transceiver circuitry 108 is typically periodically turned off to conserve power until it is needed to receive signals or information (if at all) during designated time periods.
Wireless communications device 102 operates using a Subscriber Identity Module (SIM) 140 which is connected to or inserted in the wireless communications device 102 at a SIM interface 142. SIM 140 is one type of a conventional “smart card” used to identify an end user (or subscriber) of wireless device 102 and to personalize the device, among other things. Without SIM 140, the wireless communications device 102 is not fully operational for communication through wireless network 104. By inserting the SIM card 140 into the wireless communications device 102, an end user can have access to any and all of his subscribed services. SIM 140 generally includes a processor and memory for storing information. Since SIM 140 is coupled to SIM interface 142, it is coupled to controller 106 through communication lines 144. In order to identify the subscriber, SIM 140 contains some user parameters such as an International Mobile Subscriber Identity (IMSI). An advantage of using SIM 140 is that end users are not necessarily bound by any single physical wireless device. SIM 140 may store additional user information for the wireless device as well, including datebook (calendar) information and recent call information.
The wireless communications device 102 may consist of a single unit, such as a data communication device, a cellular telephone, a Global Positioning System (GPS) unit, a multiple-function communication device with data and voice communication capabilities, a wireless-enabled personal digital assistant (PDA), or a wireless-enabled laptop computer. Alternatively, the wireless communications device 102 may be a multiple-module unit comprising a plurality of separate components, including but in no way limited to a computer or other device connected to a wireless modem. In particular, for example, in the block diagram of
The wireless communications device 102 communicates in and through a wireless communication network 104. The wireless communication network may be a cellular telecommunications network. In the example presented in
Tower station 118 is a fixed transceiver station. Tower station 118 and BSC 120 may be referred to as transceiver equipment. The transceiver equipment provides wireless network coverage for a particular coverage area commonly referred to as a “cell”. The transceiver equipment transmits communication signals to and receives communication signals from wireless communications devices 102 within its cell via station 118. The transceiver equipment normally performs such functions as modulation and possibly encoding and/or encryption of signals to be transmitted to the wireless communications device in accordance with particular, usually predetermined, communication protocols and parameters. The transceiver equipment similar demodulates and possibly decodes and decrypts, if necessary, any communication signals received from the wireless communications device 102 transmitting within its cell. Communication protocols and parameters may vary between different networks. For example, one network may employ a different modulation scheme and operate at different frequencies than other networks.
The wireless link shown in communication system 100 of
For all wireless communications devices 102 registered with a network operator, permanent data (such as the user profile associated with each device) as well as temporary data (such as the current location of the device) are stored in the HLR 132. In case of a voice call to the wireless device 102, the HLR 132 is queried to determine the current location of the device 102. A Visitor Location Register (VLR) of MSC 122 is responsible for a group of location areas and stores the data of those wireless devices that are currently in its area of responsibility. This includes parts of the permanent data that have been transmitted from HLR 132 to the VLR for faster access. However, the VLR of MSC 122 may also assign and store local data, such as temporary identifications. Optionally, the VLR of MSC 122 can be enhanced for more efficient co-ordination of GPRS and non-GPRS services and functionality (e.g. paging for circuit-switched calls which can be performed more efficiently via SGSN 126, and combined GPRS and non-GPRS location updates).
Serving GPRS Support Node (SGSN) 126 is at the same hierarchical level as MSC 122 and keeps track of the individual locations of wireless devices 102. SGSN 126 also performs security functions and access control. Gateway GPRS Support Node (GGSN) 128 provides internetworking with external packet-switched networks and is connected with SGSNs (such as SCSN 126) via an IP-based GPRS backbone network. SGSN 126 performs authentication and cipher setting procedures based on the same algorithms, keys, and criteria as in existing GSM. In conventional operation, cell selection may be performed autonomously by wireless device 102 or by the transceiver equipment instructing the wireless device to select a particular cell. The wireless device 102 informs wireless network 104 when it reselects another cell or group of cells, known as a routing area.
In order to access GPRS services, the wireless device 102 first makes its presence known to wireless network 104 by performing what is known as a GPRS “attach”. This operation establishes a logical link between the wireless device 102 and SGSN 126 and makes the wireless device 102 available to receive, for example, pages via SGSN, notifications of incoming GPRS data, or SMS messages over GPRS. In order to send and receive GPRS data, the wireless device 102 assists in activating the packet data address that it wants to use. This operation makes the wireless device 102 known to GCSN 128; internetworking with external data networks can thereafter commence. User data may be transferred transparently between the wireless device 102 and the external data networks using, for example, encapsulation and tunnelling. Data packets are equipped with GPRS-specific protocol information and transferred between wireless device 102 and GGSN 128.
Those skilled in the art will appreciate that a wireless network may be connected to other systems, possibly including other networks, not explicitly shown in
The wireless communications device 202 will normally incorporate a communication subsystem 211, which includes a receiver 212, a transmitter 214, and associated components, such as one or more (preferably embedded or internal) antenna elements 216 and 218, local oscillators (LO's) 213, and a processing module such as a digital signal processor (DSP) 220. Communication subsystem 211 is analogous to RF transceiver circuitry 108 and antenna 110 shown in
The wireless device 202 may send and receive communication signals over the network after required network registration or activation procedures have been completed. Signals received by antenna 216 through the network are input to receiver 212, which may perform common receiver functions as signal amplification, frequency down conversion, filtering, channel selection, and the like, and, as shown in the example of
Network access is associated with a subscriber or user of the wireless device 202, and therefore the wireless device requires a Subscriber Identity Module or SIM card 262 to be inserted in a SIM interface 264 in order to operate in the network. SIM 262 includes those features described in relation to
Wireless communications device 202 includes a microprocessor 238 (which is one implementation of controller 106 of
Microprocessor 238, in addition to its operating system functions, enables execution of software applications on the wireless device 202. A predetermined set of applications which control basic device operations, including at least data and voice communication applications, will normally be installed on the device 202 during its manufacture. For example, the device may be pre-loaded with a personal information manager (PIM) having the ability to organize and manage data items relating to the user's profile, such as e-mail, calendar events, voice mails, appointments, and task items. Naturally, one or more memory stores are available on the device 202 and SIM 256 to facilitate storage of PIM data items and other information.
The PIM application preferably has the ability to send and receive data items via the wireless network. PIM data items may be seamlessly integrated, synchronized, and updated via the wireless network, with the wireless device user's corresponding data items stored and/or associated with a host computer system thereby creating a mirrored host computer on the wireless device 202 with respect to such items. This is especially advantageous where the host computer system is the wireless device user's office computer system. Additional applications may also be loaded into the memory store(s) of the wireless communications device 202 through the wireless network, the auxiliary I/O subsystem 228, the serial port 230, short-range communications subsystem 240, or any other suitable subsystem 242, and installed by a user in RAM 226 or preferably a non-volatile store (not shown) for execution by the microprocessor 238. Such flexibility in application installation increases the functionality of the wireless device 202 and may provide enhanced onboard functions, communication-related functions or both. For example, secure communication applications may enable electronic commerce functions and other such financial transactions to be performed using the wireless device 202.
In a data communication mode, a received signal such as a text message, an e-mail message, or a web page download will be processed by communication subsystem 211 and input to microprocessor 238. Microprocessor 238 will preferably further process the signal for output to display 222 or alternatively to auxiliary I/O device 228. A user of the wireless device 202 may also compose data items, such as email messages, for example, using keyboard 232 in conjunction with display 222 and possibly auxiliary I/O device 228. Keyboard 232 is preferably a complete alphanumeric keyboard and/or telephone-type keypad. These composed items may be transmitted over a communication network through communication subsystem 211.
For voice communications, the overall operation of the wireless communications device 202 is substantially similar, except that the received signals would be output to speaker 234 and signals for transmission would be generated by microphone 236. Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, may also be implemented on the wireless device 202. Although voice or audio signal output is preferably accomplished primarily through speaker 234, display 222 may also be used to provide an indication of the identity of the calling party, duration on a voice call, or other voice call related information, as some examples.
Serial port 230 in
Short-range communications subsystem 240 of
A Maplet data structure is provided that contains all of the graphic and labelled content associated with a geographic area (e.g. map features such as restaurants (point features), streets (line features) or lakes (polygon features)). Maplets are structured in Layers of Data Entries (“DEntries”) identified by a “Layer ID” to enable data from different sources to be deployed to the device and meshed for proper rendering. Each DEntry is representative of one or more artefact or label (or a combination of both) and includes coordinate information (also referred to as a “bounding box” or “bounding area”) to identify the area covered by the DEntry and a plurality of data points that together represent the artefact, feature or label. For example, a DEntry may be used to represent a street on a city map (or a plurality of streets), wherein the carious points within the DEntry are separated into different parts representing various portions of the artefact or map feature (e.g. portions of the street). A wireless device may issue a request for the map server to download only those DEntries that are included within a specified area or hounding box representing an area of interest that can be represented by, for example, a pair of bottom left, top right coordinates.
As depicted in
The Maplet Index request results in a Maplet Index (i.e. only a portion of the Maplet that provides a table of contents of the map data available within the Maplet rather than the entire Maplet) being downloaded from the map server to the device, thereby conserving OTA (Over-the-Air) bandwidth and device memory caching requirements. The Maplet Index conforms to the same data structure as a Maplet, but omits the data points. Consequently, the Maplet Index is small (e.g. 300-400 bytes) relative to the size of a fully populated Maplet or a conventional bit map, and includes DEntry bounding boxes and attributes (size, complexity, etc.) for all artefacts within the Maplet. As the field of view changes (e.g. for a location-aware device that displays a map while moving), the device (client) software assesses whether or not it needs to download additional data from the server. Thus, if the size attribute or complexity attribute of an artefact that has started to move into the field of view of the device (but is not yet being displayed) is not relevant to the viewer's current context, then the device can choose not to display that portion of the artifact. On the other hand, if the portion of the artefact is appropriate for display, then the device accesses its cache to determine whether the DEntries associated with that portion of the artefact have already been downloaded, in which case the cached content is displayed. Otherwise, the device issues a request for the map server to download all the of the DEntries associated with the artifact portion.
By organizing the Maplet data structure in Layers, it is possible to seamlessly combine and display information obtained from public and private databases. For example, it is possible for the device to display an office building at a certain address on a street (e.g. a 1st z-order attribute from public database), adjacent a river (e.g. a 2nd z-order attribute from public database), with a superimposed floor plane of the building to show individual offices (e.g. 11th z-order attribute from a private database, accessible through a firewall).
Referring back to
As mentioned above, three specific types of requests may be generated by a wireless communications device (i.e. the client)—AOI requests, DEntry requests and Maplet Index requests. The requests may be generated separately or in various combinations, as discussed in greater detail below. An AOI (area of interest) request calls for all DEntries in a given area (bounding box) for a predetermined or selected set of z-order Layers. The AOI request is usually generated when the device moves to a new area so as to fetch DEntries for display before the device client knows what is available in the Maplet. The Maplet Index has the exact same structure as a Maplet but does not contain complete DEntries (i.e. the data Points actually representing artifacts and labels are omitted). Thus, a Maplet Index defines what Layers and DEntries are available for a given Maplet. A data or DEntry request is a mechanism to bundle together all of the required Dentries for a given Maplet.
Typically, AOI and Maplet Index requests are paired together in the same message, although they need not be, while DEntry requests are generated most often. For example, when a wireless device moves into an area for which no information has been stored on the device client, the Maplet Index request returns a Maplet Index that indicates what data the client can specifically request from the server 321, while the AOI request returns any DEntries within the area of interest for the specified Layers (if they exist). In the example requests shown on
In this particular implementation, a collection of 20×20 A-level Maplets (representing a 1×1 degree square) is compiled into a Maplet Block File (.mbl). An .mbl file contains a header which specifies the offset and length of each Maplet in the .mbl file. The same 20×20 collection of Maplet index data is compiled into a Maplet Index file (.mbx). The .mbl and .mbx file structures are set forth in Tables B and C, respectively.
In Table B, the offset of Maplet #0 is 0x0000—0000 since, in this particular example, the data structure is based on the assumption that the base address for the actual Maplet data is 0x0000—0C80. Therefore the absolute address for Maplet #0 data is: Maplet #0 Address=Base Address (0x0000—0C80)+Maplet #0 Offset (0x0000—0000), and additional Maplet addresses are calculated as: Maplet #(n+1) Offset=Maplet #(n) Offset+Maplet #(n) Length. If a Maplet has no data or does not exist, the length parameter is set to zero (0x0000—0000).
In Table C, the offset of Maplet Index #0 is 0x0000—0000 since, according to an exemplary embodiment the data structure is based on the assumption that the base address for the actual Maplet index data is 0x0000—0C80. Therefore, the absolute address for Maplet Index #0 data is: Maplet Index #0 Address=Base Address (0x0000—0C80)+Maplet Index #0 Offset (0x0000—0000), and additional Maplet index addresses are calculated as: Maplet Index #(n+1) Offset=Maplet Index #(n) Offset+Maplet Index #(n) Length. If a Maplet Index has no data or does not exist, the length parameter is set to zero (0x0000—0000).
Table D provides a high “byte-level” description of a Maplet for this example.
By way of a further example, the wireless network 200 depicted in
As shown in
The map server extracts generic map content from a Geographical Information Systems (GIS) map database (e.g. Navtech®, TelAtlas®, etc.) at a specified level of resolution (zoom level). Custom graphics associated with the query, such as highlighted route, pushpin for current position or street address, etc. are post-processed and merged by the server with the generic map content. Relevant screen graphics are then labelled, and the merged map graphic is compressed and delivered to the device for display.
In operation, a user of the wireless communications device 202 uses an input device such as keyboard 232 and/or thumbwheel 233 to cause the microprocessor 238 to open the map application 500 stored in the memory 224. Using the keyboard 232 and thumbwheel 233, the user specifies a map location on the map application 500. In response to this request/command, the microprocessor 238 instructs the RF transceiver circuitry 211 to transmit the request over the air through the wireless network 104. The request is processed by the AG 350 and forwarded into the data network (Internet) using standard packet-forwarding protocols to one or more of the public and/or private map servers 400, 410. Accessing a private map server 410 behind a corporate firewall 420 was described above with reference to
The downloaded map data can be cached locally in RAM 226, and displayed on the display 222 or graphical user interface (GUI) of the device after the map application 500 reconstructs or “stitches together” portions of features or constituent path segments to generate a reconstructed map feature or path, as will elaborated below, so that a single instance of the label can be centrally rendered for the reconstructed feature or path (provided it does not collide with another label of higher priority). If a further request is made by the user (or if the user wants a change in the field of view by zooming or panning), the device will check whether the data required can be obtained from the local cache (RAM 226). If not, the device issues a new request to the one or more map servers 400, 410 in the same manner as described above.
As described earlier, map data can optionally be downloaded first as a Maplet Index enabling the user to then choose which DEntries listed in the Index to download in full. Furthermore, as described earlier, the map application can include user-configurable context filtering that enables the user to filter out unwanted map features or artifacts by not downloading specific DEntries corresponding to those unwanted map features or artifacts.
As a variant, the wireless communications device can optionally include a Global Positioning System (GPS) receiver (“GPS chip”) 550 for providing location-based services (LBS) to the user in addition to map content. Embedding a GPS chip 550 capable of receiving and processing signals from UPS satellites enable the GPS chip to generate latitude and longitude coordinates, thus making the device “location aware”. To obtain local-based services, the map application within the wireless communications device sends a request to the map server for information relating to a city, restaurant, street address, route, etc. If the device is “location aware”, the request would include the current location of the device.
In lieu of, or in addition to, GPS coordinates, the location of the device can be determined using triangulation of signals from in-range base towers, such as used for Wireless E911. Wireless Enhanced 911 services enable a cell phone or other wireless device to be located geographically using radiolocation techniques such as (i) angle of arrival (AOA) which entails locating the caller at the point where signals from two towers intersect; (ii) time difference of arrival (TDOA), which uses multilateration like GPS, except that the networks determine the time difference and therefore the distance from each tower; and (iii) location signature, which uses “fingerprinting” to store and recall patterns (such as multipath) which mobile phone signals exhibit at different locations in each cell.
Operation of the systems described above will now be described with reference to the method steps depicted in the flowchart of
As depicted in
As further depicted in the flowchart of
For the purposes of this specification, “label” includes not only all conventional forms of labels, such as city names, street names, etc, but also any symbols or icons, such as highway number icons, or symbols or icons used to denote airports, tourist information kiosks, campgrounds, ferry crossings, etc. on large scale (regional) maps or restaurants, hotels, bus stations, etc. on city maps.
For the purposes of this specification, “map feature” means a path, road, street, highway or other route and also includes features such as a body of water (river, lake, bay, strait, sea, ocean), an island, a park or other geographical feature that can be rendered from two or more separate sets of map data (i.e. vectors) for which individual labels are provided (and which are thus potentially duplicated upon rendering).
In the example depicted in
Even if any duplicated labels are suppressed, the resulting map, as depicted in
These problems can be overcome by stitching or reconstructing paths (or other map features) to create reconstructed paths (or reconstructed features), as depicted in
In one implementation, this reconstruction (stitching) can be accomplished in the manner described in
For the reconstructed path, only a single instance of the label (e.g. “Main Street”) is rendered, preferably in a central position vis-à-vis the path (i.e. the most aesthetic place for the label). Since the path has been stitched together to form a single reconstructed path, the label can be displaced anywhere along the reconstructed path. Therefore, as shown by the dashed-line arrows in
Likewise, for the reconstructed map feature (in this example, the lake), only a single instance of the label (e.g. “Windy Lake”) is rendered, preferably in, a central, prominent location vis-à-vis the feature, provided it does not collide or interfere with another pre-existing or higher-priority label. Furthermore, because of the reconstruction of the feature, the feature is no longer composed of constituent parts for the purposes of labelling. Accordingly, the label can be displaced over the entire range of the feature, not just over the constituent part with which the label was originally associated. This provides much more leeway in finding a suitable position for a label on the map, i.e. a label position that does not collide or interfere with any other label. In order words, this stitching technique enables labels to be rendered in preferred positions (e.g. centrally, prominently, aesthetically, etc.) while providing maximal leeway for displacing the label in the event that it collides with another (pre-existing or higher-priority) label.
In the example shown in
In the example presented in
In the example depicted in
Unlike First Avenue and Second, the path label “Main Street” appears three times, and thus its link parameters need to determined. Determining link parameters (or link status) can be accomplished by comparing endpoints of each link segment, as depicted in
As depicted in
Likewise, the label list also accounts for linkage relationships between non-path map features such as the lake shown in
As further depicted in
Optionally, when the reconstructed path is generated, the length of each constituent path segment and/or the total length of the reconstructed path are stored. These values can be used to determine an initial starting point for centering each label vis-à-vis the midpoint of the reconstructed path. Knowledge of these values also facilitates repositioning of the label when a potential label collision is detected or foreseen. These values can be stored as further fields of the label list 700. Labels can thus be rendered, or virtually rendered, with reference to the center of the reconstructed path, which is the preferred technique. Alternatively, labels can be rendered (or repositioned in the virtual rendering process) by virtually rendering a label along a center of a middle segment (or the segment closest to the middle of the onscreen bounding box) and then, if all of the label does not fit along that segment, checking whether the segment is spliced to a further segment (i.e. checking whether a reconstructed path exists for that label).
Similarly, when reconstructing non-path features (i.e. features that are not lines but rather polygons), other dimensions such as, for example, the average horizontal width of the polygon feature, can be stored for each of the constituent elements of the non-path map feature and for the reconstructed map feature, also for the purposes of facilitating centered labelling of the reconstructed feature.
The label list 700 depicted in
The foregoing method steps can be implemented as coded instructions in a computer program product. In other words, the computer program product is a computer-readable medium upon which software code is recorded to perform the foregoing steps when the computer program product is loaded into memory and executed on the microprocessor of the wireless communications device.
This new technology has been described in terms of specific implementations and configurations which are intended to be exemplary only. The scope of the exclusive right sought by the Applicant is therefore intended to be limited solely by the appended claims.
Claims
1. A method of displaying a map on a wireless communications device, the method comprising steps of:
- obtaining sets of map data for rendering portions of the map on a display of the device, the map data including label data for rendering labels on the map for identifying one or more map features;
- generating a list of all the labels to be rendered on the map;
- for each duplicated label in the list, determining whether the map features associated with the duplicated labels connect on the map;
- generating a reconstructed map feature; and
- rendering a single instance of the label for the map feature.
2. The method as claimed in claim 1 wherein the step of rendering the single instance of the label comprises a step of rendering the label such that the label is aligned with a middle of the reconstructed map feature.
3. The method as claimed in claim 1 wherein the reconstructed map feature is a reconstructed path that is reconstructed from constituent path segments derived from separate sets of map data.
4. The method as claimed in claim 3 wherein the step of determining whether the map features associated with the duplicated labels connect on the map comprises a step of determining whether a first endpoint of a first path associated with the duplicated label matches a second endpoint of a second path also associated with the duplicated label.
5. The method as claimed in claim 4 wherein the step of rendering the single instance of the label comprises a step of rendering the label midway along the reconstructed path.
6. The method as claimed in claim 1 wherein the step of generating the reconstructed map feature comprises steps of:
- determining a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed map feature; and
- reversing the direction of one or more data vectors so that all data vectors in the reconstructed map feature have a common direction.
7. The method as claimed in claim 3 wherein the step of generating the reconstructed map feature comprises steps of:
- determining a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed path; and
- reversing the direction of one or more data vectors so that all data vectors corresponding to each constituent path segment in the reconstructed path have a common direction.
8. The method as claimed in claim 3 wherein the step of generating the reconstructed path comprises a step of storing a length of each constituent path segment and a total length of the reconstructed path.
9. The method as claimed in claim 7 wherein the step of generating the reconstructed path comprises a step of storing a length of each constituent path segment and a total length of the reconstructed path.
10. The method as claimed in claim 1 wherein the step of generating the list comprises a step of sorting the labels into alphabetical order.
11. A computer program product comprising code adapted to perform the steps of claim 1 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
12. The computer program product comprising code adapted to perform the steps of claim 2 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
13. The computer program product comprising code adapted to perform the steps of claim 3 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
14. The computer program product comprising code adapted to perform the steps of claim 4 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
15. The computer program product comprising code adapted to perform the steps of claim 5 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
16. The computer program product comprising code adapted to perform the steps of claim 6 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
17. The computer program product comprising code adapted to perform the steps of claim 7 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
18. The computer program product comprising code adapted to perform the steps of claim 8 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
19. The computer program product comprising code adapted to perform the steps of claim 9 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
20. The computer program product comprising code adapted to perform the steps of claim 10 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.
21. 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, the map data including label data for rendering labels on the map for identifying one or more map features; and
- a memory for storing code to instruct a processor to: generate a list of all the labels to be rendered on the map; determine, for each duplicated label in the list, whether the map features associated with the duplicated labels connect on the map; generate a reconstructed map feature; and render on the display of the device a single instance of the label for the map feature.
22. The wireless communications device as claimed in claim 21 wherein the processor renders the label such that the label is aligned with a middle of the reconstructed map feature.
23. The wireless communications device as claimed in claim 21 wherein the reconstructed map feature is a reconstructed path that is reconstructed from constituent path segments derived from separate sets of map data.
24. The wireless communications device as claimed in claim 23 wherein the processor determines whether a first endpoint of a first path associated with the duplicated label matches a second endpoint of a second path also associated with the duplicated label.
25. The wireless communications device as claimed in claim 24 wherein processor renders the single instance of the label midway along the reconstructed path.
26. The wireless communications device as claimed in claim 21 wherein the processor determines a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed map feature and then reverses the direction of one or more data vectors so that all data vectors in the reconstructed map feature have a common direction.
27. The wireless communications device as claimed in claim 23 wherein the processor determines a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed path and then reverses the direction of one or more data vectors so that all data vectors corresponding to each constituent path segment in the reconstructed path have a common direction.
28. The wireless communications device as claimed in claim 23 wherein the processor causes the memory to store a length of each constituent path segment and a total length of the reconstructed path.
29. The wireless communications device as claimed in claim 27 wherein the processor causes the memory to store a length of each constituent path segment and a total length of the reconstructed path.
Type: Application
Filed: Mar 26, 2007
Publication Date: Oct 18, 2007
Applicant: RESEARCH IN MOTION LIMITED (Waterloo)
Inventors: Gordon BOWMAN (Kemptville), Gerhard KLASSEN (Waterloo), Eric JOHNSON (Ottawa)
Application Number: 11/691,257
International Classification: G09G 5/00 (20060101);