WO2001022192A2

WO2001022192A2 - A cartographic display accelerator method

Info

Publication number: WO2001022192A2
Application number: PCT/IL2000/000589
Authority: WO
Inventors: Elie Hantsis; Naftali Nissani
Original assignee: Powerloc Technologies Inc.
Priority date: 1999-09-23
Filing date: 2000-09-24
Publication date: 2001-03-29
Also published as: WO2001022192A3; AU7443300A; IL132046A; IL132046A0

Abstract

A cartographic display accelerator method is disclosed, specifically directed to allowing multiple virtual displays (D1) to operate in real time on a lesser number of display devices D2 (D1 >D2). Nonetheless, there are advantages of speed and facility when the method is applied to presenting even a single virtual display on a single display device (1); or a virtual display (D1) is a graphic window on a display device (1). The cartographic display accelerator includes the steps of: (A) accepting at least one formatted record including vector-representation cartographic data (1); (B) processing the at least one formatted record into at least one processor specific memory overlay (2); and (C) storing the at least one overlay for subsequent fetching to a real or virtual display device wherein operation of the device includes mapping from the at least one overlay to the display (3).

Description

A CARTOGRAPHIC DISPLAY ACCELERATOR METHOD

FIELD OF THE INVENTION

This invention generally relates to a method for improving the display of cartographic data in computerized systems. More specifically, the present invention relates to a method for improving the display of vector data in computerized systems, which are often cartography applications related.

BACKGROUND OF THE INVENTION

Cartographic data is presented in two basic ways, raster and vector.

Raster structures relate to a high-resolution array of photographic imagery such as satellite imagery, aerial photographic imagery, textured terrain simulation imagery, etc. Raster structures also relate to the format used in the final display of such imagery on interlaced-type CRTs.

Vector imagery relates to structures used for pen plotting, and to structures for display on vector graphic-type CRTs. Vector structures also relate to database records which often include alphanumeric classifications and labels in association with aggregations of linked coordinate strings. These database records are primarily intended for presentation on vector-type CRT displays or using pen plotters onto paper or a like substrate. However, vector structures are also amenable to presentation on raster display CRTs or on scanning-type printing devices (e.g. ink jet printers, Facsimile printers, etc.).

Typically, cartographic application related vector data is provided in formats like ESRI's ARC-INFO or ARC- VIEW, or in formats like MAP-LNFO. Other formats are also used, such as formats provides by census bureaus, geological survey institutes, etc. However, the problems related to large databases, where much data is stored in vector format, is substantially identical when the application is cartographic or when the application is non-cartographic; such as databases for finger print maps, voice print signature maps, printed circuit board overlay maps, integrated circuit etching maps, etc. Therefore, in the context of the present document, cartography is primarily relating to geographic type mapping representations, and when applicable also to non-geographic type mapping representations.

For substantially the same data content, vector data structures usually provide a representation in at least two orders of magnitude less storage space than would the equivalent raster structure. Because cartographic data usually relates to enormous quantities of data, vector structures are normally used.

Given the many recent advances in computerized mapping, urban and interurban maps are often immediately available from commercial data-providers. Since these data providers try to satisfy the needs of many different types of clients with the same database, records in the database inevitably include contents which is not of interest to the specific customer.

Additional burden is also transferred to the customer, when transforming this data into a data display representation. For example, one customer needs to see house number clearly while another customer is more concerned with seeing the load bearing characteristics of the streets.

One extremely problematic step remains for the customer, after addressing the character of the data to be displayed, especially if the data needs to be displayed in real time. There is a need in the art for any and all means that can help speed the process of displaying this data. More specifically, it would be preferable if this need could be accomplished without requiring a massive amount of parallel processors, drivers and display devices.

SUMMARY OF THE INVENTION

The present invention generally relates to a cartographic display accelerator method. This method is specifically directed to allowing multiple virtual displays Di_. to operate in real time on a lesser number of display devices D₂ (Dι>D₂). Nonetheless, there are advantages of speed and facility when the present invention is applies to presenting even a single virtual display on a single display device. In the context of the present invention, a virtual display is a graphic window on a display device.

Specifically, the present invention relates to a cartographic display accelerator method (hereinafter the "basic embodiment"), the method comprising the steps of: a) accepting at least one formatted record including vector-representation cartographic data; b) processing the at least one formatted record into at least one processor specific memory overlay; and c) storing the at least one overlay for subsequent fetching to a real or virtual display device wherein operation of the device includes mapping from the at least one overlay to the display.

In essence, the present invention provides for a rapid representation of cartographic data on a display device, because that data is preprocessed into the overlay format that is used in the memory buffer of that device. This preprocessing eliminates an enormous delay time that is required to accomplish the processing. Alternatively, storing the data in an overlay format substantially precludes updating the data from the display device, where the display device is part of a cartographic data workstation. Thus the user of the present invention will only view individual overlays or combinations thereof. However this display may be facile combined with other information derived from other data structures, and presented jointly on the display device. In the present context, a display device is a vector or raster CRT-type screen, a flat screen equivalent, a pen or jet plotter, etc.

Thus it should be recognized that a practical cartographic display unit would merge features of the present invention with featured of known methods. More specifically, the practical unit will use the present accelerator method for providing graphic cartographic components; such as road outlines, building outlines, waterways, bridges, elevation contours, infrastructure features (e.g. water towers, electric poles, etc), or monuments; all of which are graphically represented identically regardless of from what orientation the map is viewed. In conjunction with the present accelerator method, known methods would be used to properly orient associated texts; such as street names, building numbers, etc. This merging function is best accomplished at the processor associated with the physical display driver, although the known methods may benefit from pre-fetching and pre-computation of a present orientation and a few angular variants thereof. According to one embodiment of the present invention, accepting includes transforming a plurality of records in a cartographic database from a general interface format into a prerequisite format by: a) filtering out data elements not required for a cartographic displaying of predetermined detail, b) grouping filtered database records into cartographic regional units, and c) shortening coordinate representations in each grouped filtered record by implicitly associating coordinates therein with a regional coordinate-offset.

In this context there are two different ways of grouping and shortening; which are both independently useful and mutually compatible.

The first way involves cutting a cartographic data file into sub-files, substantially with each sub-file containing data for a geographically separable subset of the original file. For example, if the original cartographic file covered data in a spatial extent window from (0,0) to (2,2) then there could be four arbitrary sub-files groupings: having spatial extents from (0,0) to (1,1), from (0,1) to (1,2), from (1,0) to (2,1), and from (1,1) to (2,2). Continuing in this example, if all coordinate representation in the original cartographic file were in double precision, then the coordinate representations in the new sub files can be in single precision offsets to a double precision base coordinate, e.g. the south west corner of the sub-file spatial extent's window.

The second way involves cutting each graphic feature into a number of sub features. For example, a line on the ultimate cartographic display represents a bank of a meandering stream. In the original representation, this bank was a list of double precision coordinates. In the grouped and shortened representation, a first coordinate is in double precision and each subsequent coordinate is a half precision offset from the immediately preceding offset; or in the case of the first offset, from the immediately preceding double precision first coordinate (e.g. see Appendix 1). In this "second way", the regional unit may be a regional unit of the original list of double precision coordinates, or may be within a regional unit according to the "first way". Since the first way is a good data base accelerator for pre-fetching proximate windows to a current window, and since the second way is a good display device accelerator (especially since it involves doing quick integer arithmetic instead of time consuming double precision of floating point arithmetic), the two way can be used independently or in conjunction; without loss of generality.

Furthermore, processing the at least one formatted record into at least one processor specific memory overlay may be accomplished by representing the processor specific overlay according to either the "first way" or the "second way", and therein according tot the format of the specific memory overlay. It is substantially equivalent to assign the functions of filtering, processing and storing as inclusive within the accepting-step or within the processing-step of the basic embodiment of the cartographic accelerator method of the present invention.

According to the preferred embodiment of the present invention, storing includes: a) activating at least one virtual display ; and b) for each activated virtual display: i) from the stored overlays, fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate offset; ii) transferring the fetched overlay to a virtual display presenting device; iii) from the stored overlays, fetching a plurality of coordinate-offset substantially closest overlays to the transferred overlay; iv) from the fetched plurality of coordinate-offset substantially closest overlays, transferring at least one overlay to the virtual display presenting device according to a present elected regional unit and therein according to a present elected regional coordinate offset; and v) returning to the fetching (step i) until the activated virtual display is cancelled. Furthermore, according to the preferred embodiment of the present invention,

_• activating at least one virtual display includes activating more than one virtual displays on a single real display device.

• fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate-offset includes coordinating with data from a Global Positioning System or with a user specified location.

• transferring at least one overlay to the virtual display presenting device according a present elected regional unit and therein according to a present elected regional coordinate includes coordinating with data from a Global Positioning System or with a user specified location.

• activating at least one virtual display includes activating two virtual displays at different cartographic scales. Furthermore, therein it is preferred that activating two virtual displays at different cartographic scales includes substantially limiting the two virtual displays to presenting similar quantities of graphic detail.

• transferring an overlay (step ii or iv) includes real time querying of a regional load statistics database. Furthermore, therein it is preferred that querying includes designating a destination coordinate or a destination region. Furthermore, therein it is preferred that querying includes receiving a response from the regional load statistics database. Furthermore, therein it is preferred that receiving a response includes transferring a representation of the response to one of the at lease one activated virtual displays.

The present invention also relates to a program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for cartographic display acceleration, the method steps including: a) accepting at least one formatted record including vector-representation cartographic data; b) processing the at least one formatted record into at least one processor specific memory overlay; and c) storing the at least one overlay for subsequent fetching to a real or virtual display device wherein operation of the device includes mapping from the at least one overlay to the display.

Furthermore, the present invention relates to a memory media having stored thereon display device specific overlays of processed prerequisite formatted cartographic database records.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 illustrates a schematic view of a basic cartographic display accelerator;

Fig. 2 illustrates a schematic view of a preferred cartographic display accelerator; and

Appendix 1 describes an example of grouping and shortening coordinate representations into units and coordinate offsets therein.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 illustrates a schematic view of a basic cartographic display accelerator, including the method steps of a) accepting (1) at least one formatted record including vector-representation cartographic data; b) processing (2) the at least one formatted record into at least one processor specific memory overlay; and c) storing (3) the at least one overlay for subsequent fetching to a real or virtual display device wherein operation of the device includes mapping from the at least one overlay to the display. Fig. 2 illustrates a schematic view of a preferred cartographic display accelerator. The preferred embodiment of the present invention relates to a cartographic display accelerator method, the method comprising the steps of: transforming (11) a plurality of records in a cartographic database from a general interface format into a prerequisite format by: i) filtering out data elements not required for a cartographic displaying of predetermined detail, ii) grouping filtered database records into cartographic regional units, iii) shortening coordinate representations in each grouped filtered record by implicitly associating coordinates therein with a regional coordinate-offset;

(b) processing (2) the prerequisite formatted records into display device specific memory overlays;

(c) storing (3) the overlays;

(d) activating (31) at least one virtual display ; and

(e) (32) for each activated virtual display: i) from the stored overlays, fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate offset; ii) transferring the fetched overlay to a virtual display presenting device; iii) from the stored overlays, fetching a plurality of coordinate-offset substantially closest overlays to the transferred overlay; iv) from the fetched plurality of coordinate-offset substantially closest overlays, transferring at least one overlay to the virtual display presenting device according to a present elected regional unit and therein according to a present elected regional coordinate offset; and v) until the activated virtual display is cancelled, returning to step e(iii). More specifically, the preferred embodiment of the present invention relates artographic display accelerator method, the method comprising the steps of:

(a) using a computer processor, transforming a plurality of records in a commercial or like cartographic database from a general interface format, which is a format used to provide substantially non-customized data extracts from the database, into a prerequisite format by: i) filtering out data elements not required for a cartographic displaying of predetermined detail, for example, building outlines of less than a predetermined area when only large building are to be ultimately displayed, or curb-lines for streets of less than a predetermined width when only heavy truck routing applications are needed, etc. ii) grouping filtered database records into cartographic regional units, for example using quad-trees, or by county, township, and sector, or by predetermined latitude and longitude increments, etc. iii) shortening coordinate representations in each grouped filtered record by implicitly associating coordinates therein with a regional coordinate-offset; for example using double precision to represent a South West most corner point of a latitude - longitude square section, and then therein using single precision to represent the north and east distances from the corner point.

(b) processing the prerequisite formatted records into display device specific memory overlays; so that the data is available for immediate transfer and display without any substantial formatting transformations being required;

(c) storing the overlays; preferably using an indexing method that allows most rapid access and transferring;

(d) activating at least one virtual display ; and

(e) for each activated virtual display: e.g. windows or the like i) from the stored overlays, fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate offset; for example getting a single overlay which most closely overlaps with a desired location, even if that location is in the peripheral area of the overlay; ii) transferring the fetched overlay to a virtual display presenting device; wherein it is the responsibility of the display driver to present the preprocessed overlay in what ever region of the physical display that has been elected; iii) from the stored overlays, fetching a plurality of coordinate-offset substantially closest overlays to the transferred overlay; so that a change in the focal interest of a user to a neighboring adjacent region may be effected without transmission delay to the storage media of the overlays; iv) from the fetched plurality of coordinate-offset substantially closest overlays, transferring at least one overlay to the virtual display presenting device according to a present elected regional unit and therein according to a present elected regional coordinate offset; according an actually elected preference by the user; and v) until the activated virtual display is cancelled, returning to step e(iii); so that the user can continue to elect new interests with respect to the current display contents presentation.

According to one variation of the preferred embodiment of the present invention, activating at least one virtual display (step d) includes activating more than one virtual displays on a single display device. Since the overlays are already in the format of the display device, the display device driver need only effect easy real time operations, such as cut, paste, position, and perhaps magnify.

According to another variation of the preferred embodiment of the present invention, fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate-offset (step e(i)) is coordinated with data from a Global Positioning System or with a user specified location. The user, for example a taxi cab driver, may allow the selection to be driven by an automatic system, such as GPS, current cell phone ID, etc. Alternatively, the user, for example an ambulance dispatch operator, may query a database to provide a coordinate approximation for the fetching.

According to yet another variation of the preferred embodiment of the present invention, a present elected regional unit and therein according to a present elected regional coordinate (step e(iv)) is coordinated with data from a Global Positioning System or with a user specified location. This variation is an optional combination of the two prior options since a user may be interested in preparing a display overlay collection for a region between two coordinates, either of which may be elected or automatically selected.

According to still another variation of the preferred embodiment of the present invention, activating at least one virtual display (step d) includes activating two virtual displays at different cartographic scales. For example a regional map of major streets and a local presentation of the immediately surrounding side streets to a location in the region. Furthermore, according to the preferred embodiment of the present invention, the two virtual displays are substantially limited to presenting similar quantities of graphic detail. The operation of the system is improved when the stored overlays are of substantially the same size in bytes. This directly corresponds to an equalization of presentation detail in a vector formatted data environment.

According to a variation of the preferred embodiment of the present invention, transferring an overlay (step e(ii or iv)) includes real time querying of a regional load statistics database. For example for the current weather conditions, the traffic conditions, etc.

According to another variation of the preferred embodiment of the present invention, querying includes designating a destination coordinate or a destination region. Furthermore, according to the preferred embodiment of the present invention, querying includes receiving a response from the regional load statistics database. For example for current weather or traffic condition in the intervening section or for recommended routing thereto, etc. Furthermore, according to the preferred embodiment of the present invention, receiving a response includes transferring a representation of the response to one of the at lease one activated virtual displays. This representation may be alphanumeric or graphic. For example it may be a sun, a cloud, a lightning bolt, or the like. Alternatively, it may be a tow truck icon, a police shield icon, a road work icon, or the like.

The present invention also relates to a memory media having stored thereon display device specific overlays of processed prerequisite formatted cartographic database records, substantially using step (c) of the method of the present invention.

Numbers, alphabetic characters, and roman symbols are designated in the following sections for convenience of explanations only, and should by no means be regarded as imposing particular order on any method steps. Likewise, the present invention has been described with a certain degree of particularity, however those versed in the art will readily appreciate that various modifications and alterations may be carried out without departing from either the spirit or scope, as hereinafter claimed.

Appendix 1

Preliminary:

1) All Coordinates of points measured in previously defined dot length;

2) Every standard shape transformed so that difference between two adjacent points is no more then 254 (in dot length);

3) Coordinates of shape points rounded to nearest integer.

Point (in order of table) - Index + Shape File - Record Length = 6 (File Extension SHI)

X Global - Unsigned Short (2)

Y Global - Unsigned Short (2) X Local - Unsigned Char (1)

Y Local - Unsigned Char (1)

Coordinates of point are (X, Y) - (X Global * 256 + X Local, Y Global * 256 + Y Local)

Polyline or Polygon (in order of table) - Index File - Record length 12 (File Extension - SH3 or SH5)

Shape Address - Unsigned Short (2) Shape Page - Unsigned Char (1)

Address of Shape in Shape File = Shape Page 65536 + Shape Address Shape Count - Unsigned Char (1)

Number of Parts in Shape X Min Global - Unsigned Short (2) X Max Global - Unsigned Short (2)

Y Min Global - Unsigned Short (2)

Y Max Global - Unsigned Short (2)

All Points in Shape are between: X from X Min Global * 256 to (X Max Global + 1) * 256, Y from Y Min Global * 256 to (Y Max Global + 1) * 256

Polyline or Polygon (in order of table) - Shape File - Record Length = 8 for Shape Part Header and 2 for Shape Part Point (File Extension - FH3 or FH5)

From Shape Page * 65536 + Shape Address in Shape File Shape Part Header, (Shape Part Points from second Shape Part Point to last Shape Part Point), ..., Shape Part Header, (Shape Part Points from second Shape Part Point to last Shape Part Point).

Shape Part Header is

Point Count - Unsigned Short (2)

1. Total Number of Points in Shape Part minus 1

X Global - Unsigned Short (2)

Y Global - Unsigned Short (2)

X Local - Unsigned Char (1)

Y Local - Unsigned Char (1)

Coordinates of first point are (X, Y) = (X Global * 256 + X Local, Y

Global * 256 + Y Local)

Shape Part Point is

X Local - Signed Char (1) Y Local - Signed Char (1)

Coordinates of next point are (X, Y) = (X previous + X Local, Y previous + Y

Local)

Claims

CLAIMS:

1. A cartographic display accelerator method, the method including the steps of:

(a) accepting at least one formatted record including vector-representation cartographic data;

(b) processing the at least one formatted record into at least one processor specific memory overlay; and

(b) storing the at least one overlay for subsequent fetching to a real or virtual display device wherein operation of the device includes mapping from the at least one overlay to the display.

2. The method according to claim 1 wherein accepting includes transforming a plurality of records in a cartographic database from a general interface format into a prerequisite format by:

(a) filtering out data elements not required for a cartographic displaying of predetermined detail,

(b) grouping filtered database records into cartographic regional units, and

(c) shortening coordinate representations in each grouped filtered record by implicitly associating coordinates therein with a regional coordinate-offset.

3. The method according to claim 1 wherein storing includes:

(a) activating at least one virtual display ; and

(b) for each activated virtual display: i) from the stored overlays, fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate offset; ii) transferring the fetched overlay to a virtual display presenting device; iii) from the stored overlays, fetching a plurality of coordinate-offset substantially closest overlays to the transferred overlay; iv) from the fetched plurality of coordinate-offset substantially closest overlays, transferring at least one overlay to the virtual display presenting device according to a present elected regional unit and therein according to a present elected regional coordinate offset; and v) returning to the fetching (step i) until the activated virtual display is cancelled.

4. The method according to claim 3 wherein activating at least one virtual display includes activating more than one virtual displays on a single real display device.

5. The method according to claim 3 wherein fetching an overlay according to an elected regional unit and therein according to an elected regional coordinate-offset includes coordinating with data from a Global Positioning System or with a user specified location.

6. The method according to claim 3 wherein transferring at least one overlay to the virtual display presenting device according a present elected regional unit and therein according to a present elected regional coordinate includes coordinating with data from a Global Positioning System or with a user specified location.

7. The method according to claim 3 wherein activating at least one virtual display includes activating two virtual displays at different cartographic scales.

8. The method according to claim 7 wherein activating two virtual displays at different cartographic scales includes substantially limiting the two virtual displays to presenting similar quantities of graphic detail.

9. The method according to claim 3 wherein transferring an overlay (step ii or iv) includes real time querying of a regional load statistics database.

10. The method according to claim 9 wherein querying includes designating a destination coordinate or a destination region.

11. The method according to claim 9 wherein querying includes receiving a response from the regional load statistics database.

12. The method according to claim 11 wherein receiving a response includes transferring a representation of the response to one of the at lease one activated virtual displays.

13. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for cartographic display acceleration, said method steps including:

(a) accepting at least one formatted record including vector-representation cartographic data; (c) processing the at least one formatted record into at least one processor specific memory overlay; and

14. A memory media having stored thereon display device specific overlays of processed prerequisite formatted cartographic database records, substantially as hereinbefore described and illustrated.