Abstract:
An apparatus and process for arranging and presenting situational awareness information on a computer display screen using maps and/or other situational awareness information so that greater amounts of relevant information can be presented to a user within the confines of the limited area on small computer screen displays. The map display layout for a screen display utilizes multiple, independent map displays arranged on a computer screen in order to maximize situational awareness information and display that information efficiency. By displaying single or multiple maps in a plurality of range bands arranged along the peripheral area of a display screen, wasted screen area is minimized. The ability to independently scale with respect to distance, time and velocity, as well as zoom and pan each map on the screen display further improves the display presentation. When connected to a communication network, the ability of the screen display to project real time images and the movement of objects further enhances the delivery of situational awareness information to the user.

Description:
This application claims benefit to U.S. application Ser. No. 60/089,607, filed Jun. 17, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a method for improving the display of situational awareness information by using single or multiple map or map based displays with peripheral range bands. Range bands are map or map based areas displayed on a display screen such that varying map scale within the range band allows for greater area to be displayed. 
     BACKGROUND 
     In recent years, prior art systems of displaying situational awareness information to users have moved from physical paper maps to digital maps displayed on computers. Recent advances in processing, display, and communications capabilities have resulted in the development of lightweight handheld computers for use in displaying digital information relating to a user&#39;s situational awareness. These systems, when coupled with modem distributed information systems, including wireless network technologies and accurate positional data from sources such as the Global Positioning System (GPS), have the potential to improve a user&#39;s situational awareness in both military and civilian applications. However, the utility of these lightweight computer systems in the situational awareness domain is limited by the ability of their small display screens to depict information on a small screen display with sufficient area and detail for the user to make informed decisions. 
     Many small screen displays currently in use in handheld computing systems are not square, and may present aspect ratios of 2.5:1 or greater. This can result in a waste of valuable screen area, especially when situational awareness information is projected where the user requires accurate information about the entire area surrounding a location of interest. With a typical north-up display orientation, a display screen will present more information on the east-west axis than on the north-south axis. This introduces an undesirable situation and orientation dependence on the presentation of awareness information. Another problem with presenting information on small screen displays is the conflict of resolution versus area coverage. If a small screen map display depicts an area large enough for use in situational awareness applications, it may lack necessary details. Conversely, if a large scale map displays sufficient detail, it may not present enough area to provide useful situational awareness information. 
     A need exists for a user to obtain situational awareness information such that a variety of information can be projected on a display device such that several different scale levels of information can be projected at once. In addition, by connecting the display device to a communication network, a need exists for a real-time display of a user&#39;s situational awareness information that changes with respect to movement by the user and/or point of interest. A need also exists for displaying a variety of different types of information. For example, in a military application, a solder might need to obtain situational awareness information that dynamically changes as the position of the solder changes such that the movements of the user are displayed on a hand held display device showing terrain map images while also dynamically obtaining and displaying threat information from a wireless communication network. This threat information could be information regarding the movements of enemy air or ground based assets against the solder&#39;s position and displayed as information over a terrain map based image. In civilian applications, a user might want a display screen to project real-time information relative to the movement of the user and other rescue or police pursuit units. 
     SUMMARY 
     An apparatus and process for arranging and presenting situational awareness information on a computer display screen using maps and/or other situational awareness information so that greater amounts of relevant information can be presented to a user within the confines of the limited area on small computer screen displays. The map display layout for a screen display utilizes multiple, independent map displays arranged on a computer screen in order to maximize situational awareness information and display that information efficiency. By displaying multiple maps sharing a single display screen, wasted screen area is minimized by using map aspect ratios closer to unity. The ability to independently scale, zoom, and pan each map on a screen display further improves the display presentation. One map display area on a screen display can be used to provide large-scale, high-detail information about a specific area, while a second map display area can provide smaller-scale coverage of an area. Alternatively, the two maps can be used to provide specific information about two different areas of interest. 
     Use of map display layouts with peripheral range bands are methods for efficiently presenting and enhancing the user&#39;s comprehension of map-based situational awareness information. While these methods have widespread applicability to all map-based displays, they are particularly well-suited for application to handheld or palmtop computer systems and their small display screens. Using multiple map display areas with peripheral range bands reduces the waste of valuable screen area and provides a detailed view of an immediate area of concern while maintaining a moderate level of information about a wider area of interest for the user. The peripheral range bands further extend the user&#39;s situational awareness by providing general cueing information about areas outside the area of interest depicted on the map display proper. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The summary of the invention, as well as the following detailed description of preferred embodiments, is better understood when read in conjunction with the accompanying drawings, which are included by way of example, and not by way of limitation with regard to the claimed invention. 
     FIG. 1 a  illustrates a prior art screen display projection of a map showing areas of interest. 
     FIG. 1 b  illustrates a prior art screen display projection of two maps showing different scale areas of interest. 
     FIG. 2 a  illustrates a central map and peripheral map areas. 
     FIG. 2 b  illustrates a screen display projecting points of interest in a single range band located on the edge of the screen display. 
     FIG. 3 a  illustrates a central map and peripheral map areas. 
     FIG. 3 b  illustrates a screen display projecting points of interest in multiple range bands located on the edge of the screen display. 
     FIG. 4 illustrates a screen display of a map projecting multiple range bands according to map distances with points of interest displayed on the screen display. 
     FIG. 5 illustrates a screen display of a map projecting multiple range bands spaced according to time intervals with points of interest displayed on the screen display. 
     FIG. 6 illustrates a screen display with dual images at different map scales. 
     FIG. 7 illustrates a communication system for dynamically updating points of interest on the screen displays. 
     FIG. 8 illustrates the calculation and projection of a point of interest on a screen display using a single range band. 
     FIG. 9 illustrates the calculation and projection of a point of interest on a screen display using multiple range bands. 
     FIG. 10 illustrates a flow chart of the algorithm. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 a  illustrates a prior art screen display projection of a map showing areas of interest. The displayed image  2  is projected on an oblong display screen such as the 640×240 pixel screens currently in use in some handheld computers. Points of interest such as a river  4 , forest  6  or building structure  8  can be displayed on the screen display  2 . FIG. 1 b  depicts an alternative arrangement of a dual map display layout, where two images of a map area are projected in separate screen areas on the screen display. The image  10  is a zoomed in projection of the image  2  and provides the user with greater resolution of the river  14 , forest  16  and building structure  18  that was displayed in FIG. 1 a.  A zoomed out image  12  shows the image  10  with a greater scale of the river  20 , forest  22  and building structure  24  providing less resolution but greater information of the overall situational awareness of the user. 
     However, one drawback of presenting multiple maps on the small screen display  2  is the loss of resolution as the display area is reduced to allow for additional map images to be projected. As additional map images are displayed, each additional map display area becomes increasingly small. To compensate for this effect, peripheral range bands can be used to enhance the user&#39;s peripheral awareness of the zone around the immediate area shown on the main map display. Peripheral range bands utilize a narrow strip of pixels around the border of a map display to provide general information about the situation outside the area depicted on the central map display. Thus, the range band effectively compresses the map display on the periphery, where less detailed information regarding the user&#39;s overall situational awareness is less important than the highly detailed information corresponding to an immediate area of concern to the user. 
     FIG. 2 a  illustrates an image having the same scale across the central map area  26  and peripheral map area  28 . Points of interest denoted as items  30  and  32  are located in the immediate and specific area of the user and their importance for situational awareness is higher than items  34  and  36 . 
     FIG. 2 b  illustrates a screen display projecting the same central map area  26  and peripheral map area  28  using two different scales to project the same image in a reduced overall area. Points of interest in the peripheral map area  28  are projected in a single range band  40  located on the edge of the screen display. The central map area  38  contains a representation of the central map area  26  of FIG. 2 a.  The range band  40  displays the less relevant information of the peripheral area  28  from FIG. 2 a.  Items of greater interest  30  and  32  from FIG. 2 a  are projected in the central map area  38  as items  42  and  44 , respectively. Items of lesser concern and interest  34  and  36  located in the peripheral map area  28  from FIG. 2 a  are projected in the peripheral range band area  40  as items  46  and  48 , respectively. 
     FIG. 3 a  illustrates a central map and peripheral map area with the same scale throughout the image. Using multiple peripheral range bands provides additional levels for transforming a larger area into a small screen display area. The original image in FIG. 3 a  shows a central map area  50  and a peripheral map area  52 . The peripheral area  52  will ultimately be divided into various bands with the same or varying thicknesses, preset or user defined. Typically, the dimensions of the various peripheral bands will represent increasing thicknesses of the peripheral area  52  as the total number of peripheral range bands is increased. The highest perspective level of information comes from the peripheral range bands surrounding the smaller scale map of the central map area  50 . This approach seamlessly provides more information about objects and events that occur closer to the area of interest and less information about occurrences on the periphery, while promoting efficient use of the user&#39;s limited screen display area. 
     In FIG. 3 a,  items  54  and  56  are located in the central map area and items  58  and  60  are located in the peripheral area  52 . The distance from the edge  61  of the central map area  50  to items  58  and  60  will determine their respective locations in the multiple peripheral range bands projected on the screen display. 
     For example, FIG. 3 b  illustrates a screen display projecting points of interest in multiple range bands located on the outer edge of the screen display. Items  70  and  72  are located in the central map area  62  of the screen display similar to the representation of the items in the central map area described in FIGS. 3 a.  However, unlike FIGS. 2 a  and  2   b  where only one peripheral range band was illustrated, FIG. 3 b  illustrates three range bands  64 ,  66  and  68 . The three range bands  64 ,  66  and  68  depict the information located in the peripheral area  52  of FIG. 3 a.    
     The placement of items or points of interest in the respective range bands is a function of the distance of the item or points of interest from the center of the central map area  50  and the location of the item or points of interest within the peripheral area  52 . The range bands  64 ,  66  and  68  can represent equal distance of the peripheral area  52 . For example, if the peripheral area  52  of FIG. 3 a  has a thickness 78 of 30 kilometers, then the three range bands  64 ,  66  and  68  can have equal thickness scales of 10 kilometers each. An alternative arrangement, provides for increasing thickness representations. The first range band  64  could have a thickness representation of 2 kilometers of the peripheral area  52 , the second range band  66  could have a thickness representation of the next 8 kilometers of the peripheral area  52 , and the third range band  68 , a thickness representation of the last 20 kilometers representing the total 30 kilometer thickness of the peripheral area  52 . 
     The previous example uses traditional map based distances. An alternative embodiment to distance representations could be time scales where the screen display tracks the movement of objects with respect to time. From the center of the central map area  62 , items  70  and  72  could represent positions of points of interest within a one hour time travel to the center of the central map area  62 . The corresponding peripheral range bands  64 ,  66  and  68  could represent time increments from the center of the central map area  62 , of two to twenty-four hours (one days of travel to the center of the central map area  62 ), twenty-four to seventy-two hours (one to three days of travel to the center of the central map area  62 ), and seventy-two to one hundred sixty-eight hours (three to seven days of travel to the center of the central map area  62 ). 
     A second alternative embodiment to distance and time representations could be velocity representations of items or points of interest relative to the movement of the center of the central map area  52 . If the center of the central map area is moving at a velocity of 20 kilometers per hour, the screen display could project items or points of interest that are moving at velocities that differ from the velocity of the center of the central map area  62 . For example, the screen display depicted in FIG. 3 b,  is mounted to a vehicle traveling at a velocity of twenty kilometers per hour. The central map area on the screen display projects all items traveling with a velocity between zero and twenty-five kilometers per hour. Items  70  and  72  are other vehicles traveling at the same twenty kilometers per hour and their respective position of the vehicle with the mounted screen display (denoted as the center of the central map area  62 ). Item  74  is located in the first range band  64  for objects traveling at a velocity of twenty-five to fifty kilometers per hour. Likewise, range bands  66  and  68  represent higher velocities. A user&#39;s ability to switch between distance, time and velocity scales assists in providing relevant information while minimizing information overload. 
     FIG. 4 illustrates a screen display of a map projecting multiple range bands according to map distances with points of interest displayed on the screen display. The central map area  80  projects a map image of interest to a user. Three peripheral range bands  82 ,  84  and  86  project items of interest outside the image projected in the central map area  80 . The first range band  82  represents items of interest within zero to ten kilometers. The second range band  84  represents items of interest within ten to thirty-five kilometers. The third range band  86  represents items of interest within thirty-five to eighty-five kilometers. In FIG. 4, the location of various military units  88  and  90  are displayed on the central map area  80 . Other military units of interest  92 ,  93 ,  94 ,  95  and  96  are displayed in the three range bands  82 ,  84  and  86 . The screen display obtains the location of items  88 ,  90 ,  92 ,  93 ,  94 ,  95  and  96  from periodic updates or from a communication network such as a wireless communication channel established between the screen display and a transmitter located at a base station, on a mobile platform, on an airborne platform, or from a satellite relay. Other dynamically obtained information such as the actual positions of various points of interest could be obtained via communication signals from the Global Positioning System (GPS) satellites. 
     FIG. 5 illustrates a screen display of a map projecting multiple range bands spaced according to time intervals with points of interest displayed on the screen display. The central map area  100  projects a map image of interest to a user. Two peripheral range bands  102  and  104  project items of interest outside the image projected in the central map area  100 . In this illustration, the items of interest  106 ,  107 ,  108 ,  109 ,  110 ,  120  and  122  are projected on the display screen  112  in range bands  102  and  104  that are measured with respect to a time interval. The first range band  102  projects items of interest that are within a one hour time zone. For example, the display screen  112  shows combat units  114 ,  116  and  118 . A combat unit commander might want to know all units that are capable of reaching his position within a one hour period of time. Those units located in the first range band  102  are  107 ,  108 ,  109 ,  120 , and  122 . The closest units to the combat unit commander&#39;s position are units  107 ,  108  and  109 . Those units located in the second range band  104  such as units  110  are located within a two to twenty-four hour time frame. During a time of crisis, the combat unit commander can immediately obtain information regarding other units ability to assist in a timely fashion. 
     FIG. 6 illustrates a screen display with dual images. The central map area  150  is displayed at the top of the screen display  152 . In the lower left hand area, a space  154  is provided for sensory touch input for receiving information from the user. The lower right hand area  156  displays a high level map including the surrounding areas outside the central map area  150 . The touch input area  154  can support input mechanisms for the user to select the number of range bands and the dimension of the range bands (distance, time, velocity of points or items of interest), as well as other desirable information. 
     FIG. 7 illustrates a communication network system for dynamically updating points of interest on a plurality of screen displays. In many instances the screen display will be mounted on a moveable platform where the user will have the capability to select the center of the central map area to the location of the user and the central map area will move as the user moves. For example, the screen display could be mounted on a hand-held computer that is carried by a user, on a vehicle or a ship. The user might want to select a digital map image projecting a central map area thousands of miles away from the screen display. At other times, the user will want the center of the central map area to move. The movement of the central map area will require a supply of real time or almost real time data regarding the position of the center of the central map area as will as mobile items of interest. 
     FIG. 7 illustrates a screen display  160  receiving real time information from a satellite  162  or an aerial platform such as an Airborne Warning and Control System (AWACS) or a Joint Surveillance Target attack Radar System (JSTARS)  164 . The AWACS system interface could provide real time aerial threats or resources for supporting air to ground attacks. The JSTARS system interface could provide information regarding the movement of friendly or enemy vehicles. In addition to receiving this information, the user also will need to supply information regarding its own position to these communications systems and to the headquarters  166  so that the user&#39;s position can be broadcast to other combat units. 
     An alternative embodiment includes locating the screen display on a ship  168  such as a vessel supporting the Surveillance Towed Array System (SURTASS). The information supplied to the screen display could include navigational chart information of the ocean bottom  170  so that the situational awareness of the ship  168  relative to shallow areas is displayed on the screen display. The location of enemy surface and subsurface threats  174  could be projected on the screen display located on the ship  168  or in small boats containing Special Forces personnel. 
     There are at least two general approaches for depicting situational awareness information using range bands. The first approach, uses a Cartesian coordinate projection to preserve the orthogonal relation between the central map area and the range bands. This algorithm has the disadvantage of not preserving the angle between the map center and the point of interest. For some calculations, this preservation of the angle can produce misleading calculations. The following algorithm supports a Cartesian projection of a point outside the central map area into peripheral range bands by: 
     1. Determining how far north (or south) the point of interest is from the edge of the central map area. 
     2. Comparing the distance from the point of interest to the central map edge with the width of the innermost range band. 
     3. If the distance is greater than the width of the inner most range band, go back to step 2 but use the next range band. 
     4. If the distance is within the width of the range band, subtract the cumulative width of all bands inside the current band from the distance between the point and the central map area, and divide the result by the width of the band to determine how far into the band the point lies. 
     5. Adding the pixel value of the edge of the central map area to the thickness of the bands inside the band containing the point and the fraction of the thickness of the band containing the point to determine the actual pixel value. 
     6. Repeating steps 1-5 to determine the east (or west) pixel value. 
     The second approach utilizes a bearing-preserving calculation to present situational awareness information within the range bands. This technique positions objects in range bands so that their angular relationship to the map center is preserved, ameliorating the problem of objects bunching up in the comers of the range bands that can occur when using the first approach. This second algorithm uses a bearing preserving projectin to display a point of interest outside the central map area into peripheral range bands by: 
     1. Determining the range and bearing from the center of the map to the point of interest. 
     2. Calculating the range from the center of the map to the map edge along that bearing. 
     3. If the range to the point of interest is less than the range to the map edge, the point of interest lies in the central map area. 
     4. If the range to the point is greater than or equal to the range to the map edge, determining the correct range band by successively adding range band widths to the range to the map edge until the sum is greater than the range to the point of interest. 
     5. Determining the depth of the point of interest within the appropriate range band by comparing the distance into the range band with the range band width. 
     6. Using the bearing value from step 1 and the known dimensions of the display area to determine which edge (top, bottom, left, or right) of the range band that the point of interest occupies. 
     7. Using the properties of similar triangles to determine the correct X and Y pixel offsets of the point of interest into the range band. 
     A summary of the variables and their respective descriptions is as follows: 
     L “Latitude/Longitude” point 
     L X  X-coordinate of L point 
     L Y  Y-coordinate of L point 
     P Pixel point 
     P X  X-coordinate of P point 
     P Y  Y-coordinate of P point 
     K Band # in which points is located 
     N Number of bands selected 
     C I  Range from map center to the inner edge of the innermost circular band 
     C i   w  Width of the “I”-th circular band (I=1, 2, . . . N) 
     S H   I  Range from map center to the horizontal edge of the innermost square band 
     S i   w  Width of the “T”-th square band (I=1, 2 . . . N) 
     α Angle between the line which connects given point with center of the map and X coordinate 
     L R  Range from map center to the point of interest L 
     L Δ  Radial range from the inner edge of the circular band to the L point 
     L 66    VAR  Radial range from the outer edge of the innermost square band to one L point. 
     P R  Range from map center to the P point 
     P Δ  Radial range from the inner edge of the square band to the P point 
     C w   VAR  Radial range from the inner edge of the innermost square band to the outer edge of the innermost circular edge 
     S w   VAR  Radial range from the inner edge of the innermost square band to the outer edge of the innermost circular edge 
     S I   VAR  Radial range from map center to the inner edge of the innermost square band 
     S I   W  Range from map center to the vertical inner edge of the innermost square band 
     i Index Variable 
     j Index Variable 
     FIG. 8 illustrates the coordinate range points for calculating a map range band. A map center  400  is chosen on a particular map of interest. For simplicity, FIG. 8 illustrates the calculation of locations of interest in the quadrant defined by the positive x ( 403 ) axis and the positive y ( 405 ) axis. The location of a point of interest L ( 402 ) represents a point that is to be plotted. The inner display screen defined by S I   W  ( 407 ) and S I   H  ( 409 ) will show points of interest out to the outer edge  408  of the outer square band  406 . The location of point L  402  lies off the display screen for the particular scale of the map shown on the display screen. Therefore, a range band  406  is provided on the screen display such that the specific scale of the map showing the map center  400  is maintained, while points of interest located in a circular band  410  are shown in the square band  406  bounded by the outer edge  404  of the square band  406  and the inner edge  408  of the square band  406 . The square band  406  is the area located in S W   i  ( 411 ) that will show the compressed area of the circular band  410 . 
     The inner edge  412  of the circular band  410  touches the inner edge  408  of the square band at location  417 . The thickness C w   i  ( 415 ) of the circular band  410  (distance between the inner edge  412  and the outer edge  416  of the circular band  410 ) can be preset or user defined. Regardless of the thickness C w   i  ( 415 ) of the circular band  410 , the thickness will be mapped to the area inside the narrower square band  406 . 
     The angle α ( 420 ) of the ray  413  is determined from the ray  413  that originates at the map center  400  and passes through the point of interest L ( 402 ) relative to the x coordinate  403  of the map center  400  and is calculated by:        α   =     arctan        (       L   y       L   x       )                              
     By knowing the map center  400  and the point of interest L ( 402 ), the distance L R  ( 401 ) between the two points can be calculated by:          L   R     =       L   y       sin                 α                              
     Also known is the distance between the map center  400  and the inner edge  412  of the circular band  406 . This distance is denoted by C I  ( 418 ). The distance between the point of interest L ( 402 ) and the inner edge  412  of the circular band  406 , L Δ  ( 422 ) can be obtained by taking the difference between the distance from the map center  400  to the point of interest L ( 402 ) and C I  ( 418 ). L Δ  ( 422 ) is the value for the distance inside the circular band  410  of L ( 402 ). L Δ  ( 422 ) can also be compared to the total thickness C w   i  ( 415 ) of the circular band  410  producing a ratio for calculating the distance along the ray  413  passing through the map center  400  and the point of interest L ( 402 ). The ratio is the value of L Δ   VAR  ( 421 ) and C W   VAR  ( 423 ). The distance along the ray  413  from the map center  400  to the inner edge  408  of the square band  406  is S I   VAR  ( 424 ). 
     Also calculated is the length of portion of the ray  413  that falls within in the square band  406  at the particular angle α ( 420 ). This length is denoted as S W   VAR  ( 426 ) and is multiplied by the ratio calculated from the distance along the ray  413  passing through the map center  400  and the point of interest L ( 402 ) to produce the value P Δ  ( 428 ). In this description, the map center  400  is the screen coordinate that is typically a pixel located in the center of the screen display area. Other embodiments might locate the screen coordinate in a location on the screen display at a pixel other than the center of the display screen area. It is this screen coordinate that is used for ploting the ray  413  from the screen coordinate to the point of interest P ( 432 ) on the display screen. For simplicity, the screen coordinate and the map center are given a common location  400 . The value P Δ  ( 428 ) added to the value of S I   VAR  ( 424 ) gives the distance P R  ( 430 ) of the point P ( 432 ) from the map center  400  along the ray  413  within the square band ( 406 ). If the distance P R  ( 430 ) is not located in the first circular range band, there is no need to compensate for a dead zone, thus P R  ( 430 ) is calculated by:          P   R     =       (         (       L   R     -     C   I     -       ∑     j   =   o       j   =     k   -   1              C   w   j         )            S   w   k       C   w   k         +     S   I   H     +       ∑     j   =   o       j   =     k   -   1              S   w   j         )     *     1     sin                 α                                
     If the distance P R  ( 430 ) is located in the first circular range band, there must be compensation for the dead zone, thus P R  ( 430 ) is calculated by:          P   R     =       (         (       L   R     -       S   I   H       sin                 α         )     *       S   w   1         C   w   1     +     C   I     -       S   I   H       sin                 α             +     S   I   H       )     *     1     sin                 α                                
     By knowing the value P Δ  ( 428 ), the point of interest P ( 432 ) ran displayed in the square band  406  along the P X  ( 434 ) and P Y  ( 436 ) values. The value of P X  ( 434 ) is calculated by: 
     
       
           P   X   =P   R * cos α 
       
     
     The value of P Y  ( 436 ) is calculated by: 
     
       
           P   y   =P   R  sin α 
       
     
     A dead zone  438  exists and is located in the area defined by the difference in the area defined by the inner edge  412  of the circular band  410  and the area defined by S I   W  ( 407 ) and S I   H  ( 409 ). The value of S I   W  ( 407 ) is calculated by:          S   I   W     =       C   I     *     cos        (     arc                   sin        (       S   I   H       C   I       )         )                                
     The dead zone area is located in the area defined by the points  440 ,  442  and  414  and the area defined by the points  444 ,  446 ,and  414 . In this dead zone  438 , instead of just using the distance C w   i  ( 415 ) of the circular band  410 , the distance C w   i  ( 415 ) must be added to the distance C W   VAR  ( 423 ) which is the distance from the visible map area on the display to the outer edge  416  of the circular band  410 . This distance will vary as α ( 420 ) changes. Angle α ( 420 ) can be determined by:        α   =     arctan        (       P   y       P   x       )                              
     The “dead zone”  438  computation is performed to compensate for the distance between the inner edge  408  of the square band at location  417  and the inner edge  412  of the circular band  410  where the point of interest L ( 402 ) is located. It is also possible to reverse the calculations and perform computations to move from point P ( 432 ) to point of interest L ( 402 ). These calculations are useful when the user desires additional information regarding distance and direction of the point of interest L ( 402 ) from the map center  400 . 
     FIG. 9 illustrates the coordinate range points for calculating multiple map range bands. The first step is to calculate which circular band that the point of interest L ( 500 ) lies in. For points of interest that are located in the inner most range band  504 , the calculations are the same as those described in FIG.  8 . For points of location L ( 500 ) that are located in the second bands  506  through subsequent range bands  508 , the distance L R  ( 510 ) of the point of interest L ( 500 ) from the map center  502  is calculated to determine which circular band the point of interest L ( 500 ) is located in. This is accomplished by comparing L R  ( 510 ) with the parameters of the inner and outer edges of the various range bands. If the point of interest L ( 500 ) is located outside the outer edge  512  of the last range band  508 , then the point of interest L ( 500 ) cannot be displayed. 
     FIG. 9 illustrates a graphical representation of the information that would be displayed to the user as well as the information source. The user display would project the inner square band  514  and a plurality of additional square bands  516 ,  518  and  520 . The information projected in the square bands  516 ,  518  and  520  would be generated from source information represented in the circular bands  504 ,  506  and  508 , respectively. 
     For example, for the point of interest L ( 500 ), the distance L R  ( 510 ) is calculated. This distance L R  ( 510 ) is compared with the inner and outer edges of the circular bands  504 ,  506  and  508 . By knowing the distance from the map center  502  to the inner edge of the first range band C I  ( 522 ) as well as the distances of the range bands C w   I  ( 524 ) through C w   n  ( 526 ), a calculation of the particular range band encompassing the point of interest L ( 500 ) can be made. In FIG. 9, the point of interest L ( 500 ) is located in the second range band  506  or C w   2 . 
     The information or points of interest located in the circular range bands  504 ,  506 , and  508  is compressed and displayed proportionally in the square bands  516 ,  518  and  520  according the proportions between the thickness of the circular range bands  504 ,  506  and  508  to the thickness of the square bands S w   1  ( 528 ), S w   i  ( 530 ) and S w   n  ( 532 ), respectively. In FIG. 9, three circular bands C w   1  ( 523 ), C w   i  ( 524 ) and C w   n  ( 526 ) are represented. Therefore, C w   i  ( 524 ) corresponds to C w   2  ( 524 ) and C w   n  ( 526 ) corresponds to C w   3  ( 526 ). Also, FIG. 9 illustrates the three circular range bands with equal thickness. This does not need to be the case and a typical display will project increasing thickness of the circular range band as the number of square bands C w   n  ( 526 ) increase. As an example, the inner square display might be at a scale of 1:10, while the first square band  504  might be projected at a scale of 1:100, the second square band projected at a scale of 1:1000 and the third square band projected at a scale of 1:10000. 
     To project the point of interest L ( 500 ) as point P in the square band  518 , the distance L R  ( 510 ) is determined at the angle α ( 534 ). The various scales of the inner display  514  bounded by the height S H   I  ( 536 ) and the width S W   I  ( 538 ) is either predefined or user determined on a dynamic basis, based on the requirements of the user. These requirements in many instances can change as the user&#39;s need for more or less precise information is required. 
     The ratio of the distance L Δ  ( 540 ) of the point of interest L ( 500 ) from the inner edge of the circular range band  506  to the distance C w   i  ( 524 ) of the circular range band  506  is used to calculate the distance P Δ  ( 542 ) along ray  544  in the square band  518  along angle α ( 534 ). 
     FIG. 10 illustrates a flow chart of the algorithms used to project the situational awareness displays. From the start box  600 , the angle α of the ray from the map center to the point of location L  602  is calculated. The distance from the map center to the point of interest is calculated  604  and the algorithm sets in box ( 606 ) I=1 (this will keep track of the circular range band), CL=0 (dummy variable to perform comparison) and CR=the range to the circular band to be tested. In box  608  CL is set equal to CR. In box  610 , CR is set equal to the value of CR plus the width of the circular band containing the point of interest. 
     The algorithm tests  612  whether the distance from the map center is less than or equal to the value of CR. If not, the value of I in box  614  is incremented by one and the algorithm tests  616  whether the value of I is greater than the number of range bands. If the test  616  is affirmative, the algorithm exits  618  and cannot display the point of interest L on the display. If the test  616  is negative, the algorithm adds another value of the distance representing the next circular range band CR  610 . 
     When the algorithm obtains a value of LR greater than or equal to CR from box  612 , the algorithm tests  620  whether the value of I is greater than 0 or the number of range bands is greater than or equal to one. If these two values are not achieved, then the algorithm exits  618  and cannot display the point of interest L on the display. If the values from box  620  are obtained, then the algorithm tests  622  whether I is equal to one. 
     The test in box  622  determines whether the point of interest L is located in the first circular range band. If the point of interest is located in the first circular range band, then the algorithm must account for the “dead zone.” If the point of interest L is not in the first circular range band, then R R  is set equal  624  to the distance from the map center to the inner edge of the circular range band I. 
     L Δ  is set equal  626  to the distance from the map center minus the distance from the map center to the inner edge of the circular range band I. The value of L Δ   626  represents the distance the point of interest L is located within the circular range band of interest along a ray from the map center at the angle α. The value of Spct is the percentage distance of the point of interest inside the circular band of interest and is calculated  628  by dividing L Δ  by the thickness of the circular range band I. 
     The distance  630  is calculated from the map center to the inner edge of the square range band I along the ray from the map center at the angle α. The distance  632  is then calculated from the map center to the outer edge of the square range band I along the ray from the map center at the angle α. The thickness  634  of the square range band along the ray from the map center to the point of interest along the angle α is calculated from the difference is the value calculated in box  632  and  630 , respectively. 
     The distance  636  from the map center to the location inside the square range band of the point of interest L is obtained from adding the distance  630  from the map center to the inner edge of the square range band I along the ray from the map center at the angle α with the value of the thickness  634  of the square range band multiplied by the percentage value obtained in box  628 . The point of interest L is then plotted  638  on the user display a distance from the map center along the angle α and the algorithm ends  640 . 
     Returning to box  622 , if the point of interest L is located in the first circular range band or a circular range band and correction for the “dead zone” must be calculated. The distance  642  from the map center to the inner edge of the circular range band I. The algorithm then calculates  644  the distance from the map center to the inner edge of the innermost square range band along the ray from the map center to the point of interest L at the angle α. The “dead zone” is compensated by the difference  646  between the distance  642  from the map center to the inner edge of the circular range band I and the distance  644  from the map center to the inner edge of the innermost square range band along the ray from the map center to the point of interest L at the angle α. The value of L Δ  is calculated from the difference  648  in the distance  604  from the map center to the point of interest and the distance  644  from the map center to the inner edge of the innermost square range band along the ray from the map center to the point of interest L at the angle α. 
     The distance  650  is then calculated from the map center to the outer edge of the square range band I along the ray from the map center at the angle α. Next, the distance  652  is calculated from the map center to the inner edge of the square range band I along the ray from the map center at the angle α. The thickness  654  of the square range band along the ray from the map center to the point of interest alone the angle a is calculated from the difference is the value calculated in box  650  and  652 , respectively. The value of Spct in box  656  (the percentage value of the point of interest inside the circular band of interest) is calculated by dividing L Δ  by the thickness of the circular range band I plus the amount of the “dead zone” calculated in box  646 . 
     The distance  658  from the map center to the location inside the square range band of the point of interest L is obtained from adding the distance  654  from the map center to the inner edge of the square range band I, along the ray from the map center at the angle α, with the value of the thickness  654  of the square range band multiplied by the percentage value obtained in box  656 . The point of interest L is then plotted  638  on the user display a distance from the map center along the angle α and the algorithm ends  640 . 
     While exemplary systems and methods embodying the present invention are shown by way of example, it will be understood, of course, that the invention is not limited to these embodiments. Modifications may be made by those skilled in the art, particularly in light of this disclosure. For example, each of the elements of the disclosed embodiments may be utilized alone or in combination with elements of the other embodiments.