The Cyberguide tool itself consists of a PC and a pen. The PC contains a built-in tracking device which reflects your position (the arrow symbol) in relation to the location of "Interesting Things" in the room. Interesting Things (IT's) are denoted on the PC screen by a star symbol.

Begin using Cyberguide by taking a few steps toward an IT. Notice the PC updates your position as you walk. The Cyberguide, however, does more than simply navigate you about the room. You can ask for a description and further information on any IT you wish to know more about.

As you move about the room, notice that some IT's may appear on screen, while others vanish. For example, as you step left, objects to your left move onto the screen and objects to your right move off the screen. The Cyberguide allows you to modify the screen's display in three ways.

Once you have begun using the Cyberguide, you can obtain instructions or information at any time by clicking the "Help" icon at the top of the screen. Click "Exit" to return to the former display.

You may have previous knowledge that a certain "Interesting Thing" is on exhibit in the room. To find the location of this IT, click the "Categories" icon. A selection of categories will be displayed. Clicking a given category will give you a list of titles to choose from. You can display a differnet list of titles by clicking a new category.

Once you find the IT title you're searching for, click the title. The screen will return to a room map display and the location of your IT will be denoted by a flashing star symbol.

Guide To The Source Code

The Visual Basic version of the Cyberguide program consists of two forms, the map form and the exit form. The map form is the main form of the program and as such contains all the objects used for normal execution execution of the program. The exit form is only displayed when a user attempts to exit the program. It prevents an unauthorized exit from the program.

Map Form - CG_MAP

Global constants - These are constants available to all subroutines.

• ITCOUNT - Maximum number of ITs that can be defined.
• BROWSER - Info browser file name.
• MAP - The map file name.
• ITICON - IT icon file name for an unclicked icon.
• R_ITICON - IT icon file name for a clicked icon.
• ITFILE - IT initialization file name.

Global variables - These are variables available to all subroutines.

• gChangeX, gChangeY (integer) - These store the number of units the map has moved.
• gTopMap, gBottomMap, gRightMap, gLeftMap (integer) - Form coordinates for each edge of the map view.
• gCenterX, gCenterY (integer) - Form coordinates for the center of the map view.
• gScale (single float) - Scaling factor used when zooming.
• gZoomIn, gZoomOut (integer) - Maximum zoom levels.
• gCurZoom (integer) - Current zoom level, no zoom is 0.
• gNewX, gNewY (long float) - New position of user icon.
• gNumITs (integer) Number of ITs that are currently defined.
• gITName(ITCOUNT) (array of string) Names of ITs.
• gITPositionX(ITCOUNT), gITPositionY(ITCOUNT) (array of long float) - Map coordinates of ITs.
• gITDesc(ITCOUNT) (array of string) - Short descriptions of ITs that will be displayed when IT icons are clicked.
• gITURL(ITCOUNT) (array of string) - URL of IT information.
• gCurITClicked (integer) - Index for currently clicked IT.
• gLabelVis (integer) - Flag that indicates whether description box is visible.

The map screen in Cyberguide that shows the user's location and the location of the ITs currently available for viewing. There are several objects which make up the map view, allow the user to manipulate the map and get information about the ITs; the user position icon, IT icons, IT description box, scroll bars, zoom buttons, center button, demo info button, help button, and various overlays.

- The user position icon shows the user his current location within the mapped area.
- IT icons show the user the location of the ITs.
- The IT description box gives a short description of the IT selected.
- The scroll bars allow the user to move the map.
- The zoom buttons allow the user to increase and decrease the map size.
- The center button centers the map view around the user's current location.
- The demo info button will allow the user to view a list of current ITs.
- The help button gives access to a help system.
- The overlays provide background and display labels.

Map View Objects

imgUserIcon - Icon that indicates the user's position.

Local variables:
None

Methods:
None

imgITIcon - Icon that indicates the IT's position.

Local variables:
newX, newY (integer) New coordinates of the IT description box.

Methods:
Click(index) - Toggles the display of the IT description box when the icon is clicked.

lblIT - IT description box.

Local variables:
X (variant) - Dummy variable.

Methods:
DblClick - Launches the info browser showing the web page of the selected IT when the description box is double clicked.

hsbMap - Horizontal scroll bar.

Local variables:
currentLeft (integer) - Current position of the left edge of the map.

Methods:
Change - Moves the map horizontally when the scroll buttons are clicked.
Scroll - Moves the map horizontally when the scroll tab is moved.

vsbMap - Vertical scroll bar.

Local variables:
currentTop (integer) - Current position of the top edge of the map.

Methods:
Change - Moves the map vertically when the scroll buttons are clicked.
Scroll - Moves the map vertically when the scroll tab is moved.

cmdZoomIn - Zoom in button.

Local variables:
index (integer) - Index for IT data structures.

Methods:
Click - Scales the map and icons such that they become larger when the button is clicked.

cmdZoomOut - Zoom out button.

Local variables:
index (integer) - Index for IT data structures.

Methods:
Click - Scales the map and icons such that they become smaller when the button is clicked.

cmdCenter - Center button.

Local variables:
moveX, moveY (integer) - The amount that the map will move.

Methods:
Click - Centers around the user icon when the button is clicked.

cmdInfo - Demo info button.
(Note: This function has not yet been implemented.)

Local variables:
None

Methods:
None

cmdHelp - Help button.

Local variables:
None

Methods:
Click - Launches the help system when the button is clicked.

picCover1 - Gray area above map view.

Local variables:
None

Methods:
None

picCover2 - Gray area below map view.

Local variables:
None

Methods:
None

picZoom - Provides the 'Zoom' label.

Local variables:
None

Methods:
None

imgMap - Image of map.

Local variables:
NoneMethods:
None

imgMapView - Viewable area of map.

Local variables:
None

Methods:
None

Functions that initialize the system and interface with the positioning system. There are several functions that initialize various data structures to be used by the map system.

- The function that loads the map form.
- The function that reads the IT data file.
- The function that initializes the IT icons.
- The function that signals an update from positioning system.
- The function that updates user position.
- The function that updates the IT positions.

Data Access Objects

Form_Load - Loads the form and initializes global variables.

Local variables:
index (integer) - Index for IT data structures.

Form_QueryUnload - Prompts for password before exiting program.

Local variables:
None

ReadITs - Reads the IT data file and initializes IT data structures.

Local variables:
index (integer) - Index for IT data structures.
filenum (variant) - File handle for IT data file.
Xpos, Ypos (variant) - Map coordinates from data file.

CreateITs - Sets up the IT icons.

Local variables:
index (integer) - Index for IT data structures.
Xcoord, Ycoord (integer) - Form coordinates for IT icon position.

PositionStrobe - Signals update from positioning system.

Local variables:
None

UpdateUserPos - Updates the user's position.

Local variables:
index (integer) - Index for IT data structures.
IconBottom, IconTop, IconLeft, IconRight (integer) - Edges of user icon.

UpdateITPos - Updates the ITs position.

Local variables:
index (integer) - Index for IT data structures.
IconBottom, IconTop, IconLeft, IconRight (integer) - Edges of IT icon.

UpdateAllPos - Calls UpdateUserPos and UpdateITPos.

Local variables:
None

IR positioning

comm1:

This control object contains the code for receiving serial data. It gets setup by Form_Load and is controlled by "timer1" and "timer2".

Note: The following two objects are unnecessary unless a real GPS is used.

timer1:

Provides interrupts at regular intervals. Sampling of user's position is done once per each interrupt from "timer1", which enables "timer2." Every "timer1" interval, "comm1" reads all characters from the buffer. The serial data is analyzed by comparing various parts of the trailing part of the input string by comparing it to values in a lookup table. If the data is incorrectly formatted, an error has occurred, and the position is unchanged. If the data indicates that the serial hardware has not been initialized, "timer2" is turned off and the code for the serial hardware is transmitted to the serial hardware and executed. "timer2" is turned back on.

timer2:

Sample interval timer. "timer2"'s interval determines the length of time the serial port is sampled. If "timer2" elapses before valid data is read, a flag is set to stop reading serial data.

Exit Form (CG_EXIT)

Global constants

PASSWORD - Password for exiting the program.

Global variables None

Exit

There are several objects that make up the exit screen; the text box, box label, cancel button, and OK buttonn

- The text box is where the password is typed.
- The box label provides the 'Enter password' label.
- The cancel button exits the exit screen.
- The OK button attempts to exit the program.

Exit Objects

txtPasswd - Box where the password is typed.

Local variables:
None

Methods:
None

lblPasswd - Label for password box.

Local variables:
None

Methods:
None

cmdCancel - Cancel button.

Local variables:
None

Methods:
Click - Exits the exit screen and returns to the map screen when the button is clicked.

cmdOK - OK button.

Local variables:
None

Methods:
Click - Checks the password typed in and exits the program if password is correct when the button is clicked.

Other functions:

Form_Activate - Initializes the form.

Local variables:
None