Expedition ES

Expedition ES
By Ron Doerfler
(Last Modified: March 20, 2000)

Overview

Note: If you are having trouble figuring out how to get past the title screen, please refer to the last section of this manual.

Go outside on a mapping expedition! Turn your Palm or Visor into a portable surveying instrument with the power of a computer. How high is that tree, mountain, building? How high did the model rocket fly? How far is it across the river, lake, canyon? What's the distance between those places on opposite sides of that hill? Does the altitude and azimuth of that star match the altitude given for Vega in a planetarium program? All of these can be done in the field.

Export the data records to memos in CSV format and input them into a PC spreadsheet such as Microsoft Excel. Use the data with compass and straightedge to create maps on your own of the areas. Participate or compete in fun and educational activities in cartography.

Expedition ES requires only a string to take altitude and azimuth measurements (remember the old protractor altitude finder in school?). The altitude is the vertical angle from your present position to the top of another object or waypoint. The azimuth is the horizontal angle between a waypoint and another reference waypoint, taken from your present position. A loop at one end of the string can hold the stylus (or keys, etc.) for weighting for altitude. The other end can either be held against the left edge with a finger, or for convenience it can be taped and the pivot point calibrated. A waypoint/object is aligned with an edge of the device or display. After the string lies at the vertical or horizontal angle, the string is held and then pressed against the display to compute the angle. Sighting edges can be selected for up/down altitudes and 360-degree azimuths, and multiple data records are averaged for the internal calculations.

Expedition ES provides the following features:

Up to 32 user-named mapping waypoints.
Altitude measurements between waypoints.
Azimuth measurements between waypoints.
Distance entries between waypoints.
Data record management. Data export in CSV format.
Height calculations of objects based on data records. Scaled graphical display of results. User-defined measurement height automatically added.
Distance calculations of inaccessible waypoints based on data records (Registered Version). Scaled graphical display of triangulation with layers.
Entries and graphical displays in English and metric units. User-defined Step lengths.
Altitude and Azimuth measurements taken either with a loose string or with a string taped at a calibrated pivot point.
Written in Quartus Forth--compact, fast!
Detailed user manual with engaging activities.
Reasonable cost for Registered Version ($5)

Operation

Expedition ES is designed to be used without a high degree of familiarity with the Palm or Visor. Hardkeys are disabled when the program is being run to avoid accidental presses, particularly during measurements. Help ("?") buttons are located next to each function on the main page. Menu functions for Presets, Record Deletion and Export, and Options such as Preferences only exist on the main home page. Various error screens offer information to aid in correcting a mistake.

To use this program, a string is required longer than the Palm or Visor device. The string will be pressed against the display to measure its angle, so it should be thicker than a thread. The string can be tied in a loop at one end and the stylus can be inserted in the loop as a small weight for altitude measurements. A key-chain or other handy weight can be used if wind is a problem.

IMPORTANT: The unweighted end of the string must be positioned at the upper left edge of the Palm or Visor device, about 1/4-1/2" below the top of the display window. The calculated angles depend on the string pivot being on the left edge below the top of the display area.

The string can be loose if desired. In this case, the free end is simply pressed against the upper left edge of the device with one thumb or finger. Then the string angle will be measured by pressing on two different spots on the string.

Alternatively, and more conveniently for a series of measurements, the string can be taped at the free end to the device as shown in the figure above. Then the menu function Presetsà Fix Pivot Point is executed, and as described below the string is pressed in two spots in two different directions to locate the pivot point. Then the Use Pivot box is checked next to the Altitude and Azimuth buttons on the main page. Then the string doesn’t have to be held and only one spot needs to be pressed to measure the angle. The pivot point location is saved between sessions until changed.

I have found that a very durable pivot point can be created by using a small flat piece of plastic such as the clear bubble-plastic that covers small store items on cardboard. The plastic is folded in half and a needle used to make a small hole in the fold. The string is passed through and knotted. Then the folded plastic is taped flat to the device.

Once the string is created, the software is fully functional. These functions are described in detail below:

Menu Functions:

The menu functions, accessed only on the main page, include:

Presets:

Fix Pivot Point -- This function calibrates a fixed string end location (pivot). The string is stretched across the screen and two spots are pressed to create one line to the pivot point. Then the string is stretched across the screen in a much different direction and two spots are again pressed, resulting in a second line that would intersect the first at the pivot point. Select ReDo to erase the lines and begin again, Save to save the pivot point location, or Quit to return to the main page.

Input Step Distance-- This function must be completed in order to use the "steps" units when entering distances (otherwise you get an error message). Tap each of the four "digits" to get a three-digit number plus a decimal point. Select centimeters or inches and click OK.

Input Height -- This function allows you to enter a height above the ground that you hold the device when taking altitude measurements. This must be added to heights calculated from the altitude data, and is done automatically when they are calculated from within the program. The entry window is very similar to that for the Input Step Distance menu function above.

Record:

Export -- This function writes all the data records to memos, up to 64 per memo. The data, along with appropriate column headings, are written in comma-separated value (CSV) format. The memos are called " Expedition ES" followed by a date/timestamp and the Part# if a second or later memo. After the next hotsync to the PC, the memos can be opened, copied to Notepad or another editor, and saved as a filename with an extension .csv. Then the file can be opened in a spreadsheet such as Microsoft Excel. The columns may have to be adjusted a bit wider to be consistent, and then the data can be printed out for offline map creation.

Delete All -- This function deletes all the measurement data records. A confirmation window appears first.

Options:

Preferences -- This function allows preferences to be set and maintained between sessions. At present the only option is to bypass the title screen.

About… -- This function displays information about the software, including the version.

Main Functions:

The main functions, or activities, are accessed via the large buttons on the main page. Select the "?" button next to any activity for on-line help. The measurements are actually much easier to learn and take than what may be inferred from the detailed descriptions below. The activities include:

Sight Altitude -- This function provides the measurement of the altitude (vertical angle) of an object/waypoint from your present position. This altitude angle can be measured upward (0 to 90 degrees) or downward (0 to –90 degrees). As described at the beginning of this section, a string must be either taped or held against the left edge of the device at a level just below the top of the display screen. If the string is taped and the pivot point has been determined via the Presetsà Fix Pivot Point menu function, the Use Pivot box to the right of the large button should be checked.

When the activity button is selected, the first of four pages of eight waypoints each is presented. You can sequence through the pages using either the up/down arrows on the screen or the scroll-up/scroll-down hardkeys. The names of the waypoints (up to 15 characters) can be entered or edited on the dotted lines using Graffiti, the built-in keyboard, or any other general text entry means. Please give some name (even if it’s a letter or number) to any waypoint used as your measurements occur, as this is the only way you have of identifying measurement records.

Check in the Source column the box next to your present position/waypoint. The Source waypoint is always your position at the time any measurement is made. Then check in the Dest. column the waypoint (which can be an object) whose altitude angle will be measured. The checked boxes can be on different waypoint pages. Then click on OK.

The measurement screen then appears. Now depending on whether the Destination object is above or below you, the weighted string may or may not fall across the display screen when you sight the object along an edge. For that reason, you first choose an edge and a direction to sight along. The possible sighting edges are the top and left edges of the device, and you can sight in either direction along these edges. Simply swipe the stylus in the direction that you will sight along, and an arrow labeled "Sight" will appear along the appropriate edge. The Edge button allows you to re-swipe the sighting edge and direction.

Now sight along the edge in the sighting direction toward the top of the Destination object. Allow the weighted string to fall across the display screen. Then press the string against the device where it crosses the right edge to hold it in place. Lower the device and press on the string to register a crosshair point on the screen along the string. If a pivot point is not being used, repeat at another point along the string. The altitude angle is computed and displayed on the screen. Select the ReDo button to repeat the measurement, Save to save the measurement to a data record, or Quit to return to the main window. The data will not be saved if you quit without saving first.

Sight Azimuth -- This function provides the measurement of the azimuth (horizontal angle between a waypoint and another reference waypoint) of an object/waypoint from your present position. This azimuth angle is measured from the reference waypoint to the destination waypoint clockwise as seen from above (this direction is different between astronomical and nautical definitions). This angle ranges from 0 degrees to 359 degrees. As described at the beginning of this section, a string must be either taped or held against the left edge of the device at a level just below the top of the display screen. If the string is taped and the pivot point has been determined via the Presetsà Fix Pivot Point menu function, the Use Pivot box to the right of the large button should be checked.

When the activity button is selected, the first of four pages of eight waypoints each presented. You should enter names for any unnamed waypoints that you will be using, as described in the last section. There are three columns of checkboxes. Check in the Source column the box next to your present position/waypoint. The Source waypoint is always your position at the time any measurement is made. Then check in the Dest. column the waypoint (which can be an object) whose azimuth angle will be measured. Finally, check in the Ref. Column the reference waypoint from which the azimuth angle will be measured. The checked boxes can be on different waypoint pages. Also, there is nothing preventing you from entering North as the reference waypoint and taking azimuths from that direction. Click on OK when finished.

The measurement screen then appears. The device should be set down to lay horizontal (a rubber ball placed on the screen will show if it is tilted, but it’s not that critical). If you don’t want to lie down to take the measurement, a stool, flat rock, or other portable platform can be used. You will first align one edge of the device toward the reference waypoint, and then sight along the string, TOWARD the end against the left edge, in the direction of the Destination waypoint. Now depending on where the Destination waypoint is relative to the Reference, the string may or may not lie across the display screen when you sight the Destination. For that reason, you first choose an edge and a direction to sight toward the Reference for aligning the device. (It is easier to sight the Destination roughly and then turn the device so the string lies across the display screen, and then select the Reference sighting edge.) The possible sighting edges are the top and left edges of the device, and you can sight in either direction along these edges. Simply swipe the stylus in the direction that you will sight along, and an arrow labeled "Reference" will appear along the appropriate edge. The Edge button allows you to re-swipe the sighting edge and direction. Then align the device so the Reference is sighted along this edge in this direction.

Now sight along the string toward the Destination from the free end of the string to the fixed end on the left edge. Then press the string against the device where it crosses the right edge to hold it in place. Press on the string to register a crosshair point on the screen along the string. If a pivot point is not being used, repeat at another point along the string. The azimuth angle is computed and displayed on the screen. Select the ReDo button to repeat the measurement, Save to save the measurement to a data record, or Quit to return to the main window. The data will not be saved if you quit without saving first.

Enter Distance -- This function is used to enter the distance between two waypoints. When this activity is selected, the first of four waypoint pages is presented. Again, the waypoint names can be entered or edited. Select the Source and Destination waypoints. Select OK to continue to the distance entry screen.

Select the measurement units (steps, ft, m, km, or mi). To enter the distance in steps, the step distance must have been initialized with the Presetsà Input Step Distance menu option. Select whether the distance is to the base or top of the Destination (relevant if the Destination is a hill or tall object). Then tap the digit boxes to enter the distance in the selected units. One of the digit boxes must be a decimal point (this lies beyond the 9). Click on OK to exit and save the measurement data.

View Records – This function allows you to review all the data measurements that have been taken but not deleted. Each record is numbered along the top as the contents are displayed. Use the left/right arrows on the screen or the scroll-up/scroll-down hardkeys to sequence through the records in either direction (they wrap around). Click on Delete to delete a displayed record. Click on OK to exit to the main screen.

Calculate – this function provides on-board calculations of particular mapping information. Highlight the Height box to the right of the activity button to calculate and display height information of an object. Highlight the Distance box to calculate and display distance information about an inaccessible waypoint.

Each type requires that the appropriate data measurement records exist. For a Height calculation, the four pages of waypoints are presented for selecting an initial waypoint (Pt. 1), a second waypoint (Pt. 2), and a third waypoint for which the height is desired (Object), all of which lie in a straight line. There must be at least one data record of the altitude angle from Pt. 1 to the top of the Object or vice-versa, unless Pt. 1 is the same as Object, in which case the angle is assumed to be 90 degrees. There must also be at least one data record of the distance between Pt. 1 and Pt. 2. Finally, there must be at least one data record of the altitude angle from Pt. 2 to the top of the Object or vice-versa, unless Pt. 2 is the same as Object, in which case the angle is assumed to be 90 degrees. Pt. 1 cannot be the same as Pt. 2. The ground must be level. Multiple like data records will be averaged.

After verifying that the proper records exist, the program will display a diagram showing all distances and heights in meters and feet. Any preset measurement height previously entered through the Presetsà Input Height menu function is automatically added to the height of the object. The diagram is drawn to scale.

In order to get the height calculation shown in the figures above, the user followed the following steps:

The altitude from the Big Rock to the top of the Lighthouse was measured at 26 degrees.

The user walked from the Big Rock toward the Lighthouse and stopped at the Grass Clump. The distance was entered as 37.0 steps, with the step distance preset to 31.4 inches (giving 29.64m).

The altitude from the Grass Clump to the top of the Lighthouse was measured at 61 degrees.

In the Calculate Height function, the Big Rock was selected as Pt. 1, the Grass Clump as Pt. 2, and the Lighthouse as the Object.

If possible, the user could have walked all the way from the Big Rock to the base of the Lighthouse and entered that distance in Step 2. Then Step 3 would be skipped, and in Step 4 the Lighthouse would be selected as both Pt. 2 and the Object. Also, Pt. 1 and Pt. 2 can always be swapped without effect. It’s also not a bad idea to take a few altitude measurements at a time, to get the greater accuracy afforded by the built-in averaging of like data records. Finally, the altitudes from either or both points could have been measured from the top of the Lighthouse down to them—the software will detect this and correctly reverse the negative altitude angle for the calculation.

For a Distance calculation, the four screens of waypoints will be presented for selecting an initial waypoint (Pt. 1), a second waypoint (Pt. 2), and a third waypoint to which the distance is desired (Object). There must be at least one data record of the azimuth taken at Pt. 1 toward Object with reference Pt. 2. There must also be at least one data record of the distance between Pt. 1 and Pt. 2. Finally, there must be at least one data record of the azimuth taken at Pt. 2 toward Object with reference Pt. 1. Pt. 1, Pt. 2 and Object must be unique. Multiple like data records will be averaged.

After verifying that the proper records exist, the program will display a map showing distances in meters and feet. The map is drawn to scale. Tap on the Layer button to cycle through individual displays of map information, including the closest distance of Object to the line connecting Pt. 1 and Pt. 2. The software tries to intelligently place labels to minimize overlap in any given layer; in the odd case that there is some overlap that makes a distance unreadable, try swapping the Pt. 1 and Pt. 2 waypoints. The Distance calculation is not available in the evaluation version.

In order to get the distance calculation to the other side of a lake as shown in the figures, the user followed the following steps:

The user was positioned at the Bare Spot in the grass on one side of a lake. The azimuth of the Tree on the other side of the lake was measured from a reference, a Pebble, that the user will walk to for the second position, giving 36 degrees.

The user walked from the Bare Spot to the Pebble. The distance was entered as 73.0 steps, with the step distance preset to 31.4 inches (giving 58.25m).

The user was then positioned at the Pebble. The azimuth of the Tree on the other side of the lake was measured from a reference, the Bare Spot that the user started at, giving 247 degrees.

In the Calculate Distance function, the Bare Spot was selected as Pt. 1, the Pebble as Pt. 2, and the Tree on the other side of the lake as the Object.

Tapping the Layer button shows the different types of labels separately to minimize overlap. One layer shows additional information, as shown in the last screen capture above--the shortest (perpendicular) distance from the Object to the line connecting Pt. 1 and Pt. 2 is given, as well as the distances to that point from Pt. 1 and Pt. 2. The angles shown at the vertices represent the internal angles of the triangle. For Pt. 1 this value is always equal to the measured azimuth of the Object relative to Pt. 2, and for Pt. 2 it is equal to 360 degrees minus the azimuth of the Object relative to Pt. 1, as can be deduced by looking at the map.

Pt. 1 and Pt. 2 can be swapped as desired, which simply flips the map vertically. In fact, since the user ends up standing at the Pebble, it may be more intuitive if the Pebble were chosen as Pt. 1. Again, taking a few azimuth measurements at each position takes advantage of the automatic averaging capability of the software. And of course, the Object can lie on either side of the line from Pt. 1 to Pt. 2, and can lie above, below or between them to the side.

Activities

This section describes a few individual or group activities using Expedition ES that are both fun and educational.

A. A General Reference:

A really neat book on cartography and the enjoyment of creating your own maps in the field is:

Greenhood, David. Mapping. University of Chicago (1964, 1973,1981). ISBN: 0-226-30697-6

It's very engaging and very informative for high school age or greater. There may be other editions. Highly recommended.

B. Map an Area:

Set off on a cartographic expedition. Select a fairly large area with some prominent natural and man-made features. Collect altitude and azimuth measurements (perhaps relative to North using a compass), identifying appropriate waypoints as you traverse the area. Traverse mapping is simply walking or driving, taking distance measurements as you go along, as well as altitude and azimuth measurements. Some traverse maps are circuits, in which you eventually return to the starting point.

Create a map based on these measurements along the traverse route, either from the record display forms on the device or from printouts from records after exporting them and loading them into a spreadsheet. If the traverse route was a complete circuit, you will no doubt find some difference between the final and initial waypoint locations on your map, which should theoretically be identical. Redraw the map spreading the error among all the traverse legs, as described in the reference book above. To do this, you apportion the error vector among all the vertices of your traverse map according to the distance to each vertex. If you have access to a topographical map (such as a U.S. quadrant map), compare it to your own map!

The distance entry from a source waypoint is identified with the bottom or top of the destination waypoint. Therefore, a more complex map would have waypoints halfway up hills, etc.

Mapping methods include:

Walking along a straight line, measuring distances along the line to points opposite features, as well as the perpendicular walking distance off the line to each feature.
Radiations, i.e., taking azimuth angles to different points from a single point on the trail.
Intersections, i.e., triangulating inaccessible points by measuring the azimuth angles from multiple points.

C. A Treasure Hunt:

This is a fun competitive game. One person acts as a pirate burying treasure. This person performs some preparatory work before the activity. From a starting waypoint, find North with a compass. Measure some distance at some compass direction and place a stake in the ground. Place other stakes at different distances and angles and number each stake. Then create a treasure map or list of directions from the starting point, around to different places perhaps around hills or buildings. These points are just open spots without distinguishing features.

The map/directions are given to the others, who have compasses and begin at the starting waypoint (perhaps a big rock that would have been there since pirate times). Palms or Visors are used to follow the azimuth angles relative to North for the given list of distances, and ultimately each group selects the numbered stake closest to their ultimate destination. The ones selecting the correct stake win the contest.

The software finds the azimuth from the string alignment--the user doesn't enter a value. Therefore, to find the right azimuth direction, the user aligns the device toward North and the string in approximately the correct direction. Then the screen is tapped and re-tapped to arrive at the correct azimuth angle (this is easier than it sounds). Then the user aligns the string along the line displayed on the screen and sights along it.

D. Find a Height:

Find the height of a flagpole, mountain, tower, building, etc. in a flat area. Name a waypoint at a location some distance from the object and measure the altitude to the top of the object. Enter the distance (in steps or other units) from this first waypoint to a second waypoint directly toward the object. If the second waypoint is not at the object itself, measure the altitude from the second waypoint to the top of the object (for accuracy, this shouldn't be too steep). Then highlight the Height box and select the Calculate function. Select the two waypoints and the object (and again, one of the waypoints can be the same as the object) and click on OK to graphically display the height diagram with labels and distances. Manually check these either by using a protractor and ruler or by using a calculator and trigonometric identities.

As an alternative, find the height of a skyscraper or mountain, using a vehicle to travel and measure the distance between the two waypoints, entering the distance in miles. Compare to published values. Also, the altitude can be measured down from the object to one or both waypoints rather than up.

E. Find the Distance to an Inaccessible Place (Registered Version)

Select a lake, river, canyon, etc. to find the distance across. Name a waypoint at a location along the edge and measure the azimuth toward an object on the other side of the divide with the reference being a second waypoint along the same edge of the divide. The object on the other side doesn't have to lie between the two waypoints. Walk to the second waypoint, measuring and entering the distance between the two waypoints. Measure the azimuth toward the object with the reference being the first waypoint. Then highlight the Distance box and select the Calculate function. Select the two waypoints and the object (all must be unique) and click on OK to graphically display the map with labels and distances. Manually check these either by using a protractor and ruler or by using a calculator and trigonometric identities. Verify against topographical maps.

It is interesting (if more limited) to also measure distances to inaccessible places, or between places that cannot be traversed, using traditional non-Palm/Visor outdoor methods based on similar triangles:

Following the first diagram, you begin at A opposite an inaccessible feature D. Then you walk some distance parallel toward E, placing a stake or other marker in the ground. Then you walk on for the same distance to B, and then walk perpendicular to AB until you reach a point C where the marker at E lines up with D. Then the last distance you walked, BC, is the distance from A to D.

If AD is too far or BC cannot be traversed, this method can be modified in a more general way. In this case you walk from A some distance to B without stopping at E. Then you walk some distance from B to C. Then you view D from C, noting where the sight line crosses AB, which we will call E but will not generally be halfway between A and B. Now because of similar triangles, the AE/EB = AD/BC.

Another variation is shown in the next diagram. In this case, AB/BC = AE/ED, allowing the distance across the lake AE to be determined.

The next diagram shows yet another method of measuring between inaccessible points based on similar triangles. For the triangles to be similar, the points must be chosen so that the ratio of corresponding known sides are equal, i.e., ED/CD = AD/DB. Then the ratio of the third sides is the same: AE/CB = ED/CD = AD/DB. These ratios can be conveniently chosen—for example, if AD = 2*DB and ED = 2*DC, then AE = 2*CB.

In all of these cases, as well as in using Expedition ES, you should for greater accuracy choose angles that are not too narrow.

Conclusion

With all the features described above, Expedition ES provides a fun and educational software package for collecting and calculating mapping measurements. It can make your next field trip or outdoor class a more exciting, engaging experience.

Version History

Version 1.0: 03/24/00 First Release.

Where to Get Expedition ES

Expedition ES can be obtained by visiting www.eddiesoft.com, or for on-line purchase visit www.palmgear.com. Questions or comments can be sent to the author (Ron Doerfler) at activekey@earthlink.net.

Disclaimer

The software (Expedition ES) is provided "as is" without warranty of any kind, either express or implied, including, without limitation, the implied warranties of merchantability, fitness for a particular purpose, or non-infringement. The entire risk arising out of use or performance of the software remains with the user. In no event shall the author or any other party be liable for any damages whatsoever (including, without limitation, damages for loss of business profits, business interruption, loss of business information, or any other pecuniary loss) arising out of the use of or inability to use the software even if the author has been advised of the possibility of such damages. The author expressly disclaims any liability for errors or omissions in the content of the software. The user accepts full responsibility for any damages, consequential or otherwise resulting from using the software. The software is not to be used in any situation in which precision navigation or orienteering is required, or in any situation in which the safety or wellbeing of the user is dependent on its proper operation. It is distributed solely as an educational tool.

Getting Past the Title Screen

The text at the bottom of the title screen says "X marks the spot for entry." This means that you tap on the X treasure mark on the map (on the island at the lower middle) to proceed into the application itself. If you prefer, you can bypass the title screen entirely for future users through the Optionsà Preferences menu function on the main page.