FieldMap v3.2

After an delay, the initial Preferences display appears.

The drop-down Map: list shows all available map sets. On changing the selected map, the list of layers below is refreshed to show the layers available for the chosen map. Layers may be selected/deselected as required. The All and None buttons provide quick ways to select or deselect all layers.

The New layer button is disabled in this version.

At the top of the display, the three buttons Map Grid and Track, give access to various pages of preference settings. These are described below

After choosing a map and selecting the required layers, press the OK button to complete the initial setup and run the mapping program.

On PocketPC machines using the Jeode runtime system, the EVMConsole display reappears while the rest of the program is loaded. A message will appear indicating that a local Context Service has been started.

Next, the Map View appears, and map loading commences. As each map is loaded, its name appears in the message area near the top of the screen. In the picture, the message Loading 400090-1-2 indicates that the named raster layer (part of a scanned topographic map) is being loaded. Note that the first raster layer may take some time to load, but subsequent layers are loaded much more rapidly.

When map loading is complete, the message Map ready appears in the message area. The example shows several tiles of a scanned topographic map, part of a soil map (a colour raster layer exported from a GIS), and two vector layers representing roads (red) and water (blue).

Map view

TO DO brief description

First, a quick tour of the menus:

The View menu provides options to

• Return to the Preferences view
• Switch to the GPS view
• Refresh the view.

The Notes menu provides options to

• Manually record a point, line or polygon note.
• Use PS positions to record a point, line or polygon note.
• Add a point (enabled only when recording a line or polygon).
• End recording (enabled only when recording a line or polygon).
• Cancel recording (enabled only when recording a point, line or polygon).

For further details, see Creating FieldNotes.

The Zoom menu provides options to

• Zoom in, either x2 or x16.
• Zoom out, either x2 or x16.

The Exit menu provides a single option to confirm termination. Tap anywhere else to cancel.

Active areas in the Map view

Several areas of the map view respond to pen taps or mouse clicks. Tapping or clicking on

• the message bar refreshes the map display
• the activity indicator (square area at right hand end of the message bar, shown here in red to indicate that the GPS component is not running) switches to the GPS view
• the scroll areas (narrow margins along all four edges of the map, indicated by faint grey lines) causes the map to scroll in the required direction.
• anywhere else on the map results in the coordinates of the point being shown in the message bar.

GPS view

When first opened, the GPS data view shows the message GPS Stopped with all remaining fields empty. Note that certain fields (the coordinates at the top, number of satellites (SVs:) and the time field at the bottom) appear with a red background. This indicates that the data in these fields is missing or unreliable.

The View menu provides options to

• Return to the Preferences view
• Switch to the Satellite view
• Switch to the iFieldMap Map view

The GPS menu provides a single option to start and stop input from a GPS receiver. See also, Using a GPS receiver. When the receiver connection is stopped the menu choice is Start as shown here. Once the connection is running the menu changes to Stop and selecting this item again will close the connection.

GPS Satellite view

When first started, the Satellite view is also empty. It consists of two areas. At the top is the sky map, used to show positions of GPS satellites. At the bottom is a row of vertical bars, used to show the signal strengths received from satellites. see also Satellite view when running.

The Satellite View menu provides options to

• Return to the Preferences view
• Switch to the GPS Location view
• Switch to the iFieldMap Map view

Preferences view

Once maps have been loaded, the Preferences view shows several more buttons at the top. Each of these gives access to an individual preferences page:

• Map
• Grid
• Track
• GPS
• Context
• Notes
• Heirport

Also visible on each preference page are the buttons:

• Cancel: abandon changes and revert to previous view.
• OK: accept changes and switch to previous view.

Map Preferences

• Map: a drop-list used to select the map collection to be used. When the selection is changed, the Layers list is reloaded to reflect the contents of the selected map collection.
• Layers: multiple selection pick-list of layers available in the current map collection. Determines which layers are shown in the map view
• All: select all layers in the current map collection.
• None: deselect all layers in the current map collection
• New: create a new map layer. A popup dialog allows entry of name, type (Note, Vector, Raster) and brief description.

  Note: the New Layer dialog is not enabled in this release. To add a new Layer, see Creating new map layers.

Grid Preferences

The first group of settings affect how the grid, coordinate lables, scale and scroll areas are shown on the MapView.

• Ticks draw tick marks around edge of map.
• Lines draw full grid lines across map.
• Labels show coordinate labels for grid ticks/lines.
• Scale show the scale bar.
• Scroll show and enable the scroll areas.
• Note Labels show note id labels adjacent to symbols.

• Survey Grid default length of grid unit in metres.
• Cells to left default number of cells (walkers) to left of FieldMap user.
• Cells to right default number of cells (walkers) to right of FieldMap user.
• Next Unit # default walker separation in metres.

Track Preferences

These settings affect display and recording of the users track and whether the map scrolls automatically with GPS location.

• Record record the track as a vector map layer.
• Follow GPS map is kept centred on GPS location.
• Line show the track as a line.
• Points show individual recorded points on the track.
• Min dist (m) the minimum distance in metres between recorded track points.
• Min time (s) the minimum time in seconds between recorded track points.

GPS Preferences

These settings control communication with the GPS receiver and the behavious of the GPS view.

• Protocol the communication protocol used by the GPS receiver. Usually, this is NMEA, but FieldMap can also be configured to work with Trimble TSIP, Garmin binary protocol and others. certain options below are only enabled when they are provided in the selected protocol.
• Coords the spatial reference system used for coordinate display in the GPS View. Normally this should be set to the same as that used in the map data.
• Velocity unit choose between kilometres per hour (km/m), metres pers second (m/s) or miles per hour (mph).
• Port the serial port device used to communicate with the GPS receiver. Available values are discovered automatically.
• Baud the baud rate (roughly, the speed in bits per second for the serial communication with the GPS receiver.
• UTC offset the offset in seconds between GPS and UTC time standards. Will be set automatically when this information is supplied by the receiver (only with some binary protocols).
• Set clock when selected, the computer system clock will be set using the UTC time derived from the GPS receiver.
• Alt MSL where available, show altitude relative to Mean Sea Level, rather than the geoid model.
• PR/CP rate where available, controls the rate at which raw pseudorange and/or carrier phase data is captured.
• Dbl prec where available, requests double precision fix data from the receiver.
• Static filter where available, use the static filter mechanism in the GPS receiver.
• Mask angle where available, set the mask angle in degrees. The mask angle is the elevation above the horizon below which satellites are not used in position fixing to minimise the atmospheric errors associated with low-elevation signals. Typically set to between 5 and 15 degrees.

Context Preferences

These settings control some aspects of the context-aware components of FieldMap and its interaction with context services. With the exception of the first setting these may be ignored, but should not be changed, unless FieldMap is being used as part of a context aware wireless infrastructure.

• User enter the user name to be recorded as author or editor of recorded FieldNotes.
• Dev
• Desc
• Class
• Local Service Port
• Host
• Start Remote
• Rate
• URL

Notes Preferences

General FieldNote settings:

• Project name the current FieldMap/FieldNote project. This is updated whenever a different map is selected in the Map Preferences page
• Group name the note group name within the project. The group chosen here is used for FieldNotes recording.
• Import Press this button to import the FieldNotes specified in the Project name and Group name fields from a FieldNote format XML file. The button changes colour to a darker grey while the file is being written. On completion, the button reverts to its normal colour. The notes are imported from an XML file (see Export below) to the file
  <installdir>\MobiComp\FieldNote\<project_name>\<group_name>.obj
  Any existing file of the same name is renamed to:
  <installdir>\MobiComp\FieldNote\<project_name>\<group_name>.obj.bak
• Export Press this button to export the FieldNotes specified in the Project name and Group name fields to a FieldNote format XML file. The button changes colour to a darker grey while the file is being written. On completion, the button reverts to its normal colour. The notes are exported from the .obj file (see import above) to the file
  <installdir>\MobiComp\FieldNote\<project_name>\<group_name>.xml
  Any existing file of the same name is renamed to:
  <installdir>\MobiComp\FieldNote\<project_name>\<group_name>.xml.bak
  Exporting to XML files is the recommended method of backing up FieldNotes in a human and machine readable form.
• Note prefix an arbitrary string (max 4 characters) used as a prefix to note identifiers. The only reason to change this is when several users may be creating FieldNotes at the same time, in which case it is advisable to set this string to a different value on each machine.
• Region size (m) notes are pre-fetched within this distance of the GPS location whenever the map scrolls or zooms. 500m is a reasonable setting for most purposes, but may need to be increased when moving rapidly, e.g. in a car on a major road. Some improvement in note loading speed may be gained by reducing the size when moving on foot in regions of high note density.
• Trigger range (m) active range around each note. When the GPS location enters this range, the note is triggered.
• Web page triggered notes appear as a web page. Disable to prevent triggering.
• Once when set, notes are triggered once only, rather than each time they come within range.
• Sound when set, sound an alarm when a note is triggered.
• Edit enable editing of notes ?not used?

Heirport Query Preferences

The Heirport view is part of ongoing experimental work with the Archaeology Data Service to provide mobile location-aware access to ADS and other databases. The view seen in this release is not fully functional and will not be decribed further.

Using a GPS receiver

After selecting Start from the GPS menu, the message at the top of the screen changes to Waiting for GPS. During this phase, the GPS tracker component attempts to open a connection to the GPS receiver

The message GPS Running appears as soon as a connection to the receiver is established. Soon after, the background of the date and time field at the bottom of the screen should change from red to green. This indicates that the time shown is derived from the GPS receiver. A red background indicates a date and time from the computer's internal clock. The GPS time is always UTC, taking no account of local time zones.

The delay between starting the GPS tracker and the appearance of reliable location and velocity data as shown here can be anything from a few seconds to a couple of minutes depending on the acquisition time of the receiver.

The picture gives an example of a good position fix. The first line below the GPS Running message shows the east and north coordinates. The coordinate system in use, in this case the British National Grid, and altitude appear on the second line, and the third line shows the current velocity and heading (in degrees). No heading is shown in this case as the velocity is zero.

On the fourth and fifth lines are details of the satellite constellation and the quality of the location fix. In this example, data is being collected from 7 satellites, the Position Dilution of Precision (PDOP) is 4.0, and the receiver is operating in automatic 3D mode.

In the second picture of the running GPS view, the mode has changed to indicate that a differential correction signal has become available. In this case it is European Geostationary Navigation Overlay Service (EGNOS) test signal from one of the Inmarsat satellites. This service is due to become fully operational in 2004.

The quality of GPS Positioning is dependent on many factors, and may not always be as good as in the previous two illustrations. A 3D fix requires at least four satellites to be visible at the receiver.

Ideally, the available satellites should be spread evenly around the sky in order to provide a geometrically 'good' constellation and minimise errors in calculating the location. The PDOP figure is a measure of the quality of the constellation. The ideal figure of 1.0 is never reached, but anything below 4 is generally considered to be reasonable.

Here, the PDOP has risen above 4, so the program draws attention to the possible reduction in fix quality by showing Poor DOP against a red background in the message area and also turning the background of the PDOP figure red.

With only three satellites, the receiver can only provide a 2D fix. Here, the message area shows 2D Fix against a red background, and both the number of satellites and PDOP have a red background to draw attention to their poor figures.

An altitude figure is still shown but cannot be relied upon as most receivers continue to show the altitude unchanged from the last 3D fix

Here the situation is even worse! The number of satellites has dropped to one and the receiver can no longer provide position and velocity data. The message Not Enough SVs, the coordinates, altitude and number of satellites are now all shown with a red background.

Note, however, that it is still possible to maintain an accurate time signal with a single satellite.

After selecting Stop from the GPS menu, the message area again shows GPS Stopped, but now all of the data remains on the screen. Red backgrounds indicate that this is all out-of-date information.

This screen may also appear during normal running if the connection to the receiver fails. Typically this happens if the computer or receiver are switched off. Under these conditions, the program usually detects the failure after about 30 seconds. It then closes the connection, waits for 5-10 seconds, then restarts it.

Finally in this sequence covering the GPS data view, this picture shows what happens if an error occurs when attempting to start the GPS connection. Instead of the usual Waiting for GPS message, the message area shows Failed to start GPS.

There are several possible reasons why this may happen. Sometimes, the program may simply fail to synchronize with the incoming data, in which case, a second attempt to start is invariably successful. Other common causes include a physical failure such as a cable between computer and receiver, or the receiver has been switched off, or the receiver batteries have expired.

Satellite view when running

When the GPS is running, the satellite view shows information about received signals. It is divided into two panels. The upper panel has summary information on the left including the total number of satellites above the horizon, PDOP, HDOP, velocity and direction of travel. HDOP is the Horizontal Dilution of Precision. It is the 2D equivalent to the 3D PDOP and its lower value indicates the higher precision of horizontal location in comparison with the altitude figure calculated by a GPS receiver.

. On the right of the upper panel is a "sky map" showing the location of visible satellites. North is at the top, the outer ring represents the horizon and the inner ring an elevation of 45 degrees. The centre of the circle is the point vertically overhead. The satellites from which a good signal is being received and which are being used in the position calculations are shown in solid green. Solid red indicates those from which a signal is being received, but which are not yet being used, whilst open red circles represent satellites from which a signal has not yet been received.

. The small blue square in the lower left of the upper panel is an activity indicator. This toggles on and off with each message from an active receiver, and turns red if the connection is lost or no position is available.

. The lower panel shows relative signal strengths for each of the available satellites. Solid green and red bars are used to indicate satellites in the same way as on the sky map.

When the GPS module is running, the map view shows the current coordinates in the message area, updated with each new fix from the receiver. The activity indicator to the right of the message area now shows green, turning on and off with each new fix. If the GPS signal fails or the connection is lost, the activity indicator reverts to red.

. Within the map area, the cursor moves to track the location and, if enabled in the Track Preferences, the recent track is shown as a green line

Creating FieldNotes

FieldNotes may be attached to points, lines or polygons. Point or vertex coordinates may be entered manually, or using the GPS location. Additionally, survey grid units may be recorded using the GPS location, see Recording Survey Grid Units.

The procedures for recording a note are similar whether the GPS or manual input is used. The note geometry is always recorded before completing the note entry form.

First, select Manual or GPS from the Notes menu, then choose Point, Line or Polygon as required.

Manual input:

• The message Waiting for Point is shown, and the geometry input indicator changes to an orange colour. This indicator is a similar size and shape to the GPS activity indicator, but appears at the left hand end of the message area.
• Now, click or tap in the map area at the location of the required point.
• The point is marked on the map and the coordinates appear in the message area.

GPS input:

• The coordinates for a single point, or the first vertex of a line or polygon is captured at the next position fix from the GPS receiver.

In either case, if point was selected, the FieldNote entry form will appear in a web browser window, see FieldNotes Entry Form. If Line or Polygon was selected, continue with the next picture below.

When recording a line or polygon, the geometry input indicator turns orange whenever the system is waiting for a point. The indicator also shows the count of points captured so far.

Manual input:

• Subsequent points are captured as with the initial point by clicking or tapping in the map area at the location of the required point.
• The new point is marked on the map, a line is draw from the previous point to the new point, and the coordinates appear in the message area.
• In manual mode, the indicator always remains orange because the system is ready to accept a new point as soon as the previous one has been entered.

GPS input:

• The geometry indicator turns green to show that the system is idle.
• To request collection of a new point from the GPS, either click or tap on the geometry indicator, or select Add Point from the Notes menu.
• The geometry indicator turns orange, then, when the next GPS location has been captured, it reverts to green and the point count is incremented.

Continue adding vertices in the same way until the line or polygon is complete. Note that there is no need to try to match the final vertex of a polygon with its first, as the polygon will be closed automativally.

After capturing the final vertex of a line or polygon, select End from the Notes menu. For polygons, an final line from the last to the first points is added automatically.

Geometry input may be abandoned at any time by selecting Cancel from the Notes menu.

On completion of geometry capture, FieldMap invokes the web browser and sends a request to the web server to display a new FieldNote Entry Form. The server responds with a template request form.

Select the required template name, or none from the drop-down list and press the New button to request the note entry form.

For more information on templates, see Creating new FieldNote templates.

FieldNotes Entry Form

When the note entry form appears, the FieldNote already includes some information, the project and note group names, a unique FieldNote ID, the name of the author, the date and time or creation, and the recorded geometry.

Note that the form has a reddish colour. This indicates a new note that has not yet been saved.

The picture shows a simple note created without a template. Such notes contain only two editable fields, a text area and a drop-down list of map symbols.

Text can now be typed into the note.

If a template was specified, the template fields may also be completed..

When entry is complete, press the Save button at the end of the note. On a small screen, it is usually necessary to scroll down to find this button.

When the FIeldNote has been saved, the web server returns a copy to the browser with a yellow background. This indicates a note that has been saved previously.

The saved note may be edited. In this example, the symbol is being changed.

After changing the note, always remember to press the save button. However, this is not necessary if the note is not changed.

After saving changes, the revised note is returned. Now, however, it includes additional fields to indicate the name of the last editor and the date and time it was last changed.

It is also possible to add arbitrary fields to a note. To do this, scroll down beyond the Save button to the section Add a new data item. Then enter the field name and value, and press the Add button.

When a field has been added, it appears as an editable text field in the entry form.

When note entry or editing is complete, close the web browser and return to FieldMap.

The new note should appear as a symbol on the map.

Recording Survey Grid Units

New Unit Form

To create a new SurveyGrid note, select GPS.../Survey Grid from the Notes menu. This sends a request to start a new grid unit to the web server. The response, in a web browser window, is the New Unit form shown here.

Select the required template and, if necessary, edit the following fields:

• Unit size the intended length of the unit in metres.
• Left the number of walkers to the left of the FieldMap user
• Right the number of walkers to the right of the FieldMap user
• Separation the distance in metres between each walker

When ready to start walking the unit, press the Start button. This requests a Survey Unit Form from the web server, logs the starting position, and starts a Proximity Tracker.

Survey Unit Form

The Survey Unit Form includes editable fields from the template, and non-editable fields for the values entered in the New Unit Form. These may be completed at any time before pressing the Save button.

As soon as the form appears, the system is ready to record the unit. However, the Save button should not be pressed until the end of the unit is reached, because it also records the finishing position. The recommended procedure is to switch back to the map view so that progress is visible while walking, and to await firing of the Proximity Tracker.

Proximity Tracker

The proximity tracker sounds an alarm and pops up the window shown here when the GPS position detects that the user has covered the unit size distance from the start point. Stop immediately, press the OK button on the pop-up window, and switch back to the Survey Unit Form to complete the data entry and then press the Save button to store the new unit note. The new note will be numbered automatically, and will include the measured distance covered and the bearing as part of the note data.

When the new unit has been recorded, it will appear on the map as a graphic representing the area covered by the walkers. The outermost parallel lines are at half of the walker separation beyond the outer walkers, and represent the limits of the area covered by them.