MOBILE COMPUTERS FOR FIELD DATA COLLECTION

- SOME PERSONAL REFLECTIONS

Christopher LeggGIS/RS Consultant

In any kind of field work, location of the observation is critical

Before the availability of low-cost portable GPS receivers in the early 1990s, this was a problem in areas without good maps

Field workers often had to rely on air photos, or place names (frequently ambiguous) from local residents

WHERE THE.....

?

Where on Earth are we ?

or

GPS gave the answer to the important question

However, the position from a simple GPS receiver is in the form

32.54321 degrees East, 12.56789 degrees North

This is not very useful by itself

The position must be viewed on a map or satellite image in order to be understood

Positions had to be transferred from GPS to computer to be visualised

Data transfer by writing locations in a field note book and then manually entering at a computer keyboard often introduced serious mistakes

The problem is that these combined data loggers and GPS receivers were very expensive. The example shown on the left was more than US$4000.

By 2000, some distributors of hand-held GPS units were offering sophisticated units which allowed flexible user-defined data collection

Some devices even included laser range-finder, digital compass and camera, providing a total solution in a single unit, and very attractive to utility companies and others managing complex spatial assets.

The first PDA was the Apple Newton, released in 1993, and discontinued in

1998. GPS connections and data collection software developed from

1996. The Newton had a larger screen than cellphones or later PDAs, and

very sophisticated handwriting recognition

The Palm Pilot was released in 1997, and upgraded continuously until the present. With the demise of the Newton, this was the main focus for PDA navigation and data collection

from 1998. Palms had small touch-screens and handwriting recognition

The use of a simple GPS connected to a hand-held computer (PDA) allowed collection of geographically referenced field data. The data to be collected could be chosen by the user, and menus could be written to speed up and simplify data entry.

Tests were carried out in Indonesia with a PalmIIIx hand-held computer using the free StickeSuite software developed by the University of Kent

THE PALM CONNECTION

For use in forest, most GPS units before 2002 needed an external antenna. Connections between GPS and PDA were often complex because of incompatible plugs. The result was a tangle of wires, easily snagged on forest vegetation

A simple database and associated menus were developed for collection of faunal data in the EU FIMP project in Indonesia, and later for vegetation mapping for the Leuser project in northern Sumatera.

The software was further adapted for mapping farmer fields in Cameroon as part of the ASB CamFlores modelling project

First results from Leuser of Palm-Garmin combination

During an overflight of the Leuser Ecosystem on Saturday September 16th, 2000, three Garmin-Palm combinations were used to collect land-cover data in preparation for the production of a new land cover map of the area using recent satellite imagery.

This map shows the data collected. Different forest types are shown in shades of green, oil-palm estates are in purple.

A second flight was undertaken in late October to check the vegetation map

Perennial tree crops

Fallow, forest-fallow and forest

Annual food crops

Awae Village

In 2001 and 2002, thousands of farmer fields, including active fields, cocoa and fallow, were mapped in three villages in Cameroon rain-forest areas using Palm-GPS combinations and Sticke-Pad software

By 2006, hardware had greatly improved. High-resolution colour display, big memory and no cables (Bluetooth GPS)

In 2009, the Great Lakes Cassava Initiative in East Africa requested a field data collection system.

1) To collect complex data on cassava diseases and pests during routine surveys in six countries2) GPS and camera to be integrated with data collection3) Relatively low-cost “off the shelf” hardware and free software4) Data transmission from regional centres to project headquarters through standard cellphone network

At the time, the best options were the HTC TyTNN2 (Windows) or a Blackberry. More software was available at low or no cost for Windows Mobile platforms, so the HTC was purchased for trials.

Since then, HTC phones have improved, and iPhones and Android smartphones might be better options

Google Maps

No data collection, but useful for navigation in areas with good internet connectivity

gvSIG Mobile

A mobile open-source GIS developed in Spain with EU funding. Must be partnered with gvSIG on Windows PC for data transfer

gvSIG Mobile 2

CYBERTRACKER

The most widely-used package for mobile data collection, especially in wildlife conservation.

Interactive data collection forms prepared on PC and downloaded to mobile. Can include photos, and navigation through maps and satellite images

CYBERTRACKER 2

GEODEXY

Commercial software available for free trial, and special licence for development projects. Data collection forms can be customised, data can be sent direct to server. Database in Excel and other formats can be maintained on server, with remote access on smartphone. Company now re-named “All Inspections” , and status of development use under review

GEODEXY 2

A picture can be taken with the internal camera, attached to the geocoded record, and uploaded to the server embedded in the record

GEODEXY 3

Locations of records can be viewed on the mobile device against a background of Google Maps or a pre-loaded shapefile

GLCI has now decided to use Logitech digital pens for field data collection, instead of GeoDexy on smartphones

This is mainly a consequence of user response following field trials.

The smartphone solution was not popular1) Poor screen visibility in sunlit field conditions2) Small screens and difficulties of screen navigation with stylus

Digital pen was selected because1) Paper forms are a very familiar format for field staff2) No problems with poor visibility and fiddly screens

However!1) Use of digital pens still requires separate GPS readings, and problems of errors in transcribing GPS locations to digital pen forms2) No geolocated pictures of diseased cassava3) No direct means of transmitting field data to central office

Novel Techniques for Data Collection and Transmission in

GLCI

Monthly transmission of cassava disease

observations by SMS in Tanzania

Digital Pens for collection of cassava disease data

Training in GeoDexy software on

smartphones for georeferenced field

data collection

Two application developed for geological mapping are SigmaMobile from the British Geological Survey and GeoRover from GAF in Germany

Both depend on the user having an ESRI ArcGis licence, although Sigma hopes to go “open source” during 2011

Sigma uses ruggedized laptops (expensive) while GeoRover uses large-format PDAs for field data collection combined with laptops for field camp use.

NEW DEVELOPMENTS IN DATA COLLECTION

MAPS AND NAVIGATION

Numerous low-cost commercial software packages for the Palm allowed display of maps, usually with connection to a GPS for real-time tracking and navigation.

HandMap software enabled generation of Palm maps from ArcView shapefiles, and navigation using a GPS.

Atlas software enabled conversion of satellite imagery to a Palm-compatible format, and field navigation against an image background.

Long before “Sat-Nav” became common on GPS enabled smartphones, GPS navigation was possible on PDAs

A range of software packages are now available for field tracking on maps or satellite imagery.

Most depend on commercial, usually ESRI, products.

Tango GPS is freeware, but runs only on Linux. High-resolution satellite imagery can be pre-loaded and cached from Google Earth. Shown here in operation in the Afar Depression, Ethiopia

GPS and GOOGLE EARTH

With just a simple GPS unit, and a computer connected to the Internet, field observations can now be displayed at no cost against a background of satellite imagery and maps using Google Earth. Field data can now be shared simply with others using KML files sent by email

Free software (DNR Garmin) can be used to convert GPS data to KML files, which can themselves be further edited using Excel or Open Office

Mobile hardware is developing very fast, with new and improved devices available almost every month

Memory has expanded fantastically, 8Gb “flash” memory being common

Processor speed is now almost as high in mobile devices as in desktops

The big conflict is between compactness, screen size and ruggedness

Most mobile phone users want small size and weight

Rugged larger screen devices will have limited market and thus be much more expensive

It is exciting to try to keep pace with developments, but also good to find a system which works for you, and then to stick with it

HAVE FUN !