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GIS

Spatial Technologies-Software Strategy: Going Mobile

28 Feb, 2005 By: James L. Sipes

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Mobile GIS brings instantaneous information to users in the field.

Traditionally, gis maps had to be printed in order to be carried out into the field. In addition, the process of collecting data in the field was time-consuming and prone to error because we were limited to writing notes on paper maps that had to be translated by a GIS technician. If you live in a rainy place like Seattle, as I do, then you know how much fun it is trying to sort through paper maps without ripping or smearing them. Trying to read smudged notes is also a lot of fun.

Figure 1. For field work, PDAs tend to be more durable, smaller and easier to handle than laptops. They also have batteries that last longer than those of regular laptops. Image courtesy of Maptech.

One approach that gets rid of the problems with paper maps is mobile GIS, which completely changes the way geospatial information is collected. Mobile GIS technology gives users the ability to access geospatial data from virtually anywhere in the world. It's also one of the more efficient ways to collect data and to field verify information because results are typically much more accurate than trying to use paper maps.

The quality of a GIS database is only as good as the quality of its data, and the use of mobile GIS can result in better data, and ultimately a better GIS database. By being able to connect with a GIS database, a field crew can access any maps or information they need to solve the problem at hand.

Why Use Mobile GIS?

Most mobile GIS users have already implemented GIS in their offices. It's no surprise that many of the larger companies and organizations that have adopted enterprise GIS already use mobile GIS technology extensively. Mobile GIS is a logical extension of an enterprise GIS. However, larger companies are not the only ones taking advantage of mobile GIS. The cost of mobile GIS has dropped to the point where even smaller businesses are using the technology in their day-to-day businesses. A big benefit of mobile GIS is the ability to collect data from any location and then store that data in a centralized spatial database that can accessed by others. This approach helps to ensure that everyone in an organization is working with the same information because any changes in the field are immediately incorporated into the GIS database.

Different industries and organizations are still figuring out how mobile GIS technology fits into their operations. Virtually any task that involves field data collection or mapping can benefit from the use of mobile GIS. An insurance adjuster can help identify the exact location of an accident, a zoning inspector can immediately access the codes for a specific location and a police dispatcher can identify the closest unit to the scene of a crime. An EMS dispatcher can tell ambulance drivers the best way to get from where they are to a home or to the nearest hospital. A wetlands biologist can delineate the edges of a wetland while in the field. For a recent project, we used mobile GIS, portable GPS units and laptops to identify unique wildlife habit areas in the field.

Utility companies use mobile GIS to help field crews locate structures on the ground more quickly and to report any changes in the utility infrastructure. Service-oriented industries such as florists and shipping companies are using mobile GIS to get to their customers more quickly than before. A customer service representative can give disgruntled homeowners a better idea of how long before their electricity is restored or their cable TV is up and running.

Many municipalities are also extensively using mobile GIS. Santa Monica is one of many cities that has implemented mobile GIS to meet the day-to-day needs of managing a city. The city runs ArcView on desktop computers and ArcIMS tools on its intranet and Internet, and city staff uses ArcPAD on Compaq iPAQ Pocket PCs running Windows CE to access GIS information while out in the field. The primary use of mobile GIS is to update the City's core geographic information, but custom applications are also being developed for city departments with specific needs.

The increased popularity of mobile GIS is due in large part to technological improvements in GPS technology to help identify your location in the field, wireless communication technology for sending and receiving data, and handheld or laptop computers that are rugged enough to take outside. We have also seen an increase in the quality and variety of GIS software for accessing and modifying maps and inputting data.

Figure 2. Location-based services are used to make it easier to navigate from one place to another. Maptech's i3 Touch Screen can be used with Marine Navigator. Image courtesy of Maptech.

GPS Technology

GPS (global positioning system) uses satellites to determine precise locations on Earth. There are 24 GPS satellites orbiting the Earth, and GPS receivers use them to determine the exact latitude and longitude of a location. These satellites transmit a constant data signal, and any device that can tune into the frequency of the satellite can receive the signal. The GPS receiver picks up a digital signal transmitted by the satellites and measures the time taken for the signal to arrive. Typically, a minimum of four satellites are referenced to calculate a position. The more satellites that are referenced, the greater the level of accuracy a GPS unit can achieve. The major limitation is that there must be a free line-of-sight, so most GPS receivers don't work indoors in obstructed areas.

One GPS system you may have heard of is the WAAS (Wide Area Augmentation System), which is a system of satellites and ground stations that provide GPS signal corrections. The basic idea behind WAAS, developed by the U.S. Federal Aviation Administration and Department of Transportation, is to provide a greater level of position accuracy for air, marine and land-based uses. A WAAS receiver typically can provide accuracy of better than three meters by correcting GPS signal errors that are caused by ionospheric disturbances, timing and satellite orbit errors. WAAS is currently available only in the United States, but other governments are developing similar satellite-based differential systems.

Among the more popular manufacturers of GPS receivers are Garmin, Trimble and Ashtech/Magellan. Each offers a wide range of receivers to choose from, depending on your individual needs. For example, Trimble manufactures a number of GPS receivers, including the GeoExplorer Series, the GPS Pathfinder Pocket and the Recon Series. Trimble GPScorrect provides differential postprocessing capabilities for ESRI's ArcPad. It integrates control of a GeoExplorer series handheld or GPS Pathfinder receiver into ArcPad.

When selecting a GPS unit, we also look to see if it offers differential correction capabilities that can improve the accuracy of GPS positions. For example, a differential GPS can increase accuracy from 5 or 6 meters to less than 50 centimeters, depending on the type of GPS unit you use. Trimble GPS Analyst is an extension for ArcGIS that can differentially correct GPS data directly inside ArcGIS, and it offers a seamless workflow for ArcPad.

Portable Hardware

Selecting the best hardware for mobile GIS applications is based in large part on size, cost, durability, battery life and ease of use. Hardware must be easy to use, hold up even in windy or dusty conditions and have a long battery life.

For complex projects that require the full functionality of ArcGIS, users need a laptop or Tablet PC. I am a big fan of using Tablet PCs for mobile GIS. Users can input data with a digital pen instead of a mouse, and digital ink technology makes it possible to create georeferenced notes or sketches that can be tied to a specific map. ESRI's ArcMap, for example, includes a toolbar that integrates digital ink technology with ArcGIS.

Figure 3. With MapTechs Terrain Navigator Pro, users can view topographical maps side by side with photos or quadrangle maps.

One potential problem with laptops is that glare from sunlight can make it difficult to see the screen. As a general rule of thumb, most laptops don't withstand the wear and tear of being in the field. Some of the more common problems include hard drive failures and broken hinges where the monitor connects to the laptop unit. New "ruggedized" laptops are supposed to be more durable, but these still have problems with durability.

Another approach is to use a handheld computer such as a Palm or Pocket PC (figure 1). After breaking the hinges on my laptop twice, I left it at home and purchased a Palm computer. Handheld computers, also referred to as PDAs (personal digital assistants) are small, have long-lasting batteries, are easy to read even during the sunniest days and are much more durable than laptop computers. A potential downside is that the small size of the screens can make it difficult to see detailed maps, and users may spend a lot of time panning and zooming to find the right map location.

In recent years, there have been significant improvements in cell phones with Internet and GPS capabilities. With a phone such as the Nextel i88, users can access Web-based maps and use navigation software to help get from one place to another.

Regardless of the type of hardware, users must be able to handle the data. Either they need sufficient disk storage space on the handheld computer to store the data needed, or they must have sufficient bandwidth to send and receive data in real time. We prefer handheld computers that have some type of nonvolatile data storage because RAM is not secure. If users drop the handheld or accidentally turn it off, the data is lost.

Wireless Technology

Wireless technologies are used extensively in most mobile GIS applications because they allow users to instantly access information from a centralized GIS database, and any changes or additions are immediate. The most popular mobile GIS software and hardware uses wireless technologies to send and receive data from virtually any location.

Currently, mobile GIS hardware devices rely on either GPS or cell towers to determine their location in the field. The advantage of handheld computers and mobile phones that use cell tower systems is that they can operate within buildings. Several mobile phones on the market offer GIS capabilities, but we'll have to see if mobile phones become the tool of choice for GIS users. GPS technology, however, currently offers the best accuracy and is by far the most popular technology for mobile GIS.

Two wireless standards that are influencing mobile GIS are the WAP (wireless application protocol) and WML (wireless markup language). WAP works across differing wireless network technology types and can be used by handheld digital wireless devices. WML is a markup language based on XML that is used for defining content and user interfaces for narrowband devices such as cell phones.

In This Article

GIS Software

The software for mobile GIS provides traditional GIS functionality such as map navigation, layering, querying, data capture, editing, hyperlinks and displaying vector and raster images. Many of the mobile GIS programs are based on Microsoft's Windows CE because it's considered by many to be the de facto standard for field devices. Most of these programs are based on OpenGIS standards, so it's easy to share data.

ESRI's ArcPad is used in mobile GIS and field mapping applications that run on portable computers such as Pocket PCs, handheld computers and Tablet PCs. It supports a multilayer environment and provides users with mapping, GIS and GPS capabilities. ArcPad provides support for industry-standard graphic display, map navigation, data query and simple GIS tools. Editing tools allow users to create, move and delete line, point, and polygon features in shapefiles. Data entry forms can be used in the field to record attribute information.

ArcPad supports both vector maps and raster images such as aerial photographs and satellite imagery. Some of the standard formats that ArcPad works with includes ESRI shapefiles, MrSID compressed images, BMP, JPEG, PNG and Arc IMSImage Services via the Internet. ArcPad offers integration with an optional GPS or DGPS (differential global positioning system). A number of templates available for ArcPad are geared for specific industries. These vary from tools to applets to forms, but all are designed to make the job a little easier.

ArcPad's Application Builder is a development framework for building custom mobile GIS applications. It provides additional tools that can be used to customize the program. A fully functional trial version of ArcPad is available, but it has a 20-minute session time limit.

MapInfo's MapXtend is used to develop location-based GIS applications for wireless handheld devices. It's an extension of MapXtreme, which is MapInfo's map server. Applications that are developed with MapXtend's Java technology architecture can be run on different servers and mobile devices, and this gives companies a lot of flexibility on how they use mobile GIS.

FieldWorker Enterprise is a powerful, easy-to-use program for mobile data collection. Autodesk OnSite combines MapGuide Web software and Oracle 8i (and Oracle 8i Lite) to manage maps, data and design drawings while in the field. MapFrame's FieldSmart is a combination of mobile mapping and field automation software. The FieldSmart Mobile Suite includes the complete set of FieldSmart applications: Sketch, Collect, Inspect, Repair, Design, Route and Secure. The FieldSmart product line, each of which can be purchased separately, is based on the core map viewing capabilities of FieldSmart View.

Location-Based Services

LBS (location-based services) is a growing technology industry that focuses on providing GIS and geospatial information-portable hardware. Currently one of the biggest uses of LBS is as a navigation tool, such as in-vehicle navigation. Most of the major car manufacturers provide, in at least a few of their models, in-vehicle systems that include a built-in GPS system and a navigation screen on the dashboard (figure 2). Some systems include a voice system that tells drivers where they are, where to turn and when they arrive.

A number of applications are geared toward navigation. FUGAWI is a navigation and mapping system that works with most popular handheld GPS receivers and handheld computers. FUGAWI Marine ENC adds the ability to navigate with vector marine ENC charts, which are available at no charge on the Internet from NOAA and the U.S. Army Corps of Engineers. FUGAWI SkyView UK is stand-alone GPS software packaged with full-color seamless air photos, Ordnance Surveys and maps for England and Wales. FUGAWI Tracker is used to track vehicles, boats, planes and people. Tracker can also be used for GPS navigation for outdoor recreational activities such as hiking, skiing, fishing and hunting.

IntelliWhere is a LBS site from Intergraph that provides both product and service information. LBSZone and LBS Portal also focus on location-based services and technologies. MapInfo Mobile is a LBS page from MapInfo. TripPilot provides access to a large archive of digital maps and includes GPS support and routing features to let users find the easiest way to get where they need to go. CityPicks features recommendations for the best restaurants, bars, nightlife, shops and hotels in selected cities. Users purchase and download the guides to a handheld unit.

MapQuest, the popular online mapping program, can be downloaded to a Palm handheld computer and viewed with AvantGo. CelestNav turns a PalmOS handheld into a full-featured calculator for celestial navigation. It includes a perpetual nautical almanac for navigational stars as well as the Moon, Sun and planets. It can also compute fixed positions from celestial observations, use Mercator and Great Circle sailing computations, and compute the range, height and sextant angle for lighthouses and other terrestrial objects.

Maptech produces a number of mobile GIS products, including navigation programs for land and sea. With Terrain Navigator Pro users can view topographical maps side by side with aerial photos or USGS quad maps (figure 3). It also includes a free ArcGIS 9.0 Extension so you can work directly with GIS data in ArcGIS. Marine Navigator is a marine navigation system. It includes Digital ChartKit, Contour 3-D Charts and Offshore Navigator, and is able to integrate data such as NOAA charts, 3D charts, aerial pictures and navigation photos.

Maptech's i3 module is a high-resolution 3D fish finder that includes a touch screen that can be used to control the entire system. Users can access NOAA charts, overlay radar images on charts and photos, receive weather data and communicate via e-mail, fax and phone. However, more importantly, users can literally see the undersea world in real-time 3D, including individual fish that are sorted by size. This is one of those cool tools that anglers have dreamed of—and fish despise.

Ready To Go

Mobile GIS technology is available now, and every new application that comes on the market seems to improve in terms of power, efficiency and convenience. Years ago, any discussion about computer technology included a reference to a paperless society, but that hasn't happened. Mobile GIS is one technology that may make it a reality.

James L. Sipes is the founding principal of Sand County Studios in Seattle, Washington.