April/May 2003

Few mobile logistics and field service applications could exist without digital mapping, but its importance is sometimes underestimated, says Sharon Clancy

Go back ten years, and you'd find that a lot of people in the mapping world were holding their breath, metaphorically if not actually. They were busily digitising their existing mapping to streamline printed map production, whilst simultaneously waiting for the avalanche of third-party software applications that they were sure was looming somewhere round the corner for the new digital maps.

Well, it took a while, but it seems those GIS pioneers have finally been proved right. With the development of faster computers, the advent of the World Wide Web and the emergence of a multiplicity of guidance and tracking systems, digital maps have very definitely shifted from niche to mainstream.

You don't have to look far in the world of logistics and field service to see this borne out. Digital maps have come to play an essential role in planning, especially in routing and scheduling of vehicles and people, and analysis of routes. Digital maps also form the backbone of any tracking operation: latitude and longitude data from GPS systems are superimposed on maps to give a clear picture of exactly where vehicles or mobile workers are or have been.

 

Digital maps also play an essential role in navigation systems. These days you can expect to see quite detailed mapping used in on-board computers or handhelds and PDAs for showing drivers where they are, or how to get to their destination.

So what exactly is a digital map? In essence, it's a version of a map that can be used on a computer. Either it will be basically a picture of a map, cartographically corrected so that coordinates can be placed accurately on it; or it will be what amounts to a textual list of coordinates - something that cartographic software can reassemble into a quite sophisticated map on demand (see panel on page 18).

As digital mapping has come into its own, it has also fallen in price. In the earlier days, map developers didn't want to give away what they saw as the crown jewels of their business. Now, however, the data is becoming more affordable; some suppliers simply offer it as part of a package of fleet or field service management systems. In other cases you might find yourself paying for it on a per-use basis, downloading maps from the Internet as and when you need them.

All the benefits associated with routing and scheduling, for example, are further enhanced when street-level mapping and real-time traffic and navigation data are added. After all, the more familiar the driver is with a delivery point, the greater the contribution digital maps can make to operational efficiency because the less time the driver spends locating the address. The map can be downloaded to the cab either from the office or from an Internet site.

The latest role for digital maps is in location based services. As well as navigation, these provide information on restaurants, petrol stations and so on. Although these are aimed primarily at the consumer market, they also have appeal for mobile workers.

Map providers

There are many providers of digital map data. Some have evolved from a history of producing paper maps, while others have emerged from the digital mapping revolution. Leading players include Britain's Ordnance Survey and Automobile Association, Navigation Technologies and Tele Atlas.

The source of many base map datasets for Britain is, unsurprisingly, Ordnance Survey, the UK Government's national mapping agency. Many people still think of OS as a worthy if slightly staid organisation providing large-scale paper maps for weekend walkers and leisure motorists. It still does that of course, but it has also become a world leader in digital mapping. It began digitising its maps as early as 1973, mainly as a tool for updating its paper maps, and by 1996 the UK was the first country in the world to be completely mapped in digital format, including landscape features, roads and railways.

OS says its prime role is still that of a geographic data gatherer, but it now actively seeks to sell the data to commercial users. Indeed, 75 per cent of its business involves selling digital mapping data, and it works with many partners who use OS datasets in their applications.

A long-standing rival is Britain's Automobile Association, which during the 1980s and 90s developed an extensive range of its own digital maps, drawing in part on out-of-copyright OS data, but also doing new surveying of its own. The two organisations have had a sometimes stormy relationship, but now coexist more harmoniously, and a wide range of map datasets is now available from the AA.

Last year OS unveiled MasterMap, a new digital map of the UK which replaces 230,000 paper maps. MasterMap uses a link-and-node system of referencing for greater detail. So as well as roads and large objects such as buildings, MasterMap identifies millions of non-addressable properties and natural landscape features such as railway signal lights and free-standing letterboxes.

Ordnance Survey describes it as an enormous national jigsaw puzzle made up of 400 million pieces. Each piece is coded with a unique 16-digit reference number known as a topographic identifier or TOID, that identifies both where and what a feature is.

MasterMap is updated frequently; around 5,000 changes are said to be made every day.

Navigable attributes

As with paper maps, the key to digital map usability is to have sufficient information for the purpose without being swamped in unnecessary detail. Tracking systems, for example, can plot vehicle movements on maps of varying scale depending on what is required.

However, for time and distance analysis, and urban or home deliveries to unfamiliar addresses, a useful refinement is adding a layer of what geographers call navigable attributes. These can include one-way streets, speed limits and weights and height restrictions, and make possible address-level tracking, route optimisation and time-and-distance analysis.

"Navigable attributes are critical for accurate drive-time analysis and estimates," believes Andrew Little, marketing director for Navigation Technologies, which is one of the main providers of this very detailed data. NavTech started life developing map data for in-vehicle navigation systems, but now also sells its data widely for GIS applications.

"Basic digital map data will calculate the most direct apparent route," he says, "but data with navigable attributes will show the required driving route based on one-way streets, speed categories and physical, logical and legal turn restrictions. This gives despatchers a real-world representation of the street network and not only facilitates more accurate drive-time analysis and automaticvehicle location (AVL), but also makes possible shorter, more precise delivery time windows."

Vanessa Lawrence, director general and chief executive of OS, agrees that modern mapping systems need to take account of all the one-way systems, no entries, dead ends and traffic calming measures. "If drivers are to bypass incidents, or divert at short notice to pick up that extra load, having the routing information back at the office is no use whatsoever. Taking a diversion of twenty miles only to find a low bridge, a weight restriction or width limitation is not only costly, but also frustrating."

OS has added what it calls an Integrated Transport Network layer to MasterMap. It is an updated version of the OSCAR dataset designed for routing, tracking and logistics companies. It includes driving restriction information, plus an interactive address layer which geo-references around 26 million postal addresses.

Tele Atlas for its part offers a Multinet map dataset, which includes features such as RDS/TMC location codes and signpost information. Tele Atlas is providing the RAC with digital maps for roadside assistance service. RAC's call centre technology can pinpoint the exact location of its customers when they need roadside assistance.

Incidentally, knowing the road system and traffic conditions may be only part of the story. The software may also need to know who it's guiding. Graham Page, UK managing director of location-based services specialist Telcontar, points out: "Your software may have to be able to tell the difference between a driver and a pedestrian, for instance, so that a person on foot is not affected by one-way traffic and can use subways."

Embedded mapping

Digital maps are often embedded in other applications, so lots of companies may be using NavTech, OS, Tele Atlas or other map data without even realising it. AA and NavTech map data, for instance, is used in TruckStops and Paragon routing and scheduling software. Paragon has added NavTech's NavStreets street-level routing for operators involved in urban delivery operations with high drop densities.

Kingswood MapMechanics, which markets TruckStops in the UK, has taken the route-map capability a step further with its Route Reporter function. The combined package not only generates delivery schedules, but also produces local maps of the area around each call point, helping drivers find exact locations easily.

Route Reporter draws on the capabilities of another piece of software, GeoConcept, which is one of the international big names in GIS and computer-based mapping (others include ESRI and MapInfo).

Tele Atlas is another company with a growing presence in the market for embedded mapping. For instance, it supplies its Multinet digital maps to tracking and fleet management giant Minorplanet, and is also a leading player in the emerging market for location based services (for more on LBS, see page 12). It is partnering Hutchinson's Three operation in the 3G mobile phone market, and supplies the maps for the TomTom Navigator application for mobile phones and PDAs.

It is collaborating with navigation specialist Wayfinder to provide mapping for Nokia 60 Series mobile phones. Users enter the destination using the phone's keypad, and the route is downloaded from the Internet or via GSM/GPRS networks.

If you are downloading maps as part of a telematics or tracking service, you might think you're getting them free, but the provider is actually paying an annual licence fee to the dataset producer. Tracker Network, for example, pays £30,000 a year in licence fees for UK street-level mapping, which give it unlimited use of the data. Customers are recharged either on a per-per-use basis or as part of a package. Tracker incorporates ActiveX tools which allow operators to manipulate the map data on the PC rather than download it from the host Web site.

Another mapping user is NetDespatch, which specialises in job booking software for the courier and carrier market, and has integrated Mapquest.com online mapping into its Internet site. It says the benefits for couriers include the ability to price jobs using actual mileage calculations, and get directions to pick-up and drop points.

MapQuest, owned by AOL, is also said to be the world's largest provider of free-to-use online street maps, with more than 20 million a day supplied, although it now competes with many other suppliers such as Maporama and Multimap.

Real-time navigation

Navigation is often predicted to be the next big application for digital mapping. Traffic congestion is expected to get worse in the UK over the next decade, and although the Government is committed to improving the road infrastructure, there will be more delays because of road works. So the levels of service that customers are beginning to expect will be increasingly difficult to deliver.

That's why experts predict growth in demand for on-board real-time navigation systems linked to traffic information; drivers will need help navigating their way round a jam. The mapping data for on-board navigation systems has traditionally been supplied in CD-ROM format, but increasingly there are Internet-based services that offer the appeal of more up-to-date mapping.

One of the challenges in delivering digital maps to mobile devices is the transfer and management of the GIS data. OS MasterMap is delivered in GML format (Geographic Mark-Up Language), the international standard for storing and transporting geographical information, to ensure interoperability. GML is supported by the Open GIS Consortium, and is derived from XML, so is Internet-friendly.

GeoConcept uses a feature called Fast Compressed Mapping to shrink big map datasets to a size more appropriate to transmitting over the Internet or loading on handheld computers. FCM can also make large datasets more practical for use on PCs in tracking or similar mapping applications. Supplier Kingswood MapMechanics says, for instance, it can make it possible to work with the entire OS Landline dataset on a stand-alone PC.

Telmap has developed what it claims is unique client-server technology to make GIS data transfer and management simpler over any type of communication lines or bandwidth. Its Map and Location server acts as an information filter for incoming and outgoing data, handling among other things the conversion of geographical data.

Map data in vector format is transferred to the Java-based Telmap Client which transforms it into dynamic, high-quality maps in seconds. The maps contain advanced applications for display on a wide range of end-user devices such as desktops, laptops, PDAs, cellular phones and an array of other wireless Java devices.

Other suppliers have their own solutions to the data compression issue. Telcontar, for instance, uses compression tools in its Drill Down Server, and sees this as having a key role in overlaying traffic information on mobile maps in real time. "For a traffic application to be truly useful, drivers needs to know about a traffic jam before they get to it so that they can take an alternative route," Graham Page says.

What are digital maps?

Digital maps are created by digitising geographical data. The map can be at various levels of what's called granularity - representing anything from a national road map right down to a detailed street plan.

Digital maps may all look similar, but come in two quite different forms - raster and vector (although in some cases they are a combination of both).

In raster data files, the map is stored as a pre-defined bitmap image made up of an array of pixels. Whatever software you use to display it, it looks like a printed map, and in a similar way it's fixed at a given scale; zooming in and out just enlarges or reduces it.

Vector mapping, on the other hand, stores the map detail as a series of digitised coordinates, and relies on intelligent software to build these into a convincing-looking map. The files are compact, and individual components or layers can be displayed or suppressed by your software, perhaps according to the zoom level. The data can be redrawn at any scale without loss of definition, and mapping software can apply colour to different components.

Some applications overlay vector information such as tracking coordinates on a raster backdrop. Intelligent software can make sense of scales and projections to ensure that the various datasets are kept in sync.

The mapping engines used in tracking and navigation systems often jump automatically from one map dataset to another according to how much detail they have to show, which is why the mapping may change radically in appearance as you zoom in, perhaps going from raster to vector and back.

Getting the raw data in

If the data-gathering that goes into digital mapping sounds labour-intensive, it is. OS, for instance, has 11 regional officers, 60 field officers and 350 surveyors. The surveyors use GPS to pinpoint locations, and handheld pen computers called PRISM to plot changes. Even so, ground staff produce only 50 per cent of all the data gathered. OS also uses aerial photography to check changes in rural areas, and accepts GIS information from other sources including, for example, house builders.

NavTech's target is 97 per cent accuracy, and it aims to drive each road in the UK at least once a year, to verify the database. Researchers check that junction shapes, for example, actually represent what is on the ground. If this sounds a bit obsessive, NavTech says there's no other way to check that the instructions actually mean something to the driver. The database also includes 44 categories for points of information. Data is published four times a year.