ESRI Solutions
ESRI has been building GIS software for over 20 years and has been working on Internet services for the past 5 years. The heart of ESRI’s mobile geographic services is a commercial off-the-shelf solution called ArcGIS. This is an integrated family of software products designed to satisfy the needs of desktop, enterprise and distributed GIS users. The overall characteristics of the ArcGIS systems are shown in Figure 2.
ESRI offers both client-centric and server-centric mobile geographic services solutions.
Server-centric solutions
ESRI’s mobile geographic services solutions are based substantially on ArcIMS. ArcIMS is a cross platform application server that is able to perform the following functions:
- Interface to standard web servers
- Utilize many types of geographic data in files and databases
- Broker requests from many clients to provide good scalability
- Process requests for
- Mapping
- Feature streaming (sending intelligent vector objects to advanced clients)
- Geographic and attribute queries
- Geocoding
- Routing
- Data download
- Scale to support
thousands of concurrent requests and millions of
daily requests for services
High-level communication protocols
The low-level telephony protocols described above are concerned with transferring bits of data of a network. Higher-level applications are responsible for creating these data and encoding them in a form that geographic applications, programmers and users can work with. Again.
Client-centric solutions
A second key piece of ESRI software for mobile geographic services solutions is ArcPad. This is a relatively lightweight commercial off the shelf GIS application that runs on Pocket PCs. It is a self-contained application with several important capabilities:
- Out of the box GUI
- Pen-based interface
- Symbolise multiple layer types
- Edit vector objects (points, lines and polygons)
- Edit object attributes
- Interface to a GPS receiver
- Geographic and attribute queries
- Interface to geographic services
- Customisation
ArcPad is able to operate as a completely stand-alone application on a Pocket PC device. It has been widely deployed in applications such as environmental and utility field data collection, transportation navigation, and military map display. It is also able to connect to an ArcIMS server using a wireless modem and take advantage of the ArcIMS services listed above (Figure 4).
In the case of the example configuration shown in Figure 4, ArcPad is responsible for map display, allowing the user to define an area of interest (e.g. by drawing a rectangle on the screen, or asking for the map to be centered at a particular point at a given scale), defining the projection the service should use, and for making an ArcXML request to the server. The server receives the ArcXML request, obtains the data from the database, renders the requested map, clips the map, converts it to a JPEG bitmap, and creates an ArcXML formatted response. When the client receives the resulting map it displays it on the screen.
Real world implementations
Real-time traffic services – these can be broadcast to a number of mobile devices in near real-time. Several organisations are already using GIS for this type of application. See for example real-time traffic conditions in San Diego with actual travel speeds:
Routing – the many uses of
routing services include planning schedules for
service technicians and delivery trucks, devising
routes for large loads that avoid potential
obstructions such as narrow bridges, and personal
routing. RTSe has developed a fully automated
routing service from for wireless devices called
RouteWAP using ESRI’s RouteMAP IMS product:
http://www.rtse.com
.
Tracking or Automated Vehicle
Location (AVL) – interest in fleet management
services is growing fast. Applications such as
m-Track (
http://novovcs.com/),
Air-Track AVL (
www.airtrak.com/home.htm)
PortaTrack by Main Course Technologies (
www.gomct.com
) utilize ArcIMS taking advantage of HTML or Java client viewers to optimise the performance of many operations.
Data collection – more powerful clients are able to perform field-based data entry. In the US Pennsylvania Department of Environmental Protection uses ArcPad in conjunction with ArcIMS and ArcSDE for field-based entry of data about West Nile virus sample data. The West Nile virus is spread by chickens and other animals and can cause human fatalities. Maps showing details of sample locations are downloaded each day to a Pocket PC running ArcPad, data about samples are collected and entered into the system, and then at the end of the day the sample data are uploaded to the main database for management and analysis.
Geographic-based tariffs – setting phone tariffs offers competitive advantage to telephony companies. SignalSoft, an ESRI Business Partner, allows calls in proximity to a customer’s home or office to be billed as part of a flat fee, just as wired calls are today. Adoption of this service will stimulate the replacement of wired phone services with wireless devices. SignalSoft integrates ArcSDE and ArcView into this business-to-business (B2B) service.
These are just a few examples of many applications that are in operation today.
Conclusions
Mobile geographic services is a fast growing field of GIS. Although there is much hype associated with the technology, it is clear that even today technology are finding real business benefits in using geographic information in a mobile context. From yellow pages to routing, to data collection there are many success stories. As the technology improves especially telephone data transfer speeds with the introduction of 3G systems, things can only get better. ESRI has been building mobile geographic services for a number of years based on the well-tried and tested ArcGIS technology. Key aspects of the ArcGIS systems are the ArcIMS application services provider and ArcPad the lightweight mobile GIS client for Pocket PC devices.