Geographic Information Systems(GIS) is an intelligent map which is a vector or raster produced graphical map which contains polygons, usually parcels which are linked to an intelligent relational database.
Geographical Information Systems, are of considerable use to many people and organizations; and may well be of use to you. But it must be remembered that GIS is itself only a set of tools to be applied by people and it is people who solve problems. So what is important to understand is how you will solve your organization's problems with its help.
A Geographical Information System is a software application that is designed to provide the tools to manipulate and display spatial data. It is effectively a way of computerizing maps. It goes further than that by being able to accept, organize, statistically analyse and display diverse types of spatial data that are digitally referenced to a common co-ordinate system. Each set of data is grouped together in an overlay and new data sets can be produced by combining a number of overlays.
GIS is hard to define precisely as it may be seen as operating at a number of levels, and will mean different things to different people. To some, GIS is a set of software tools that is used to input, store, manipulate, analyse and display geographical information.
To others, GIS may be a philosophy, a way of making decisions within an organization where all information is held centrally and is related by its location. This is a more strategic definition.
A successful GIS may not be an off-the-shelf solution to your problems and will require considerable thought for a successful implementation.
A GIS is a system of three interconnected components, each equally important and necessary to its success. These components are spatial data, software/hardware tools, and a specific problem or objective. Top

Whether yours is a small business, a multinational conglomerate, a government department or local authority, you can bank on two things: a lot of your information will be geographically referenced, and the more information you have, the harder it becomes to manage and interpret. It is a fact that up to 70% of all information in circulation possesses a common denominator: geography. In this case, GIS is important to you because it helps you make decisions based upon geographical information. Unlike any other type of information handling tool, GIS can understand the concept of location.
Consider, for example, a system which enables its user to combine and manipulate demographic, lifestyle and other customer-related data to quite literally pinpoint areas of untapped business opportunity.
A supermarket chain may choose the location of a new store by modeling Shoppers' behaviour using a GIS. This might use information obtained from the population census and from the supermarkets experiences in other locations. A local authority might store the locations of its street furniture with a GIS, and may use the GIS to select those lamp columns which need maintenance. Alternatively, it may be used to identify all litter bins within five minutes walk of the proposed site of a hamburger restaurant.
GIS has taken off in a big way over the past two decades. Moving from the realms of academic research, the technology was first harnessed to the needs of large, information-hungry organizations such as local authorities, environmental agencies, emergency services and utilities providers.
More recently, GIS has leapfrogged onto the back of advances in desktop computing to find application in every conceivable area of business activity. And it is here that the logic of GIS is impeccable, given that competitive advantage is ultimately about delivering the right product or service to the right place at the right time.
World-wide figures for GIS investment speak for themselves. Global revenues from GIS software sales alone are growing at an annual rate in excess of 13% and are likely to top the $1.3 billion mark by 1997, according to research company Dataquest. Top

Here is a list of how other organizations are using GIS, and which you may be able to relate to something which could be of benefit to your own organization:
Retail
Most new out-of-town supermarkets are sited with the aid of a sophisticated GIS. The GIS is used to store socio-economic details of possible customers within the proposed area. A catchment area for a store may be developed by calculating the drive-time - the time it would take to drive to the store's location - and by modeling the influence of competing stores. GIS is also used for facilities management and routing of deliveries.
Utilities
The utility companies are amongst the most active GIS users; GIS is used to build asset databases which often form a central part of their IT strategies. Vector GIS commonly dominates in this sector, extensive use being made of modeling functions which are used to test the response of the network to demand fluctuations. The largest application in utilities is in the area of Automated Mapping and Facilities Management (AM/FM). AM/FM functions are used to manage the plant of the organization, such as the location of cables, valves, customer boxes etc. This application demands up to the minute accurate large scale mapping in digital form.
Environment
As some of the earliest users of GIS, there are many mature applications within organizations interested in environmental data. At the simplest level GIS is used as an inventory of environmental information, for example the location and attributes of forest stands. More complex applications use the analytical capabilities of GIS to model environmental processes such as soil erosion, or the response of a river basin to a large rainfall event. As the data collected often relates to areas and complex analytical functions are common, the raster data model tends to predominate.
Local Government
Local government is one of the largest application areas for GIS, as it is one of the largest users of spatial information. All areas of a local authority may benefit from GIS. GIS may be used in land searches and planning control, replacing existing paper records. Local authorities may also use GIS for property and highways maintenance. GIS may be used in command and control centres for monitoring the emergency services.
Health care
In addition to the asset management tasks in which GIS is commonly used, the analytical capabilities of GIS may also be used in health care applications. GIS may be used, for example, to identify the fastest route between the current location of an ambulance and a patient, based on a database of road conditions. GIS can also be used as an epidemiological tool to analyse the outbreak and spread of illness and disease within the community.
Transportation
GIS has considerable potential for applications in transportation. The planning and maintenance of a transport infrastructure is an obvious application area, but there is now increasing interest in innovative technology such as in-vehicle navigation, and electronic chart displays. These typically require GIS in a support role.
Financial Services
GIS is used in the financial services sector in much the same way as in retail applications. It is used to locate new branches of Banks and Building societies. GIS is increasingly being used as a profiling tool for risk assessment and insurance purposes, identifying in greater detail those areas of highest/lowest risk. This requires databases as diverse as crime patterns, geology, weather and property values.Top

Having settled on your objectives for a system, the next step is to decide on an appropriate product and produce a plan for implementing it. A daunting task in the implementation of any GIS is the collection of appropriate data. Existing data within a organization may have to be digitized. There are now an increasing number of vendors of digital data suitable for GIS. You must be sure that the data is suitable to your particular application.
Spatial data is information which is linked to a specific location, for example the population of a town, or the occupant of an address. In many cases the difficult part of setting up data for a GIS is linking information to a location; a process known as geocoding. Within a particular data set there must, of course, exist an element which specifies its location. Ideally this would be a map co- ordinate, but it could also be a postal code or street address. The element within the data that identifies the location is known as its geocode. A comprehensive understanding of the nature of geographical information is crucial in the data collection process and for the success of GIS as a whole. You will need to address the following questions: Are you aware of the consequences of bringing together datasets collected at different scales ? How accurate are the locations of features such as roads on small scale datasets ? Data sets can be divided into those about people - socio-economic - and those concerning the environment.
Socio-economic data Socio-economic data is widely available, often from national and local government, and is usually the product of population surveys and censuses. This data is also used by a number of commercial vendors who combine census information with other datasets to produce neighbourhood profiles classifying particular areas for marketing purposes. This ability to recognise particular markets based on geographical datasets is known as Geodemographics and is one of the fastest growth areas within GIS. Environmental Data The collection and analysis of information about the environment was one of the driving forces behind the development of GIS and continues to be an important application area. Environmental data sets often tend to be large and require considerable management. Sources of environmental data include: Existing topographic maps, Thematic maps, specifying geological aspects and soils etc., and Remote Sensing, which is gathered from satellite observations and aerial photographs. Environmental data often includes boundaries between vegetation types, for example, which are fuzzy i.e. they are not defined by a simple line. Conversely, socio-economic data is usually related to administrative boundaries, which are sharp if artificial. Top

Data Model

You will need to make a decision over the type of data model you wish to use - Raster or Vector - and it is important to realise that a particular data model may be better suited to your application. However, the choice of data structure you can use for any particular application is often an arbitrary decision, since GIS software will generally support one particular model as fully as another. Data structure is a logical arrangement of your data in a format suitable for you and your system to manage it. Whichever model and structure you choose, you will, of course, need to convert the data you already have into a format which can be used by the GIS. Converting data into digital format is a labour-intensive activity, and can account for up to 80% of the total system cost. Time spent on fact-finding and planning is time well spent. Central to any data capture plan is a thorough internal data audit. This will help you determine the size, scope and cost of the task ahead. Given that few organizations are able to re deploy staff to tackle a data capture exercise, two realistic alternatives remain. Either you can hire, train and equip a dedicated team, or contract the job to a specialist bureau. The latter will almost certainly be able to undercut the in-house option, but you need to ascertain that this will not be at the expense of quality control and flexibility. Data capture can also be an opportunity to improve the quality of your data by incorporating new information with the old.
You also have a choice to make between methods of converting your data: scanning and vectorisation. Scanning offers ease and speed, but the resulting raster images lack the intelligence needed for vector-based GIS. A fair degree of operator expertise is also required, and compression techniques (typically run-length encoding) will need to be applied to keep the files to a manageable size. Vectorisation can be applied automatically or interactively to produce intelligent vector files. Table digitising has the advantage of employing inexpensive digitising equipment. However, operator training is needed to obtain good results, especially from indifferent originals. Conversely, the procedure is laborious, time-consuming and, hence, costly. Other possibilities such as raster-to-vector conversion and pattern recognition are worth considering in this trade-off between productivity, cost, quality and usability. While scanning and table digitising will accommodate the bulk of conversion needs, from text documents to line art and even video images, special techniques have been developed to enter material from other sources. These range from simple programs that facilitate the keyboard entry of survey co- ordinates to techniques that reconcile aerial photographs with base maps. Photogrammetric, remotely-sensed and CAD-generated data represent yet further potential input sources. Top

GIS has generated its own jargon-rich language, which I'm afraid we all fall into at times. So to aid you, below is a comprehensive guide to the jargon of GIS.

Address Matching: A geocoding process which matches the street address of property to its location. This usually involves the matching of two database files, one containing the addresses of interest, the other a list of addresses and their co-ordinates. Address matching is central to many applications in direct marketing.

AM/FM Automated Mapping/Facilities Management:. This is a specific application of GIS to the management and production of maps of plant such as cables, pipes, valves etc. It is currently the most widely used application of GIS, and particularly relevant to local authorities and utilities.

ASCII: American Standard Code for Information Interchange. A standard set of codes which represent alphanumeric characters stored as a single byte value. For example, using the ASCII code, a byte containing the value 69 would represent the letter E. Because of its simple nature, ASCII text is one of the best ways of transferring information between different programs and platforms.

Attribute: An item of text, a numeric value or an image that is a characteristic of a particular spatial entity. Buffer A zone of user-specified distance around a point, line or area. The generation of buffers to establish the proximity of features is one of the most common forms of GIS analysis. For example, it may be used to find all areas of industry less than 5km from a reservoir.

CAD: Computer Aided Design. Software programs for the design, drafting and presentation of graphics. Originally designed for manufacturing drawing, now also widely used for mapping.

Cadastre: A data set containing information related to land ownership and rights. This usually takes the form of maps and descriptions of uniquely identifiable land parcels. For each parcel, legal information such as ownership, easements and mortgages are recorded.

Cell: The basic element within a grid or raster data set.

Centroid: The centre point of a polygon, often used to attach attribute information to an area such as a census ward. The centroid may be mathematically derived (such as the centre of gravity) or may be user defined. It must always be placed inside the polygon.

COGO: CO-ordinate GeOmetry. Algorithms for handling basic two and three dimensional vector entities built into all surveying, mapping and GIS software. Co-ordinate Numbers representing the position of a point relative to an origin. Cartesian co- ordinates express the location in two or three dimensions as the perpendicular distances from two or three orthogonal axes. Data Model A generalised, user-defined view of data representing the real world.

DEM: Digital Elevation Model (or Terrain Model). A data model used to represent a topographic surface, often based on a grid with a height value for each cell, or on a set of irregular triangles (see TIN).

Digitising: Conversion or encoding of existing maps from an analogue form (paper) into digital information, usually in the form of Cartesian co-ordinates. This may be via a digitising table or tablet with a hand-held cursor, or via a scanner.

DXF: Digital eXchange Format A data format defined by Autodesk originally for the transfer of data between CAD systems. Due to its simplicity, it is now widely used in the transfer of data between GIS, despite a number of limitations.

Gazetteer: A list of spatial entities held in computer form, such as properties or streets, which allows for rapid search and query. The gazetteer often forms the core of larger GIS-based applications such as LIS.

Geocode: The element in a database used to identify the location of a particular record, for example a postcode. The process of geocoding is similar to that of address matching, in that a data file is compared against a file of geocode and their associated co-ordinates.

Geodetic Datum: A set of parameters defining co-ordinate systems for all or parts of the earth. These datums have been refined and revised over time. NAD 27 is the North American datum for 1927, for example. ED50 is the European datum for 1950, and WGS is the World Geodetic System for 1984. Varying datums are used to produce better local ëfití of a spheroid (a ësquashedí sphere) to the actual shape of the earth - the geoid.

GPD Global Positioning Systems. A position-finding system which uses radio receivers to pick up signals from four or more special satellites (there are 24 in orbit) and compute WGS co- ordinates for the receiver. Accuracy depends on the sophistication of processing and the time available for reception. Real-time navigation using GPS on aircraft and ships can be to better than 100m. Processed data from several hoursí observation can provide relative positions accurate to a few centimetres.

GUI: Graphical User Interface.A method of interaction with a computer which uses pictorial buttons (icons) and command lists controlled by a mouse. It is generally regarded as simpler and easier to learn than command line interfaces, where commands have to be typed. Examples include MS WINDOWS for PCs, Open Look or MOTIF for workstations and System 7 for Macintosh. Grid Data A data structure composed of square cells of equal size arranged in columns and rows. LIS Land Information System. A subset of the geographic information industry that is dedicated to the management, analysis and presentation of information relating to land, including ownership and legal rights. Often an automated development of the Cadastre.

Latitude-Longitude: A spatial reference system for the Earth's surface. Latitude is an angular measurement N or S of the equator, longitude is an angular measurement E or W of the meridian at Greenwich, UK.

Macro: A series of program commands or instructions which are stored in a file and can be recalled when necessary. Macros are commonly used to customise high-end GIS toolkits for individual applications.

Map Projection: A mathematical model used to convert three dimensional reality into two dimensions for representation on a map, or within a two dimensional GIS database. All map projections have particular strengths, some preserve shape, other preserve distance, area and direction. All projections have limitations, however, of which you should be aware.
Map Scale: The measure of reduction between the representation and the reality, be it a map or a spatial database. Scale is usually represented as a representative fraction of distance e.g. 1:50,000, one unit of distance on the map representing fifty thousand units in reality. The nominal scale of a spatial data set has considerable influence over the possible application of the data set, and you should always be aware of any such implications. For example, it would not be sensible to compare the shape of a road represented in a 1:625 000 scale data set with one of 1:1250. Theoretically, a dataset does not have a scale (unlike a map) but the terms Scale is usually used as a metaphor for resolution and content. Multispectral Remote sensing in two or more spectral bands.

Network: A model representing the interconnected elements through which some form of resource can be transmitted or will flow. In GIS this is represented as a series of nodes connected by arcs, each or which has attributes representing flow characteristics e.g. a road or pipeline network.

Node: A basic spatial entity within the vector data model which represents the beginning or end of a segment. Also, a node may be formed when a number of segments join. For example a node might be represented in a road network as a highway intersection.

Operating System: A series of computer programs which control the operation of the computer itself. Application programs such as GIS software run under an operating system. Examples of operating systems include UNIX, VMS, DOS and OS/2.

Peripheral: A hardware component which is connected to a computer to perform specialist functions. Common GIS peripherals include plotters, digitising tables, and printers. When selecting GIS software it is important to ensure that it is compatible with any existing peripherals you use.

Pixel: A picture element of a raster image as displayed on a screen or raster plot.

Point: A spatial entity that represents the simplest geographical element. Represented in the vector data model as a single x,y co-ordinate, and in the raster as a single cell. The point may have associated attributes which describe the element it is representing; the telephone number of a public call box, for example.

Polygon: A representation of an enclosed region defined by an arc or a series of arcs that make up its boundary. Polygons may have attributes describing the region they represent, such as the population of a census ward.

Quadtree: A data structure that subdivides any given space into four quadrants and continues to subdivide each quadrant in a similar way until they are uniform or the basic resolution of the data is reached. It is mostly used to compress raster data.

Raster: A data structure composed of a grid of cells. Groups of cells represent geographical features; the value in the cell represents the attribute of the feature.

Relational Database: A database which structures data in the form of tables. Each table contains information relevant to a particular feature, and is linked to other tables by a common value. For example, two attribute tables could be linked to a spatial data table via a geocode, such as the postcode.

Remote Sensing: The science of acquiring information about the earth using instruments which are remote to the earth's surface, usually from aircraft or satellites. Instruments may use visible light, infrared or radar to obtain data. Remote sensing offers the ability to observe and collect data for large areas relatively quickly, and is an important source of data for GIS.

Resolution: The resolution of a digital dataset expresses the size of the smallest object which can be depicted. The term is most commonly associated with the raster data model where the resolution of a raster or grid is equal to the size of the cell in the real world. For example, the resolution of a remotely-sensed image may be 10m (each cell representing 10mx10m on the ground). Increased resolution leads to larger storage requirements, increased processing and higher costs for a given area.

Rubber Sheeting: A process which adjusts the relative positions of features within a data set in a non-linear, or non-uniform way. It is used to transform the co-ordinates of maps with different scales, orientation or co-ordinate systems. Run-length Encoding A data compression technique which encodes a digital data stream in terms of the number of successive digital data elements of the same value, rather than repeating every data value.

Scanning: A data capture technique which digitises information from paper or film hard copy into digital raster data. The process is rapid, but the resulting raster data set only has colour, grey scale or black and white attributes associated with it, and may not have the intelligence necessary for GIS analysis. In effect, the result of scanning is a raster image of the original source material.

Segment: One of the basic spatial entities, and a basis for spatial models. Formed from a set of ordered co-ordinates (vertices) that represents the shape of a geographic object. An arc begins and ends in a node.

Spatial Analysis: Spatial analysis is the process of applying analytical techniques to geographically-referenced data sets to extract or generate new geographical information. Spatial analysis may be used to model complex geographical interactions, and is useful for investigating site suitability and predicting future events. Although the overall analytical technique may be complex, it is usually a combination of simple techniques applied in the appropriate order.

SQL: Structured Query Language. A language developed by IBM in the 1970s for defining and manipulating relational databases. It has since become the industry standard, and is often used to enable GIS toolkits to access the data held in existing corporate databases.

Thematic Map: A map which communicates a single theme or subject. For example, a population density map and political boundary map are both thematic maps. This contrasts with a topographical map which is a general purpose map containing landscape features such as rivers, roads, landmarks and elevation.

TIN: Triangulated Irregular Network. A method of creating a surface from point data in the vector data model. The TIN is created from an arbitrary distribution of points joined to form triangles. Each point has an x and y co-ordinate and one or more attributes (e.g. height). Attribute values for a point anywhere in the model can then be interpolated .

Topology: The relationships in spatial terms between connected or adjacent geographical objects. Topology is used to apply intelligence to data held in the vector data model. For example, topological information stored for an arc might include the polygon to its left and right, and the nodes to which it is connected.

Vector Data: A data model based on the representation of geographical object by Cartesian co- ordinates, commonly used to represent linear features. Each feature is represented by a series of co- ordinates which define its shape, and which can have linked information. More sophisticated vector data models include topology. Top

When most people think of GIS, they are actually thinking of GIS software running on a computer. The choice of GIS software and the hardware to run it on is very important, and mistakes can be costly. Choosing these tools used to be simple. There were few vendors of GIS software, and the hardware required to run it was powerful, often specialised and very expensive. The software offered many levels of functionality, was very complex and generally user hostile!
Recently, the market has changed dramatically. There is now an enormous range of software which is labeled GIS and which is available for almost every computer platform. In particular, there has been a divergence into two camps; the high-end GIS and the desktop mapping/GIS package.
The high-end GIS is a development of early GIS software; very powerful, fully functional GIS toolkits which usually require powerful UNIX-based workstations. They provide all the functions you would require for most applications. Data input tools, for example, provide the ability to capture data from existing paper maps and records, from existing digital data and primary data collection methods such as surveying and GPS.
These systems also carry out the management of very large databases, with many users making individual changes. This is an extremely complex process, even with the appropriate tools. The efficient storage of complex spatial data sets is another problem which requires specialised software tools; a comprehensive suite of data archiving tools in particular. Analysis of the geographical information on a high-end GIS ranges from a simple query of the data set, to the creation of buffers and the combination of data sets to create an environmental model.
The presentation of the contents of a spatial database or the results of complex spatial analysis have often been overlooked by the designers of GIS software. Tools for producing cartographic output or sophisticated reports are essential for many applications.
The high-end GIS is really only a set of programs and will often require customization for a particular application. Customization may include the development of Graphic User Interfaces (GUI) and also the development of specialized tools relating to a particular application. As might be expected, such complex software requires considerable support from trained staff.
A major development in the GIS software market over the past few years is the so-called Desktop Mapping/GIS package. These have developed with the realization by vendors that not all users of spatial information are GIS experts; many people just want to carry out simple queries of spatial data sets.
As the name suggests, desktop packages are designed to run on desktop personal computers usually using a windows and mouse-based interface. These packages have fewer functions, and are primarily designed for simple analysis and the production of maps and graphs. A major limitation of desktop packages has been a difficulty in importing data. This is now being addressed by many traditional data suppliers and new value-added publishers. For a few hundred dollars, these packages are an excellent introduction to GIS.
The term "enterprise computing" has recently become popular, and is used to describe the situation where all the users of an organization or enterprise have access to a central information resource. In GIS terms, this might mean the vast majority of users using desktop GIS to query a central data set over a network. The central data base would be maintained and updated by specialists using high- end GIS toolkits. Top

1.What are the hardware requirements? Do these conform to the policy within your organization?
2.What data model(s) does the system use? Does it have the analytical tools required for your application?
3.Will you be able to use or convert your existing data? Does the GIS support the existing Database Management Systems in use?
4.How easy is it to input data? Can the system import digital data from your national mapping agency?
5.How easy is the system to customise? It is possible to design your own interface, and add features when requirements change?
6.What level of technical support is provided? Is there a dedicated technical support team? Does it guarantee response times? Remember: it is often difficult to deal with a technical support department in a different country.
7.Who are the existing users of the system? Can you talk to any similar organizations to your own who already use the software? Are there user groups?
8.How easily can the system be integrated to your existing Information Systems? Can it be networked? Does it produce standard format files that can be opened by your word processing, spreadsheet packages etc.?
9.What documentation is supplied? Is training available? How user friendly is the system? Is there context sensitive help available? Are there training courses? How expensive are they ?
10.Are there maintenance charges? (Unlike office automation software such as word processors, GIS - particularly high-end GIS - may be subject to a yearly maintenance charge, which covers support and upgrades which occur very frequently!!). Top

Parcel mapping for cottage properties of the Madawaska Club in Georgian Bay
Parcel mapping for our own internal survey records which consists of almost 50 years of surveys. Top