ESRI: GSI and mapping software

Geography is a serious discipline with multibillion dollar implications for businesses and governments. Choosing sites, targeting market segments, planning distribution networks, responding to emergencies, or redrawing country boundaries—all of these problems involve questions of geography....the guide to GIS

The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. Most of the information we have about our world contains a location reference, placing that information at some point on the globe. ..How does a GIS work?

Even though most open-source software is freely distributed, your time is limited. So which software should you try first? That depends on what you want to accomplish, the kind of free software you want to deploy and the environment in which you work. How to choose GSI software

Geographic Information Systems

Definition: A Geographic Information System (GIS) is a collection of computer hardware, software and geographic data used to analyse and display geographically referenced information.

GIS Techniques

Modern GIS maps are created using Computer Aided Design (CAD) software to digitally render geographical maps, onto which can be superimposed any spatially located variables (i.e. rainfall, demographic data, etc.). GIS maps are used to create a visual representation of raw data (attributes) to allow for more efficient analysis and better decision making.

There are many GIS software applications available, ranging from open-source software such as GRASS to proprietary applications created by such organisations as AutoDesk and ESRI. There are also many specialist GIS applications developed for particular industries (such as General Electric’s Smallworld, developed for use in GIS mapping of public utilities).

History of GIS

GISWe have long used maps as a method of exploring the earth and locating natural resources. In fact, the origins of GIS are rooted as far back as 35,000 years ago, when early man drew cave paintings of the animals they hunted along with crude maps depicting migration trails. While the cave paintings only vaguely resemble today’s advanced geographic information systems they contain the same basic data as modern systems: geographic data linked with spatially dependent attribute information.

The more sophisticated modern GIS can be tracked to John Snow’s 1854 map of the distribution of incidences of cholera in 19th century London. While it is only a fairly basic 2-dimensional rendering, Snow’s map is a useful tool to demonstrate the data analysis possibilities of GIS. When viewed in isolation, a list of cholera cases suggests nothing as to the origin of the outbreak. When that same data is translated into a GIS map the data takes on new meaning, allowing the analyst to track down the outbreak to an infected water pump in the centre of a cluster, giving the authorities the opportunity to curtail the outbreak and save lives.

Applications of GIS

Quite simply, GIS provides a method by which geographically dependent data can be displayed in an easily understandable visual format to simplify the process of decision making. The possible applications of such a tool would stretch to several volumes, but here are a few examples of the possible uses:

* Earthquake Mapping

GIS is often used to map tectonic activity in earthquake prone regions for purposes of both public safety and commercial interests.

Commercially, tectonic activity would be of great interest for the decision making process of insurance companies in setting earthquake insurance premiums. Clearly, premiums will be much higher in tectonically active areas such as the West Coast of the United States than in relatively stable regions such as the Mid-West. To enable insurance brokers to determine premiums it is necessary to utilise GIS software in mapping past tectonic activity in order to make a ‘best guess’ about future earthquake events.

Tectonic mapping through GIS is also used as a public safety measure by the United States Geological Survey (USGS). These GIS maps are essential for creating and updating building codes. They can also be extremely useful for the purposes of studying past earthquake events in order to improve and perfect prediction techniques with a view to creating an early warning system which would predict earthquakes and allow emergency response organisations such as FEMA to react more quickly to natural disasters.

* Market Research

Geographic Information SystemsRather less urgent - but no less important to industry - is the fact that GIS can be used to make decisions regarding the provision of products and services. For instance, enterprises can use GIS to analyse demographic data in an effort to locate the regions in which their products can be expected to succeed (high-income regions for luxury items, for example). This sort of analysis can be extremely useful in apportioning a limited advertising budget, allowing the funds to be effectively channelled towards regions densely populated by the target demographic.

* Demographics, Health Research and Census Data

The range of data collected by governments about their citizens can be truly enormous. In their raw form these data are largely useless to all but the most committed of researchers. When translated into an easily understandable visual format by GIS software, however, census data can be of great use in the shaping of public policy. Data regarding such subjects as health and education levels can be used to better apportion government spending in these areas, leading (ideally) to more efficient use of government funds, increased life expectancy, the creation of jobs and an upturn in economic growth, along with a whole host of subsidiary social benefits. Additionally, GIS can aid health workers in such fields as cancer research.

Free GIS software

There are several open source and other GSI software and GSI tools available.

There is this category in gsiwiki. There's also

- The Free GIS Project
- Geomatica, scripts, tools, extensions and more
- MapWindow (open source)
- Tatuk GIS viewer
- ArcExplorer GIS data viewer. (Also: ArcReader & MapExplorer)
- MapMaker Gratis
- Brava Reader
- ERDAS Viewfinder
- JTMaps

and other collections (1) (2) (3) (4) of free applications.