Michael L. Binge
In the inaugural article for this column, my goal was to provide readers with a firm definition of Geographic Information Systems with some description and a brief history. Having established what a GIS is and what it does, we can move on to examine the GIS user community. So, exactly who makes up the GIS user base? And, what do they use a GIS for?

The Developers and Users of GIS

Nearly every large GIS is anchored and driven by a parcel level land basemap, an emergency vehicle routing system, or both. Academia is another large GIS developer.

It has been suggested that the E in ESRI (Redlands, Calif.) stands for Everyone. Though that may be something of an exaggeration, it is indeed contained in the title of its popular promotional publication, GIS For Everyone. However, users can be divided into three general categories: resource management, facility management and demographics.

Biology, geology and hydrology represent the environmental aspect of resource management. Community planners, land developers and their scientific consultant groups are the developers and principal users of this type of GIS data. Agronomics is another important member of this community. Transportation networks including all of their structural components, along with utility location, make up the largest part of the facility management group. Transportation planners, engineers, utility planners and facility maintenance managers work here. Surveyors typically work within both of these groups.

Demographic data contain population specific attributes, which normally contain no spatial elements themselves but are linked to map features through a process called geocoding. Demographics are usually compiled from census data, tax base data and market research. Demographics add fuel to the GIS business process. Health and human services providers and researchers, real estate marketing firms and financial lending institutions are major users of this type of data.

User Profiles

GIS users are most often grouped into three general levels of involvement.

1: The End User. The end user usually operates at the map browse level. This type of user can view data using either a standard browser, free downloadable viewer or a “plug-in.” He or she can make basic queries of the displayed data and generate simple reports. This level requires little or no GIS training.

2: The Professional User. This is the full “desktop” user level. It requires a GIS software package and training. The professional user can view, create, convert and analyze data, as well as create reports and hard copy maps. Some computer programming skills are also helpful at this level.

3: The GIS Analyst. This is the GIS professional level. It requires a robust GIS software package, high-end hardware to run it on and a network. The analyst must be able to support the other two levels of users. The analyst level requires advanced computer hardware, software and programming skills, in addition to some degree of expertise on the data contained in the system.

FAQs

Q. What is the role of the surveyor in GIS?

A. Surveyors fall into that group of users who are also providers of data. Along with this status come some additional responsibilities. The benefits of these responsibilities will far outweigh the burden in the long run. That is because it is important to keep in mind that a good analysis of bad data has the same net effect in a GIS that it does in surveying. The core layer of a GIS is almost always the parcel land base. And it is the surveyor who is responsible for the integrity of this land base data. (Incidentally, this is hardly a new concept. It dates back at least three centuries to the era of the “Enlightened Despots” who sought more efficient means to govern and tax their subjects.)

It is frequently stated that the greatest impediment to learning to use GIS applications is the inability to think spatially. Fortunately, surveyors by definition pass this litmus test by default. The greatest impediment to apply a GIS solution to a situation is the inability to think globally. And, unfortunately, far too many surveyors fall into this trap. Global is a keyword because GIS truly is a worldwide phenomenon. And today it is especially important to know and understand the relationship of our particular projects to the rest of the world. When this concept is fully grasped, the answer to the question of the surveyor’s role is whatever he or she wishes it to be.

Q. What skills are necessary to perform GIS work?

A. Good, solid computer skills are a basic necessity. Database construction, operation, design and maintenance are essential. Map construction and cartographic presentation abilities are of high importance. Data capture and data conversion capabilities are core functions in GIS construction. Surveyors usually enter the realm of GIS with a well-developed toolbox in the latter area.

Terminology Tip

GIS, like any computer intensive activity, has its own jargon. Out of necessity, I will use many of these terms in the context of writing about GIS. A complete GIS glossary is available for no charge online from the ESRI website at http://www.esri.com/library/glossary/glossary.html.

In the last column we explored ArcExplorer, the ESRI GIS data viewer at the end user level. Now we will take a look at ArcView. This ESRI desktop product has a full range of functions and available extensions to support the professional GIS user. ArcView version 3.2* currently retails for about $1,300.

The figure shown here is the standard “out of the box” ArcView graphical user interface, version 3.2. Starting from the top, the first row of controls is called the Menu Bar. It houses the Pull Down menus containing the names of the ArcView functions. The second row is called the Button Bar. It houses many of the same functions in the pull down menus. A button is basically a shortcut that employs an icon to identify the function to be executed. Allowing the cursor to pause over a button will cause a tool tip to appear displaying the name of the function. The third row houses the Tool Bar.

On the left side of the application window is the Project Window. ArcView files are called Projects and are saved with the extension “.apr.” ArcView loads “out of the box” with one “.apr” file: default.apr. It opens ArcView in the “default” interface. There are three “nevers” in ArcView:

1: Never name a project default.apr.

2: Never name a project default.apr.

3: Never name a project default.apr.

It is advisable to make a copy of the default.apr file and store it in a safe location. If the file is inadvertently overwritten, whatever is displayed when the project is saved becomes the default application window and graphical user interface (GUI).

There are five documents available to make up ArcView projects: Views, Tables, Charts, Layouts and Scripts. A project can contain any number of each. The View displays the map features. The Tables contain the attributes of the features displayed in the View. Charts are graphics constructed from tabular data. There are six types of Charts and they are very much like the charts displayed in Microsoft Excel and similar products. Layouts are ArcView print or plot files. Scripts by far are the most complex of the ArcView documents. They are basically user defined sub-routine programs. ArcView contains an internal, object-oriented programming language called Avenue. It allows the user to customize ArcView to suit his or her particular needs. With Avenue Scripts, the user can change the appearance of the GUI, automate repetitive tasks, create Extensions and develop applications.

The application window in the figure above displays a sample project showing a view, a table and a chart. An ArcView “layer” is called a Theme. Themes are made up of map features and their related attributes. The map features of themes are displayed in the view window. The view window has two sections, the Table of Contents (sometimes called the legend) and the map display. Themes can be composed of feature data (arcs, points and polygons) or image data.

The shapefile is the primary currency in ArcView. The types of files ArcView supports are essentially the same as those I enumerated for ArcExplorer. The astute reader may have noticed that the icons on the buttons and tools in ArcView are also the same or very similar to those on the ArcExplorer GUI. That could possibly raise the question, “Why should I buy ArcView if I can see the same data for free with ArcExplorer?” That’s a fair question.

ArcExplorer is a simple data viewer. The user cannot create or edit any data. ArcView provides the user all of that capability plus much more. There is a large variety of application extensions that allows users to handle a broad range of business and technical solutions. There are specialized CAD and image viewers, projection applications, spatial, 3D, imaging and routing analysts to name only a few. Several extensions are included with the standard package. Many more are available for free downloading. The more sophisticated are of the pay per ArcView extension variety. ArcView 3.2 also comes loaded with Crystal Reports, which work very much like the Reports function in Microsoft Access.

ESRI uses the concept of common tools within its products very well. That is very consistent with the basic Microsoft model. The prevailing theory at work here is, if the user is already familiar with a particular GUI configuration and associates a certain icon with a specific function, he can “port” his skills between applications. There is a perception in the software industry that this kind of standardization promotes user friendliness and flattens the overall learning curve.

Conclusion

In the next article we will take a look at that learning curve and discuss some GIS training and education issues. We will also look deeper into ArcView with a more survey specific eye. We will create a project, enter some data, edit data and take a tour of the Help menu.