ArcView II Tutorial Instructions

In this exercise you will learn to use the ArcView GeoProcessing Wizard. This is an extension in ArcView which must be "turned on" in order for it to be available to you. To do this, select File-Extensions from the project window, scroll down and select GeoProcessing, then click ok. You should now see GeoProcessing Wizard under the View menu.

GeoProcessing is a way to create new data based on themes in your view. In most cases you will alter the geometric properties of the features in a dataset while controlling some aspects of how its attribute data is handled.

To reduce the extent of a theme

This process creates a new theme by using a polygon theme (or selected polygons in that theme) as a cookie cutter on a point, line, or polygon theme. The output theme will only contain data from the theme you're clipping--the theme used as a cookie cutter is only used to define the clipping boundary. You might use the boundary of your study area to clip a theme of roads or customers that extends over a much larger area.

This process is similar to clipping a theme, except it preserves only those features falling within the spatial extent common to both themes. The features of the input theme are intersected or sliced by the intersect theme. The attribute data from both themes are included in the new theme's attribute table. You could use of theme of flood zones to intersect a theme of land parcels.

To combine features in one theme that are alike

Dissolving features in a theme coalesces adjacent features that have the same attribute value. You might dissolve a theme of U.S. census counties based on predominant political affiliation. This would remove boundaries between adjacent tracts with the same predominant political affiliation.

Union creates a new theme by combining two polygon themes. The new theme has data and shapes from both themes, including their intersection. In fact, union differs from intersect only by the fact that all the features of both themes are included in the resultant theme, including those features that did not overlap.

Using merge is similar to union--a new theme is created from multiple themes but their features are not intersected. Merge allows you to combine the features from two or more themes of the same geometric type. When you merge themes, you specify which theme has the same fields you want the new theme to have. If the other themes you're merging have more fields than the theme you have specified, those fields won't be in the new theme's table. If the other themes don't have the same fields as the theme you've specified, empty cells will be added to the new theme's table. You might merge several tiled county themes with census data to make a metropolitan area.

Assigning data by location uses a spatial relationship to join data from one theme to another theme. For example, a travel agency concerned about client safety might assign data from a theme of hotels in a major city to a theme of crime events. The hotel data would be added to the crime event data, along with the distance to the hotel nearest the crime event. As a result the hotels nearest the most crimes may not be recommended to the travel agency’s safety conscious clientele.

As mentioned above, the ESRI data needed for this assignment has already been loaded and is available under "C:\esri\esridata." But you will also need a data set that can be downloaded from the data access pages of the World Wildlife Fund. In an effort to aid the preservation of biodiversity, the World Wildlife Fund has produced a map of ecoregions of the Earth. 

What are ecoregions?

Over the past eight years we have developed a biogeographic regionalization of the Earth's terrestrial biodiversity. We term our biogeographic units ecoregions, which we define as a relatively large unit of land or water that contains a distinct assemblage of natural communities sharing a large majority of species, dynamics, and environmental conditions. Ecoregions represent the original distribution of distinct assemblages of species and communities.

This ecoregion map has multiple uses for efforts to conserve biodiversity around the world. It provides:

You can read more about the creation of this map and its many uses in a paper published in BioScience in 2001 (click here for a full-text PDF file).

You will need to download and unzip this landcover map to use it in ArcView.  Proceed to the WWF terrestrial ecoregions page and select "Download the terrestrial ecoregions database" at the bottom of the page.  You will need to enter your name, email address, and organization and then it will allow you to download the file. Save it to your student directory and unzip it. You should see 5 files, one of which (the .shp file) will be very large. You should now be able to add this coverage as a theme in an ArcView View window.

1.) Produce a landcover map of the World Wildlife Fund ecoregions for the continental United States.

Open ArcView

Open a new View

Add the WWF Ecoregions theme to your view. Notice that this is a world coverage.

Add the US States theme to your view, found in the ESRI data folder.

Select File-Extensions and turn the GeoProcessing Wizard on.

Use the GeoProcessing Wizard (found under the View menu) to create a new ecoregion landcover theme for the continental United States.

Place that new theme into your view.

2.) Create a Layout (View-Layout) for this new theme.

Give it a meaningful title

Use the Text Tool to place your name on the layout

Include a scale bar and a north arrow

Include a legend with all landcover categories included

Save a digital version of this map and turn it in with your assignment.

3.) Create a new theme from the US Ecoregions theme including only Kansas.

Create a layout for this theme (as before) and save a digital copy of it.

4.) Add the US Cities theme to your view.

What is the name of the landcover category in which Emporia is located? (Be sure to zoom in close enough to distinguish the categories.)

5.) Create a new theme that includes all of the US Cities found within your Kansas Ecoregions theme. Select these cities from the US Cities Table instead of the view. Can you query the table or manipulate the table in such a way as to speed up the process of finding all of the cities in Kansas?

How many cities are in your new theme?

How many cities in your new theme have populations in 1990 > 15,000?

6.) The techniques you have used to complete this assignment barely begin to scratch the surface of what GIS technology and ArcView can do. However, even with this brief introduction you should have some idea of how useful such procedures can be. With this in mind, discuss several ways in which you think this technology may be useful in your own field of expertise. (Hint: think about other data you could have used in the above assignment besides cities, states, etc.)