USING ARCVIEW

IPM CRSP
VIRGINIA TECH - CARDI JAMAICA
INFORMATION SYSTEMS FOR COLLABORATIVE RESEARCH
GIS WORKSHOP
August 18 - 20, 1998

Larry Grossman

Department of Geography

Virginia Tech

NOTE: The materials on these pages--both in printed form and on the World Wide Web--are to be used only in association with the Virginia Tech IPM CRSP. Reproduction or use of these pages, in part or in full, for commercial purposes is strictly prohibited. Those wishing to reproduce or use these pages for non-profit, educational purposes should contact the author at LGROSSMN@VT.EDU for permission.

Acknowledgment: All coverages and part of the data in these GIS lessons are supplied by Glynis Ford of the Rural Physical Planning Division (RPPD), Ministry of Agriculture, Jamaica.

Step 6: Identify Features on a Map

Now we want to find out more about the themes displayed on a map. To do so (and for many other tasks related to analyzing a theme), you first have to make a theme active. To make it "active," click ONCE on the name of the theme in the Table of Contents (not in the check box to its left) and you will notice that the rectangular area around the theme's name appears raised.

Click in the boxes to uncheck all the themes except for Bpkcrops.shp in the Table of Contents so that only the map of Bpkcrops.shp remains. Click once on the name Bpkcrops.shp to make it active, as in the map below.

Now it is "active." Themes must be active to work with them (such as to open their attribute table, identify them, change their legend color or symbol, etc.). (NOTE: If something does not seem to be working when you try it, be sure to check that the theme is active; that is often the problem.)

To reveal the identity of an item on the map and the information associated with it that is stored in its attribute table (now hidden from view), click on the left-most icon in the second row of buttons at the top, the IDENTIFY tool, and then click on the feature on the map that you want to identify.

(Note: when you open a view in ArcView you are already in "identify" mode, which is indicated when the cursor appears as a cross-hairs with a small "i" to the right when placed over a map.)

After doing so, click on one of the areas in Bpkcrops.shp. A window will pop up with the heading Identify Results, providing the name and other attribute information about that area selected.

On the left-hand side of the "Identify Results" window is the name of the theme and the name of the feature being identified. On the right side is a table with two columns: in the left column, the "field" name is displayed and in the right column is the "value" (or result) for that "field." The term "field" is traditionally used when discussing databases and simply refers to a variable or attribute of a theme.

For example, the "value" for the "field" "Texture" is "clay."

(Note: when you see the value "-99" in a table, that means that Arcview has no data for that item.)

Usually, data on several "fields" will be present for a particular theme. In this case, the "fields" are "Texture," "Capability," "Usda class," etc.

If you repeat the process, that is, click on several areas to identify them, the name of each area identified will be listed on the left side of the window in the order in which they were selected.

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