Exploring the Information

In this, the final section of the tutorial, you will learn how to explore the map information by working with layers and examining the attributes of various map features.

Layer List

Hopefully you've had a chance to take a look at GIS Concepts where we discussed layers.

Because maps often have many layers, layers are organized into folders ( Folder ) and group layers ( Group Layer ) in the Layer List. (If you don't see the Layer List, click the tab in the Information Panel). When you first open a map, some folders and group layers may be open while others are closed. Similarly, some layers may be visible on the map while others are not.

To open a folder, click the folder icon. A list of the layers contained in the folder will display. To close the folder, click the icon again. To open and close a group layer, click the group layer icon. Notice that opening and closing folders and group layers doesn't change which layers are visible on the map; it simply helps you stay organized.

Showing and Hiding Layers

Beside every layer in the Layer List, you will see a check box. Folders and group layers also have a check box beside them. In order for a layer to be visible on the map, both check boxes must be selected: the layer's check box and the check box of its folder or group layer.

Folders and group layers work differently. When you select or clear a folder's check box, the check boxes of all its layers also become selected or cleared. Selecting and clearing a group layer's check box never changes the check boxes of its sublayers. When you select a group layer's check box, every sublayer whose check box is already selected becomes visible on the map, provided they're visible at the current scale. You can also change layer check boxes individually.

Figure 1. The Layer List

Making Layers Active

Some layers are only available at certain scales. Layers that are available at your current scale are shown with an Available icon ( Available Layer ) next to the layer name, while layers that are unavailable at the current scale are shown with an Unavailable icon ( Unavailable Layer ).

A layer can be made active by clicking its Available icon. An active layer is represented by an Active icon ( Active Layer ) and its name is highlighted in blue in the Layer List. Making a layer active is your way of telling the Geocortex software that you want to work with the layer. For example, when a layer is active, you can search for points of interest on the layer. You can have multiple layers active at one time.

Viewing Attributes of Features

As discussed in the Introduction to GIS, features have attributes associated with them in Geographic Information Systems. Suppose you are interested in the attributes associated with a particular street. To see the street's attribute information, click the Identify tool and then click the street on the map. (Depending on how your site is set up, you may have to make the street active first). Use the Identify tool whenever you want to examine the attributes of features on the map.

Viewing the Map Legend

In addition to the functions above, the Layer List can also display a Map Legend. To make the legend visible, click the View Legend button at the bottom of the Layer List. To hide the legend, click the Hide Legend button. Legend symbols are shown for available layers only. You can also open a legend in a separate panel using the Launch Legend Panel tool in the Navigation toolbar.

Figure 2. Activated Layer List Legend

Congratulations! You've finished the basic tutorial. Pretty painless, wasn't it?

While we've only scratched the surface of what can be done with web-based GIS during this basic tutorial, it is our hope that we've perhaps opened your eyes to the power of this technology.

Now, we encourage you to start working with Geocortex Essentials to put to use the information we've shared. While we've shown you the basics, we hope you'll spend some time reading the Tools and Tasks and Layer Actions sections, to learn how to use the tools and functions of Geocortex Essentials.

We'll tell you how you can draw on and add your own things to a map, create your own custom maps as PDF documents (which you can save and print), measure distances, search for and select features based on various criteria, and a whole lot more. We don't claim that all these tasks are dead simple, but we work hard to make everything as easy as possible.

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