How to Use the General Purpose Viewer

The General Purpose Viewer (GPV) is a mapping web site that provides a consistent set of mapping functions across a variety of applications.  This document describes these mapping functions.  For specific information regarding the configuration, content and use of the GPV for a particular application, please contact the administrator of this web site.


Major Components of the General Purpose Viewer

The interface for the GPV is divided into several panels controlled by tabs. Depending on how your application has been configured, some of these panels may not be available.

Map Panel - A GPV application will always have a map panel. This contains the map itself and the basic controls needed to manage it.  At the top left of this panel are one or more map tabs. Clicking on a map tab will change the map to show different thematic layers.  If there are many tabs, you may see arrow buttons at the left and right ends of the tabs. Click and hold on either of these to slide the set of tabs to the left or right.  At the top right of this panel are three buttons that control the size of the interface.  Choose the size that best suits your screen size.  When the viewer is busy retrieving a new map or other data, an animated clock icon will appear temporarily toward the upper-left of the map.

Selection Panels - Some applications, but not this one, provide two panels that let you select features (mapped objects) on the map and retrieve information about them.  The top panel lets you choose one or two map layers from which you can select features and a filter for limiting the data shown.  It also has a grid for displaying the data.  The bottom panel has one or more tabs and shows detailed data for one of the objects highlighted on the map and in the grid.

Legend Panel - Some applications, but not this one, provide a panel which displays the legend for the current map.  Depending on its configuration, you may be able to expand and collapse parts of the legend.  You may also be able to click check boxes or radio buttons to turn thematic layers on and off. The changes to the layers do not appear immediately on the map when you click a check box -- you must click Refresh Map at the top of the legend to see those changes.  Clicking on a layer name that appears as a link should lead you to a page containing detailed information about that layer.

Location Panel - Some applications, but not this one, provide a panel with an overview map of your area of interest.  The red box shows the current location of the main map.  You can move and resize this box to change the extent of the main map.

Depending on the configuration of the application, you may also have additional tabs and links in the bottom panel which let you zoom to an area, set the map to a particular level, or do both operations simultaneously.

Markup Panel - Some applications, but not this one, provide a panel for creating and managing markups on the map.  You can draw groups of points, lines, polygons and text which are saved in a database and can be retrieved for viewing by others.

The Selection Panels, Legend Panel, Location Panel and Markup Panel occupy the same space on the interface.  When more than one are available in an application, you can use tabs at the top to switch between them.


Navigating Around the Map

Controls Available on the Map Panel

Zoom In/Out - Slide the vertical bar left or right to quickly zoom in or out on the center of the map.  You can click the minus button to zoom in one level and the plus button to zoom out one level. Every two divisions of the bar represent a zoom factor of two.

Scale 1" = [feet]' - Shows the current scale of the map.  You can enter a different scale here to zoom the map in and out.

Pan North/East/South/West - Click on one of the arrow buttons around the edge of the map to pan the map in that direction.

map

Full View - Zooms out to the full extent of the map.
Return to Previous Extent - Returns the map view to the last extent before the current one.  Every extent from the beginning of the mapping session is remembered, so you can click this repeatly to undo multiple pan/zoom operations.
Zoom In - When this is selected you can click on the main map, or on the overview map if the Location tab is available, to zoom in by a factor of two on that point.  You can also click, hold down, and drag a box on either map to specify a new extent for the main map.
Pan - When this is selected you can click and hold down on the main map to drag it in any direction.  If the overview map is available, you can use this tool to drag the red box to a new location, which will recenter the main map.

Getting Information

Identify - When this is selected, pointing at an object on the map will display a small box of information about that object.  Clicking on the object will popup a separate window with more detailed information. The popup will contain a link that lets you print the information.  Depending on how the GPV has been set up, it is possible that some objects on the map cannot be identified.
Display Coordinates - Displays the coordinates of the point you click on the map. These coordinates will continue to draw on the map until you click the Clear Selected Features button.
Measure Area - When this is selected you can click on the map multiple times to measure the area of a shape. The area will be shown inside the shape. Double-click to end the measurement.
Measure Distance - When this is selected you can click on the map multiple times to measure the accumulated length of a set of lines. The length will be shown where you first clicked. Double-click to end the measurement.

Help - Displays the help for the General Purpose Viewer in a pop-up window.

Communicating with Others

Printable Map - Pops up a utility for creating a PDF version of the current map suitable for printing or archiving.  You can select which page layout you prefer and specify whether you wish to preserve either the scale or the width of the current map.  Depending on the configuration, you may also be able to provide text, such as a title, that will appear at specific locations on the printable page.
Email This Page - Starts your email client with a message containing a link to your current map page. All the information about your page - the current map tab, zoom level, selected object, and markup - are encrypted in this link. You can add text to this message and mail it to anyone that also has access to this General Purpose Viewer. When they click on the link in the message, the General Purpose Viewer will appear exactly as you had set it.

Other Capabilities

Change the Size of the GPV - When you run the GPV for the first time, it will automatically set itself to one of three sizes depending on the resolution of your screen.  You can change the size of the GPV by clicking on one of the Size buttons.  The GPV will return to that size when you start it the next time.

   

External Map Viewers - The pulldown list to the lower left of the map lets you launch other web-based map viewers centered and zoomed to the same location as the current map.  Select the map viewer and click Go to pop it up in a new browser window.

Save Map - The pulldown list to the lower right of the map lets you save the current map image to a file. Select "as Image" to save the map as a PNG or JPEG image file. Select "as KML" to save the map in a format that can be viewed in Google Earth. Click Save Map to download and save the file.

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