PDT Web Map Client

Bringing detail-in-context viewing & data manipulation to online data sets

The PDT Web Map Client was developed by IDELIX in conjunction with GeoConnections and implements OpenGIS® WMS specification. The PDT Web Map Client is powered by Pliable Display Technology (PDT) and demonstrates the access of geospatial data over the Internet while providing PDT's detail-in-context viewing capabilities.

Unique to the PDT Web Map Client is the ability to view different layer combinations inside the lens region from the base map appearing outside the lens region. This enables faster and easier comprehension of high-density data sets as you can focus your eye to areas of interest and avoid the feeling of data claustrophobia.

This demo will also demonstrate how integrated PDT lenses can support a variety of host application tools to improve accuracy and efficiency of tasks such as distance measurement.
 

PDT Web Map Client Quick Start Instructions

Below is a brief description on how to interact with the PDT Web Map Client Demo.

The PDT Web Map Client is one of the most robust demos that IDELIX has produced for public distribution to date. We strongly urge you to read the complete Help Manual for more detailed instructions and to explore the full capabilities of this demo. To preview the Help Manual, simply click on the Help button located within the Menu bar of the demo and select Help Topics from the drop down menu.

You can also download a PDF version of the full instructions.
 

The PDT Web Map Client Window

 

  Load an Image Example

Six example data sets have been selected and bookmarked for quick preview:

To load any of these pre-selected examples simply select the name from the Examples drop-down menu located in the toolbar. These examples will connect to a server, set up the layers and styles, retrieve a map from the IDELIX map server, and add a PDT lens for immediate user interaction.

Through the Map drop-down menu on the toolbar, you can also access map data from some pre-selected web map servers that implement OpenGIS® WMS specification. Click on Servers, then select the web map server you would like to connect to. Once a connection is made, a list of the possible layers you can use to create a map is retrieved. Check the layers you wish to view, then click on the Request map button. The sever will create a map based on the selected layers and return the appropriate map.
 

  Request Map after Adjusting Data Layers

The data appearing within both the base map and the PDT lens are layer combinations that have been pre-selected by IDELIX. Additional data can be selected or unselected by double clicking on the boxes located in the Base map layers and Lens layers menu tabs located to the left of the PDT Web Map Window. After you have selected your data preview for both the Base map and Lens, click on the highlighted Request map button to update the data set to your selected viewing preferences.
 

  Apply a PDT Lens

There are three PDT lens shapes to choose from: The PDT Pyramid lens, the Cone lens, and the Circle-Square lens. To add a PDT lens, left-click on the button that corresponds to the chosen viewing shape. The lens shape that appears within the PDT Web Map Client Window can be easily changed by selecting the desired lens button located in the toolbar.
 

  Activate & Manipulate the Lens

Once the base and lens data layers have been adjusted, click on the arrow Lens mode button in the toolbar to indicate you are ready to move and re-size the lens and inspect the map view information. Left-click and drag with your mouse anywhere within the lens to move the lens.

Redrawing Note: When the lens is first moved to a new location, the magnified section of the map needs to be redrawn. To reduce the amount of time spent waiting for a single map request, the PDT Web Map Client requests higher resolution or magnified portions of the map in tiles depending on where the PDT lens is located on the map.
 

  Adjust Lens Size, Shoulder, and Magnification

Control the PDT lens with the in-place Modular Design Lens Control (MDLC) handles and sliders. The lens magnification, position (click and drag), and size can be manipulated with the MDLC user interface. The focal region and base sizes can also be changed by clicking and holding the left mouse button down and dragging the respective handles that surround the focal and base regions.
 

  Fold and Unfold the Lens

Once the cursor changes to the folding icon, click and hold the left mouse button down and drag on the focal region boundary to move the focal region with respect to the lens base. The resultant displacement of the focal region is called Folding. Click on the Unfold button in the toolbar to remove all lens folding.

Folding the PDT lens allows you to inspect areas of interest in the shoulder of the lens without repositioning the lens. If data is not clearly visible in the lens shoulder, folding the lens will extend the shoulder region and make the data easier to view.
 

  Select the Viewing Scale

Once the PDT lens has been placed on an area of interest, left-click on the Zoom to lens scale button to center your area of interest into the middle of the PDT Web Map Client Window and to set the overall viewing scale to that which appears within the focal region of the PDT lens. To reactivate a lens, select the appropriate lens shape from the toolbar.
 

  Measure Distance with the Lens

Measure functionality was added to the PDT Web Map Client to demonstrate how PDT supports a variety of host application tools to improve accuracy and efficiency of tasks such as distance measurement.

Activate the Measure Tool with the PDT Lens:
This will enable the view of the start and end points to be magnified at a higher resolution in the lens for more accurate calculations.

To combine the Measure tool with the PDT lens, you will first need to activate a lens within the PDT Web Map Client Window, to retrieve the higher resolution tiles and to display your starting point at a higher, more accurate resolution (see Redrawing Note above). Once the lens is positioned, left-click on the Measure tool in the toolbar. This will place you in measurement mode.

To attach the Measure tool cursor to the PDT lens, click the left mouse button on the start point appearing within the lens or lens shoulder. To have the lens follow the Measure tool, hold the right mouse button down while you drag the lens and measurement line to the stop point. Once the cursor is positioned over the stop point, left click once to plant a point and continue, or double-click the left mouse to detach the measurement line from the cursor, and select another functionality from the toolbar.

Release the Lens:
Click the right mouse again to release the PDT lens.

Activate the Measure Tool without the PDT Lens:
The Measure tool will be most useful if you retrieve the higher resolution/magnified tiles from the map server (see Redrawing Note above). The PDT lens will need to be activated in order to do this.

After you have retrieved the higher resolution tiles, left-click on the Measure tool located within the toolbar. Place your cursor over where you would like to establish the start point, left-click and drag the cursor to your selected stop point on your picture. A distance measurement line should appear between the start and stop points. Once the cursor is positioned over the stop point, left click once to lay down a point and continue, or double-click the left mouse to detach the measurement line from the cursor.
 

  Remove the Lens

To delete a lens and view data in an undistorted state, simply left-click on the Remove lens button located in the toolbar next to the lens shape buttons. A lens can be re-added by clicking on the desired lens shape button.
 

  Print the PDT Web Map Client Window

By selecting the print option, you can print the view of the data set that appears within the PDT Web Map Client Window. If there is a PDT lens visible, or distant measurement lines drawn on the data appearing within the window, these will also appear on the print out.
 

  Pan the Image

Use the Pan button to click and drag the map in any direction. Left-click on the Pan button located in the toolbar. Once this tool is selected, the cursor will change to a hand. Hold the left mouse button down and drag the data in any direction to suit your viewing needs. To re-activate a PDT lens, simply click on one of the lens shapes found in the toolbar.
 

  Zoom In and Out

Use the Zoom in and Zoom out buttons to select your view. Select the appropriate tool by left-clicking on the button in the toolbar. Once one of these tools is selected, the cursor will change to a cross-hair. Hold the left mouse button down and draw a rectangle around the region that you wish to zoom into or out of. To re-activate a PDT lens, simply click on one of the lens shapes found in the toolbar.
 

  Feature Information

If additional information is available for the map appearing within the window, the Feature info tool is used to query the data and display all the information available in a separate window.
 

  Go Back and Forth Between Maps

Use the Back and Forward options to view previously requested maps. If the map or zoom you requested is not suitable, left-click on the Back button to go back to the map view prior to zooming. Left-click on the Forward button to recover your previous view.

For a full technical description of PDT functionality, see our Technical Description.