The Distribution Viewer (DV) is a powerful application for viewing species distributions across the globe. By utlizing a combination of Goolge Maps, JavaScript, and Perl, the DV performs real-time database queries and displays the results in your web browser.

Users can:

• query species distributions with specific geographic filters
• save and share links to these distributions with others
• view the maximum range of a species
• view worldwide species distributions
• download data in multiple formats such as KML (for viewing with Google Earth) or CSV (for use with popular GIS applications such as ESRI's ArcGIS)
• toggle political and satellite backgrounds with a mouse click

The following buttons will help you navigate the distribution viewer's map interface.

In order to increase map performance, points and clusters are buffered outside of the current map view by half of its height and width. This allows you to pan the map without forcing a map refresh. However, once the map is panned beyond this buffer or is zoomed to a new level, the map will be greyed-out and the current view will be requeried.

One limitation of Google Maps is the number of points it is able to display (in the low hundreds) before it begins generate JavaScript errors. Since many species have distributions comprised of thousands of records, the DV would come to a screeching halt if it were to attempt to map all of these records. However, through creative programming, the DV has the ability to cluster points together. The results are displayed as a semi-transparent red squares instead of individual dots.

Each time the map is zoomed or panned, the map is greyed-out, and the DV requeries the database to determine the total number of records in the current view. Clustering only occurs when the total number of records in the current, buffered view is above a certain programmatic threshold. If the number of records returned is below this threshold, only regular points are displayed.

Users can filter their search criteria by both species and location.

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After results are displayed on the map, click one of the links on the upper right-hand side of the DV to download all data in the current view as KML (used by Google Maps) or CSV (a text file format).

 

Even though clusters may be displayed in the DV, all records will be downloaded as point data.

 

Hint: If you want to download a species' global distribution, click on the Zoom to Maximum Map Extent button, then download the data.

The DV can geocode addresses, cities, or other locations recognized by Google Maps.

By typing in a location and then clicking the "Search for Address" link, the DV will display a small, red marker on the map. Clicking on this marker will display the location, latitude, and longitude in a popup bubble.

You may search for multiple addresses multiple times, however, once the map is requeried, only the last entered location will be marked on the map. Until changed, this marker will persist throughout all subsequent searches.

Mac OSX

To capture the entire screen:

• Press Command-Shift-3.

To capture a portion of the screen:

• Press Command-Shift-4, then click and drag the cursor to mark the area you want to capture. When you lift your finger from the mouse button, Mac OS X will record that real estate and place a .pdf file on your desktop.

Windows

To capture the entire screen:

• Press the PRINT SCREEN key. The image will be copied to the clipboard.
• Open an application such as Microsoft Word and press Ctrl-V to paste.

To capture the current window:

• Make the current web browser window active by clicking on it.
• Press ALT + PRINT SCREEN. A screen shot of the window will be copied to your clipboard.
• Open an application such as Microsoft Word and press Ctrl-V to paste.

To make a bookmark or share a distribution you've created, the DV provides a link to the current view. Use the hyperlink "Link to this distribution" in the upper right-hand portion of the DV.

To help maps load more quickly, the distribution viewer buffers points around the initial view. As a tradeoff, these results are not displayed in the results frame.

To update the results, just click the "Show Distribution" button.