Current data year displayed
Adjust data transparency
Application guide
Site credits and references
View data legend
These buttons drop menus that allow overlay selection and provide options for viewing data
Click anywhere to exit
About

This is a land cover change visualization and data download tool. Visualize change by making selections from the menu panel on the left. The following instructions serve as a brief guide to its operation.

Recommended Browsers

In order: Chrome, Opera, Firefox

Select layers

Base layers

Pressing the "Select Base Layer" button on the menu panel reveals a set of map base layers that provide context, including place names, roads, topography, and aerial imagery. One layer is visible at time and selected by activating the radio button corresponding to the desired layer. These layers are made visible by reducing the opacity of the overlying data layer using the vertical slider position at the upper left corner of the map.

Data layers

Pressing the "Select Data Layer" button on the menu panel reveals a set of map data layers describing attributes of land cover. One layer is visible at time and selected by activating the radio button corresponding to the desired layer. The opacity of these layers can be reduced to show underlying base layers using the vertical slider position at the upper left corner of the map. A question mark icon to the right of each layer can be clicked to load a page with metadata.

Download Tile

Pressing the "Select Download Tile" button on the menu panel reveals a set of vector overlays to help with selecting regions for download. Double click in the map display to select a tile for download, and click once on a selected tile to remove that tile from your download list. Once a tile is selected the region will become opacity, and the download button under "Select Download Tile" will display the number of tiles selected. Pressing the download button will open a download form where all that is needed is an email address and your choice of datatype(s). Note that while the feature callout option is active, time series plotting by left mouse click is disabled.

Map Interaction

Zoom

You can zoom in and out by using the mouse wheel or zoom to a box size by pressing the shift key then clicking and dragging on the map.

Pan

You can pan around the map by holding left mouse click and dragging.

Time Series

You can view a time series plot of the data displayed on the map by left clicking on a location of interest. The time series is an annual interval. Hovering on a time series line will display data value and year at each observation. Note that while the feature callout option is active (described above), time series plotting is disabled. The first time that you plot a time series, you might be waking up the drives, which will delay drawing the plot, subsequent requests for plotting will be near-immediate.

Viewing options

The default data view is the most current year of data for biomass. At any time you can display the data legend by clicking on the legend icon at the bottom of the button group along the upper left side of the map - the legend toggles on and off with a left mouse click on the legend button. Time series plotting with left mouse click works with all views.

View Single Year

Pressing the "View Single Year" button activates a single map view of selected data (the default view). A horizontal slider allows you to change the data year displayed.

Compare Years | Flicker

Pressing the "Compare Years | Flicker" button activates a single map view of selected data that will flicker between two years of data for easy identification of change. Two horizontal sliders allows you to change the data years displayed. Press the "Start Flicker" button to begin flickering the data years, press it again to stop. At any you can change either year slider, which will automatically stop the flickering. You can also change data layer opacity as well as base and data type at any time - flickering will not stop. Change the flicker speed using the "Flicker Speed" slider - units are milliseconds.

Compare Years | Split

Pressing the "Compare Years | Split" button activates a side-by-side map view of selected data that shows the top slider year data on the left and the bottom slider year data on the right. The map zoom and pan are synced, as is the cursor - the main cursor is an arrow while the synced cursor is a red circle.

Compare Years | Swipe

Pressing the "Compare Years | Swipe" button activates a side-by-side map view of selected data that shows the top slider year data on the left and the bottom slider year data on the right. Left click and drag the map swipe handle side-to-side to alter the year overlays.

Credits

Select Layers

Select Base Layer

Select Data Layer

Select Download Tile

Select Tile(s)
Viewing Options

View Single Year

Compare Years | Flicker

Flicker Speed (ms): 300

Start Flicker

Compare Years | Split

Compare Years | Swipe

Data Download Form

Data is available as tiles defined by the USGS ARD grid. A list of these grid tiles can be seen under "Region Selected". Please select the desired datatype(s) and enter your email address to receive data. Requested data can be accessed through download links emailed to you shortly after submitting the request. Data will be available for one week.

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Select data

Region Selected