Long Term Agroecosystem Research Data

System maintenance in progress. GIS map is not currently available. Other data and links are available.

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Content on this website will not be current or maintained until funding issues have been resolved.

Long-Term Agroecosystem Research Data Overview

The USDA Agricultural Research Service (ARS) Long-Term Agroecosystem Research (LTAR) network consists of 18 Federal and university agricultural research sites with an average of over 50 years of history. LTAR was established to build the knowledge required for sustainable intensification of agriculture, increasing yields from the current agricultural land base while minimizing or reversing agriculture’s adverse environmental impacts.

Map
Detailed Information
Image Overlap
Image Years

Display Options

Choose the information layer you want to view. This section can be displayed/hidden by using the icon showing selection tree with check marks.

tool in the main toolbar. Click on the box before the name to display/hide the information. The symbol on the map is shown to the right of the box before the name. Layers with multiple symbols show an document icon indicating the values will be shown in a pop up legend.

LTAR

Click on the LTAR sites to display information about that location.
The Display Options (left side) has an expandable list of other information that can be displayed on the interactive map. Click on a + box to expand that section, on the – box to collapse it.
Data from LTAR sites available in several existing data networks are the remaining choices in this section of the Display Options.
Aerial imagery is available for several locations. The Display Options provides the imagery years at those locations. You can zoom in on the location to see the imagery or click on the LTAR site or click it and see the Aerial Imagery section in the Detail tab.

Other Research Networks

Other national ecosystem research networks are available on the map to show how LTAR contributes to nation-wide coverage.

Boundaries

Administrative and statistical boundaries. You may need to zoom in to clearly see boundaries for smaller areas such as Agricultural Statistical Districts.

Ecological Context

Various characteristics relevant to agricultural production.

Base Maps

Shaded relief base maps are recommended for general data browsing since color imagery base maps can make other layer symbols difficult to see.
USGS digital topographic maps were created at 1:24,000 scale. If you zoom in too far, they will not be visible since their resolution is limited.

Display Options

Click to show or hide Display Options section on the left that contains a list of the data that can be displayed.

Map Legend

Click this button to show/hide pop up layer legend that displays symbols for layers with more than one symbol.

NRCS Land Resources, Seasonal Drought Outlook, Land Surface Forms, Surface Lithology and Topographgic Position have such legends.

Show Point Information

Click this button to turn on this feature. Then click on the map to display information about the clicked location.

At this time only the NRCS Web Soil Survey Data layer provides information.

Compare layers

Choose a layer from dropdown list and use the swiper to reveal what is beneath the chosen layer

Measure Distance/Area

Click on beginning point and move mouse to next point. As the mouse moves the distance (or area) will be displayed. To change direction, click on the turning point and continue to click along the path for distance or to finish drawing the polygon corners for area.
Draw a polygon shape on the map to measure areas

Save map as PNG image file

Click this button to download current map

Zoom Controls

Start with clicking this buttion, and then draw a rectangle on map canvas as target area to zoom in
These two buttons allow you to go back and forth between two map extents.
Often used to 'undo' accidentally zooming to the wrong extent.
Click to view map in full screen. Click again or use ESC key to return to normal view.
Click to zoom to Continental United States

This feature lets you compare aerial imagery from different dates.

How to select images or GIS layers to compare

Select different images/layers from the two dropdown lists at the top of the window. The one chosen on the left will be shown with blue borders. The one on the right with a red border.

Swiper and Spy View Tools

Swiper and Spy View are two ways to compare parts of the two images from different years.

The Swiper tool has a movable vertical line dividing the display of the image on the left and right. The left and right images are selected in the left and right lists at the corresponding top corners.
The Spy View displays the the image from the left list on the full map. A movable square viewer shows the corresponding portion of the image/source from the right.

Compare using "Swiper"

Move the slider (dot or bar) in the grey bar at the bottom of the map frame to shift the dividing line across the area of interest. The red and blue progress lines show where the swiper is. The black dividing line shows where comparison is about to happen as you move the sliding bar.

Compare using the "Spy View"

The left (blue) image is displayed. Move the mouse (or your finger) over the image and a red square will replace the image within the square with the right (red) layer. To to change the size of the square, use the up and down button on your keyboard.

What do the red and blue colors represent?

To make it easier to tell what part of the display shows the layers selected on the left and right, the list border, image boundaries, spy view, and swiper progress lines are all color coded. Left is always blue, and right is always red.

System maintenance in progress. GIS map is not currently available. Other data and links are available.

Long-Term Agroecosystem Research Data Overview

Image Overlap Explorer