US: The US Department of Agriculture”s (USDA) National Agricultural Statistics Service (NASS) has launched a new state-of-the-art, satellite-based US crop condition vegetation assessment and monitoring service named VegScape. Like the popular CropScape geospatial product, VegScape delivers interactive vegetation indices so that web users can explore, visualise, query, and disseminate current vegetative cover maps and data without the need for specialised expertise, software, or high end computers.
The agricultural community, policy makers, researchers and other interested parties now have a tool for policy decisions, scientific inquiry, and educational efforts. New satellite-based data are loaded on a weekly basis during the growing season. One can compare year-to-year change for 12 years, compare conditions at a given time to mean, median and ratio vegetative cover over the 12 year span, and can overlay a crop mask to help identify crop land versus non-crop land, among many functions. When viewing the maps in most cases the deeper the green colour the stronger the plant vigour while yellow/brown indicates poorer conditions.
Vegetation indices, such as the NDVI (Normalized Difference Vegetation Index), and mean, median, and ratio comparisons to prior years have proven useful for assessing crop condition and identifying the land area impacted by floods, drought, major weather anomalies, and vulnerabilities of early/late season crops. Additionally, the National Aeronautics Space Administration’s MODIS satellite that NASS uses for this project provides imaging at 250 meter (15 acres) per pixel resolution and 12 years of data history. The high quality spatial information and daily satellite overpasses deliver detailed timely crop specific condition information. Additionally, the data can be directly exported to Google Earth for mashups or delivered to other applications via web services.
In addition to the new VegScape product, NASS released the 2012 Cropland Data Layer (CDL) on January 31, 2013 via NASS’ CropScape geospatial portal https://nassgeodata.gmu.edu/CropScape. The newly released 2012 CDL product depicts agricultural land cover over the continental United States at 30 meters resolution.