USDA Crop Explorer: Global Crop Condition and Commodity Production Analysis from the USDA/Production Estimates and Crop Assessment Division (PECAD)Entry ID: USDA0557
Abstract: The Production Estimates and Crop Assessment Division (PECAD) of USDA's Foreign
Agricultural Service (FAS) is responsible for global crop condition assessments
and estimates of area, yield, and production for grains, oilseeds, and cotton.
The primary mission of PECAD is to produce the most objective and accurate
assessment of the global agricultural production outlook and ... the conditions
affecting food security in the world. Regional analysts use a Geographic
Information System (GIS) to collect market intelligence, and forecast reliable
global production numbers for grains, oil seeds and cotton.
The FAS has a global network of attach's that provide on-the-ground reports of
observed crop and contextual information. Also, the FAS regional analysts
travel extensively in the countries they cover to more fully develop the
context and constraints within which their assessments are made. Other
contextual information such as official governmental reports, trade and news
sources play a significant role in interpreting how these factors will affect
price and policies and other econometric analyses. PECAD's final production
estimate, produced by the 10th day of each month and cleared by the World
Agricultural Outlook Board, is based on an all source convergence of evidence
methodology. The final production estimates are used in a variety of ways:
- Official USDA statistics
- Principle Federal Economic Indicators
- Crop conditions and early warning alerts
- Agricultural monitoring and food security
- Foreign aid assessments for food import needs
- Disaster monitoring and relief efforts related to food aid
- Commercial market trends and analysis
- Trade policy and exporter assistance
PECAD relies on remote sensing data from satellite sensors (Figure 2) as an
important source of data for its GIS. Selected data sets provide daily,
weekly, and targeted coverage with resolutions ranging from 1km to less than
1m. The data is stored on a terabyte server accessible to each analyst
workstation. The most common data formats used operationally with ArcGIS at
PECAD are TIFF and compressed MrSID images.
The Crop Condition Data Retrieval and Evaluation database (CADRE) is the main
decision support tool used in the GIS by PECAD analysts. CADRE is a global
grid-based, geospatial database that stores daily, monthly, and decadal
(10-day) data. The sources for this data are the Air Force Weather Agency
(AFWA) and the World Meteorological Organization (WMO). PECAD takes this
source data and models precipitation, temperature, soil moisture and crop
stages. To measure vegetative vigor, PECAD calculates vegetation index numbers
(VINs) from satellite derived data. The data is imported into 1/8 degree mesh
grid cells (Figure 3) and can be categorized by:
Time-series data sets:
- Daily WMO station data (precipitation, min and max temperatures)
- Daily agrometeorological data derived from station and
satellite data include precipitation; min and max temperatures; snow depth;
solar and longwave radiation; potential and actual evapo-transpiration.
- Biweekly and decadal vegetation index (VINs) derived from Local Area Coverage
(LAC), approx 1.1-km pixels and Global Area Coverage (GAC), approx 8-km pixels
from the NOAA-AVHRR satellite series.
Normal baseline data sets:
- Normal precipitation and temperature values for WMO stations (from WMO and
- Normal precipitation, temperature, potential evaporation, and elevation
imported into1/8 mesh grid cells from UNEP/GRID-Geneve
- Soil-water holding capacity based upon the United Nations Food and
Agriculture Organization's (FAO) Digital Soil Map of the World at 1:5M scale
- Biweekly VIN normals or averages for the GAC data set.
Crop Information and Models:
- Crop type and average start of season
- Average yield and area planted
- Percent crop production within a country
- Two-layer soil moisture algorithm
- Crop calendars (based on growing-degree days)
- Crop stress or alarm models for corn and wheat (based on soil moisture and
- Crop water production functions to estimate relative
yield reductions (yield reduction models)
- Crop stage models by Ritchie
CADRE extraction routines:
- Automated maps and graphs generated every 10 days for diaplay
- Interactive ARCVIEW 3.2 scripts for displaying station and grid cell data
- Interactive CADRE X-tract program for displaying graphs
The Crop Explorer web application features near-real-time global crop condition
information based on the satellite imagery and weather data processed by PECAD.
The web mapping application uses Cold Fusion, Java, ArcIMS, SQL Server, and
ArcSDE to manage and store the geospatial data. ArcSDE relationships are set
up between PECAD "regions" and the various feature classes used by the maps
(e.g. rivers, administrative boundaries, etc.). The Crop Explorer ArcIMS
MapService is built using these same ArcSDE features. During a map generation
request, the grid-cell layer feature class is joined to the appropriate
attribute data such as precipitation, soil moisture, or temperature. Java is
used to build the necessary AXL code to make the request to ArcIMS. Cold Fusion
manages the map display in the web browser.
Thematic maps of major crop growing regions depict vegetative vigor,
precipitation, temperature, and soil moisture. Time-series charts depict
growing season data for specific agro-meteorological zones. Regional crop
calendars and crop area maps are also available for selected regions. U.S.
producers, traders, researchers, and the public can use Crop Explorer to
visualize this information with a web browser.
Regional droughts or excessively wet conditions can be easily identified by the
amount of ground-surface "greenness" as depicted by the Normalized Difference
Vegetation Index (NDVI), a measure of vegetative vigor derived from AVHRR
satellite imagery. In addition, daily satellite image composites originating
from the NASA MODIS Rapid Response System are now directly linked to selected
agricultural regions within Crop Explorer.
Data Center: Foreign Agricultural Service (FAS)
Dissemination Media: Online
Web Mapping and Metadata: http://www.pecad.fas.usda.gov/cropexplorer
Country Reports: http://www.pecad.fas.usda.gov/
Data Set Citation
Dataset Originator/Creator: USDA FAS
Dataset Title: Global Crop Condition and Commodity Production Analysis from the USDA/Production Estimates and Crop Assessment Division (PECAD)
Dataset Release Date: 2001
Dataset Release Place: Washington, D.C.
Dataset Publisher: USDA/FASOnline Resource: http://www.pecad.fas.usda.gov/cropexplorer/
Start Date: 1981-01-01
Latitude Resolution: 1/8 mesh grids
Longitude Resolution: 1/8 mesh grids
Temporal Resolution: daily, monthly, decadal
AGRICULTURE > AGRICULTURAL PLANT SCIENCE > CROP/PLANT YIELDS
AGRICULTURE > SOILS > SOIL MOISTURE/WATER CONTENT
AGRICULTURE > SOILS
ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE AIR TEMPERATURE
ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT
BIOSPHERE > VEGETATION > VEGETATION COVER
BIOSPHERE > VEGETATION > VEGETATION INDEX > NDVI
HUMAN DIMENSIONS > ECONOMIC RESOURCES > AGRICULTURE PRODUCTION
TERRESTRIAL HYDROSPHERE > SURFACE WATER > LAKES > RESERVOIRS
LAND SURFACE > LAND TEMPERATURE > LAND SURFACE TEMPERATURE
LAND SURFACE > LAND USE/LAND COVER > LAND PRODUCTIVITY
LAND SURFACE > LAND USE/LAND COVER > LAND RESOURCES
LAND SURFACE > SOILS > SOIL MOISTURE/WATER CONTENT
SPECTRAL/ENGINEERING > VISIBLE WAVELENGTHS > VISIBLE IMAGERY
CLIMATE INDICATORS > ATMOSPHERIC/OCEAN INDICATORS > PRECIPITATION INDICES > STANDARDIZED PRECIPITATION INDEX > WASP
CLIMATE INDICATORS > LAND SURFACE/AGRICULTURE INDICATORS > SATELLITE SOIL MOISTURE INDEX
ISO Topic Category
Quality Users are cautioned that this in Not Official USDA Data. Official
USDA production, supply, and distribution data are determined after
analyzing all available sources of data, including those provided on
Data Set Progress
Distribution Media: online WWW
Role: DIF AUTHOR
Email: bob.baldwin at usda.gov
USDA Foreign Agricultural Service CMP-PECAD, MS 1045-S 1400 Independence Avenue, SW
Province or State: DC
Postal Code: 20250
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Creation and Review Dates
Last DIF Revision Date: 2009-08-17