A major effort was initiated in the fall of 1974 by the National 
Aeronautics and Space Administration, Johnson Space Center (NASA/JSC) 
with the cooperation of the U.S. Dept. of Agriculture (USDA) to acquire 
fully annotated and calibrated multitemporal sets of spectral measure- 
ments and supporting agronomic and meteorological data [2]. The Purdue 
University, Laboratory for Applications of Remote Sensing (Purdue/LARS) 
was responsible for the technical design and coordination of the exper- 
iment. 
    
  
  
  
  
  
   
  
   
  
  
  
   
  
  
  
  
  
  
  
  
  
  
    
  
  
  
  
  
  
  
   
  
  
  
  
  
  
  
  
  
  
    
Spectral, agronomic, and meteorological measurements were made at 
three LACIE test sites in Kansas, South Dakota, and North Dakota for 
three years. The remote sensing measurements include data acquired 
by truck-mounted spectrometers, a helicopter-borne spectrometer, air- 
borne multispectral scanners, and the Landsat multispectral scanners. 
These data are supplemented by an extensive set of agronomic and 
meteorological data acquired during each mission. 
The LACIE Field Measurements data form one of the most complete 
and best documented data sets acquired for agricultural remote sensing 
research [3]. Thus, they are well-suited to serve as a data base for 
research to (1) quantitatively determine the relationship of spectral 
to agronomic characteristics of crops, (2) define future sensor systems, 
and (3) develop advanced data analysis techniques. The data base is 
unique in its comprehensiveness of sensors and missions over the same 
sites throughout the growing season and the calibration of all multi- 
spectral data to a common standard. 
Experimental Approach and Rationale 
Spectral, agronomic, and meteorological measurements for the 
field measurements project were made at three LACIE test sites during 
the 1975, 1976 and 1977 crop years. The sites are in Finney County, 
Kansas; Williams County, North Dakota; and Hand County, South Dakota 
(Figure 1). Finney and Williams Counties were chosen to represent 
winter and spring wheat growing areas, respectively. Both winter and 
spring wheat are grown in Hand County. Data were collected at the 
sites for three years to obtain a measure of the year to year variation 
in growing conditions and their influence on spectral response. 
The primary sensors were truck-mounted spectrometers, a helicopter- 
borne spectrometer, an aircraft multispectral scanner, and Landsat-2 
multispectral scanner. Each sensor system has unique capabilities for 
acquiring spectral data. The spectrometer systems produce the highest 
quality reflectance measurements, but provide only limited measurements 
of spatial variability. On the other hand, an aircraft scanner provides 
spatial sampling of the scene and can obtain data at multiple altitudes, 
but its spectral coverage is limited to a fixed set of wavelength bands. 
The helicopter and aircraft data acquisition systems have the advantage 
of flexible scheduling and, therefore, provide greater opportunity to 
obtain cloud-free data at critical crop growth stages than the Landsat