200 partially processed MSS scenes per day for transmission 
to the EROS Data Center (EDC) in Sioux Falls, South Dakota 
for further dissemination. Data will be available to EDC 
within 48 hours of acquisition by the ground segment. 
The Landsat-4 Ground Processing System will generate all of 
the geometric correction matrices that are appended to the 
partially processed data transmitted to the EROS Data 
Center. The Ground Segment can also apply these same cor 
rections to selected quality assurance output products to 
ensure that output products are accurate. 
The new Thematic Mapper (TM) instrument on board Landsat-4 
and the corresponding ground processing system will be 
operated for several years in a research mode with only 
limited film products and computer compatible tapes in the 
public domain. In July of 1983, up to 12 scenes will be 
fully processed per day and the additional raw TM data ac 
quired by the spacecraft will be stored on tape. All film 
and CCT products will be fully corrected both geometrically 
and radiometrically. 
Table 2 compares several of the more salient features of 
the MSS and TM instruments. In January of 1985, TM pro 
duction capacity is intended to increase to 50 fully pro 
cessed scenes per day. Due to the relative unavailability 
of TM data, over the near term, the remainder of this sec 
tion only discusses Landsat-4 MSS image processing and 
compares it to earlier Landsat digital processing. 
The Landsat-4 mission design was constrained to be as 
transparent as possible for current MSS users, but several 
modifications were necessary. Data formats remain essen 
tially the same as Landsat 2 and 3, image framing and co 
verage have been modified, and both geometric accuracy and 
the radiometric correction accuracy have been improved. 
DATA FORMATS 
The format of the image data transmitted to EDC from the 
NASA/NOAA Ground Segment has been constrained to be essen 
tially the same as Landsat 2 and 3 data. This allows the 
EDC processing system that applies the geometric correc 
tions and generates the user output products to remain 
unchanged. Some additional quality information has been 
included in previously unused data fields to provide better 
management information and knowledge of prior processing 
quality.