Control base and RBV Subscene Enlargement 
Adjusted ground coordinate values for all points resulting 
from the block adjustment program were plotted at 
1:100,000-scale as a control base, using a Gerber 1232 
Flatbed Plotting System. The program also computed 
individual transformation parameters which were subse 
quently used to calculate precise scale factors for 
enlargement of each subscene to 1:100,000-scale. The four 
subscenes were each enlarged by their factors using a 
Langston E-4 enlarging camera. The enlarged subscenes 
were then individually overlayed to the control base by 
registering the marked points on each image to 
corresponding points plotted on the base. 
Accuracy Test of Mosaic 
The four enlarged subscenes were photomechanically 
mosaicked together at 1:100,000-scale. An accuracy test 
was then performed by measuring the marked control points 
on the mosaic using an Altek AC-34 digitizing table. Of 
the 47 original points, 32 points lay within the bound 
aries of the proposed map area. The 32 measured points 
were mathematically adjusted to the State plane coordinates 
using the similarity transformation. Computed residuals 
for each point were compared to residual errors for 
respective points on the original subscenes from the block 
adjustment program. There was no significant difference 
in direction of residuals between the points on the 
original 1:500,000-scale subscenes and on the enlarged 
subscene mosaic at 1:100,000-scale. The similarity trans 
formation resulted in an RMSE of 50 meters for the 32 
points covering the proposed map area. 
REVISION 
Landsat 3 RBV images have been tested as a map revision 
tool. The Marion, Ohio; Vidalia, Georgia; and Inverness, 
Florida, 1:100,000-scale topographic quadrangles were 
revised with the aid of RBV imagery. These particular 
maps had recently undergone significant changes in various 
natural and manmade features. 
In each case the maps had been scheduled for revision to 
meet National Map Accuracy Standards. Under current U.S. 
Geological Survey map revision policy, these maps were to 
undergo revision using 1:80,000-scale quad centered photo 
graphs. Each of the 32 photographs that cover a 1:100,000- 
scale map is reduced to a 1:100,000-scale film transpar 
ency. However, in these three quadrangles there were 
areas where gaps in photographic coverage existed. The 
revision policy allows for the use of special source 
material when adequate photographs are not available. 
Therefore, rather than let these maps remain dormant new 
map information was added solely from the Landsat 3 RBV 
imagery. 
The RBV system has an effective resolution of 30 meters. 
The enlargement of Landsat 3 RBV Imagery to 1:100,000-scale 
can be accomplished without significant loss of resolution 
and detail.