Accuracy: 
1) 
2) 
Table I 
Editing was made during every stage of map production. A minimum of ten (10) percent of map 
quadrangles produced was field checked for accuracy with precise traverse survey on prominent 
ground features. The results of field check are list below. 
Photo Basemaps of Tai-Chung City 
Map scale: 
Number of map quadrangles produced: 
Number of map quadrangles field checked: 
Number of ground features field checked: 
1:5,000 
5O maps 
5 maps 
15 points 
Discrepancies of horizontal coordinates and elevations of ground features between that of the maps and field 
surveys: 
X variance 
Maximum 
Minimum 
12.2 cm 
Y variance Z variance 
18.5 cm 
141.7. cm 
0.3 cm 0.2 cm 0.3 cm 
Average 6.3 cm 6.0 cm 9.4 cm 
Orthophoto of Tai-Chung Harbor 
Map scale: 
Number of map quadrangles produced: 
Number of map quadrangles field checked: 
Number of ground features field checked: 
  
1:10,000 
16 maps 
5 maps 
18 points 
Discrepancies of horizontal coordinates and elevations of ground features between that of the maps and field 
surveys: 
X variance 
Maximum 
57.2 cm 
Y variance Z variance 
58.9 cm 48.8 cm 
Minimum 0.9 cm 2.3. cm 6.4 cm 
27:6 cm 
Average 
29.0 cm 
  
30.6 cm 
372 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996