International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004 Int 
  
  
  
  
  
APP - AT1 APP - AT2 
RMS RMS X RMS Y RMS RMS X RMS Y N 
Mean 0.226 -0.005 0.202 0.142 -0.014 0.111 | 
St. Dev. 0.081 0.089 0.093 0.065 0.073 0.080 | 
  
  
  
  
  
  
  
  
  
Table III. Statistical parameters of the comparison from the ortophotos for Palermo project (in meters) 
Table II and relative figure 4 show overall statistics of residuals 
calculated for each considered configuration, in correspondence 
of the 33 surveyed CPs. A first control was made using APP 
data; the obtained results denote a high accuracy above all from 
an altimetric point of view. The following controls, made for 
the other provided configurations, confirm the good quality of 
the obtained results, with a sharp improvement of altimetric 
accuracy. 
Three digital orthophotos at scale of 2000 were produced, for 
APP, ATI and AT2 configurations. A first control of the APP 
orthophoto accuracy was carried out comparing the coordinates 
of an adequate number of points with those derived from the 
orthophotos related to other two configurations (tab. III). The 
obtained results are always much lower than those required for 
national map accuracy standards at scale of 1:2000. A further 
control was made placing the raster map at scale of 1:2000 over 
the APP orthophoto (fig. 5). 
3.2 The Catania project 
For the Catania area an automatic AT was executed by 
MATCH-AT software, determining for each photograph a 
several hundreds tie-points. A summary of the most relevant 
parameters of the automatic AT are shown in table IV. The AT2 
operation was done with 7 GCPs, using the remaining points as 
CPs. 
Table V shows the aggregate results of the comparison between 
the APP exterior orientation parameters and those calculated by 
AT software for different configurations taken into account. 
The obtained values are not much higher than those of Palermo 
project. 
Results of control made on the CPs (tab. VI e fig. 5) confirm the 
good quality of APP data; also in this case the increasing of the 
GCPs number does not generate a relevant improvement of 
accuracy. 
Finally, three digital orthophotos at scale of 200 were produced, 
for APP, ATI and AT4b configurations. Table VII shows 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
St. Dev. a priori Tie point generator 
N. photos 19 GCP X Y 2 [mj 0.030 0.030 0.050 N. of observations 17560 
N. strip 3 GPS X Y Z2 [mj 0.020 | 0.020 | 0.020 N. of unkows 6146 
Photo scale | 1:2000 INS omega phi kappa [grad] | 0.0050 | 0.0050 | 0.0050 | |Redundancy 11354 
Table IV. Parameters of the automatic AT (Catania project) 
X Y Z Omega Phi Kappa 
Mean -0.004 -0.037 -0.008 -0.0106 -0.0055 0.0093 
APP-AT1 
St. Dev. 0.024 0.025 0.035 0.0099 0.0047 0.0069 
Mean -0.069 -0.103 -0.066 0.0014 -0.0105 0.0223 
APP-AT2 
St. Dev. 0.204 0.017 0.068 0.0054 0.0163 0.0067 
Mean -0.006 -0.036 -0.008 -0.0103 -0.0052 0.0094 
APP-AT3a 
St. Dev. 0.024 0.024 0.035 0.0099 0.0047 0.0070 
Mean -0.005 -0.030 -0.009 -0.0077 -0.0050 0.0122 
APP-AT3b 
St. Dev. 0.029 0.022 0.035 0.0087 0.0048 0.0071 
Mean -0.004 -0.015 -0.003 -0.0075 -0.0062 0.0219 
APP-AT4a 
St. Dev. 0.041 0.027 0.031 0.0059 0.0046 0.0068 
Mean -0.005 -0.016 -0.004 -0.0079 -0.0057 0.0226 
APP-AT4b 
St. Dev. 0.042 0.027 0.030 0.0056 0.0046 0.0068 
  
  
  
  
  
  
  
  
  
  
Table V. Statistical parameters of the comparison from exterior 
Z, in meters — omega, phi e kappa in grad) 
578 
orientation parameters for Palermo project (X, Y,