Statistical measures Sample Clauses
Statistical measures. Table 4-1 and Table 4-2 show height statistics figures for the CTX MER-A DTM from UCL and UoS. As described above, the HRSC DTM was resampled to fit to the data to be validated. Due to the different resolutions delivered between UCL and UoS, there is a discrepancy in the number of pixel elements evaluated. The UCL DTM (Table 4-1) has a height minimum that is 60 m lower in comparison to the HRSC DTM. In contrast the Maximum is 32 m higher in elevation than the maximum value of the HRSC DTM. As a consequence, the range of heights of the UCL DTM is 90 m larger compared to the HRSC DTM. This could be attributed to the better resolution the UCL DTM is provided in and thus the higher detail to be expected. However, the average height value is comparable with the HRSC DTM value and differs by only 6 metres. The observed standard deviation for the UCL CTX DTM is higher compared to the HRSC DTM. This could be due to the pattern observed that introduces additional noise to the scene. Another source for the higher standard deviation could be the increased detail of the CTX DTM in comparison to HRSC. Though, this appears to be unlikely since the observed effective resolution of the DTM is in the order of 75 m/pixel, as was reported in the previous section. Number of Elements: 4,593,037 4,593,037 4,593,016 Minimum [m]: -3891.83 -3951.59 -121.331 Maximum [m]: -3362.11 -3330.80 125.094 Height range [m]: 529.72 620.79 246.425 Average DN Value [m]: -3678.36 -3672.06 -6.29933 Standard Deviation [m]: 46.6395 54.9509 17.7338 The UoS DTM (Table 4-2), on the other hand, shows a comparable standard deviation with respect to the HRSC DTM. The minimum / maximum heights that are in a similar range to the height range of the HRSC DTM. Only the minimum height value is approximately 60 m below the minimum of the HRSC DTM. The source is seen in the bowl shape of the DTM and the noise in the central parts that have been observed in the colour overlay and the shaded relief. Number of Elements: 2,261,653 2,261,653 2,261,642 Minimum: -3891.82 -3951.42 -321.006 Maximum: -3362.09 -3361.91 106.930 Height range [m]: 529.73 589.51 427.936 Average DN Value: -3684.68 -3678.82 -5.85485 Standard Deviation: 45.6996 46.2945 24.9589 The equivalent figures for the HiRISE and its comparison with the validated CTX DTM are shown in Table 4-3. This indicates that there may be a height offset here which is not fully accounted for by the co-registration process. The standard deviation is very small. CTX DTM ...
Statistical measures. Table 4-6 and Table 4-7 show results of the statistical data analysis for the CTX MSL DTM from UCL and UoS. As described above, the HRSC DTM was resampled to fit to the data to be validated. Due to the different resolutions delivered between UCL and UoS, there is a discrepancy in the number of pixel elements evaluated. The resampling of the HRSC DTM causes only a slight change in the statistics (cf. 2nd column of both tables). The UCL DTM (Table 4-6) has a minimum that is much higher in elevation in comparison to the HRSC DTM. However, since the average height value is comparable with the HRSC DTM value and differs by only 2 meters, it is assumed that this difference in minimum height value can be attributed to outliers in either of the data sets. A similar effect can be seen for the maximum DTM values. A similar cause for the differences between the DTMs as for the minimum heights is considered. The observed standard deviation for the UCL CTX DTM is higher compared to the HRSC DTM. This could be due to the pattern observed that introduces additional noise to the scene. Another source for the higher standard deviation could be the increased detail of the CTX DTM in comparison to HRSC leading to many variations of the same order of magnitude. Number of Elements: 7072512 7072512 7072480 Minimum [m]: -5339.23 -4983.46 -499.283 Maximum [m]: -993.202 -1000.06 691.821 Height range [m]: 4346.028 3983.4 1191.104 Average DN Value [m]: -3623.88 -3625.72 1.838 Standard Deviation [m]: 946.427 950.700 49.105 The UoS DTM for the MSL landing site area (Table 4-7) shows very similar statistical data in comparison to the UCL statistical data when looking at the maxima, minima and height range. Though the average height/DN value is larger than the reference height from the HRSC by 175 meters indicating that there is a height offset whereas the UoS DTM is located higher than the HRSC DTM. Number of Elements: 4011309 4011309 4011309 Minimum: -5339.97 -4810.84 -680.760 Maximum: -909.96 -735.67 519.560 Height range [m]: 4430.01 4075.17 1200.320 Average DN Value: -3616.79 -3440.37 -176.415 Standard Deviation: 957.845 958.532 49.716 An assessment was also carried out of the HiRISE DTM compared with the one from CTX. This is shown in Table 4-8. HiRISE and coincident CTX DTMs for the MSL test site. and displays a very small bias (≤0.5m) and standard deviation of 5m Number of Elements: 141,207,925 141,207,925 141,201,637 Height range [m]: 379.01 404.49 128.277 Average Height [m]: -4...