# Assessing the Potential of PlanetScope Imagery for Iron Oxide Detection in Antimony Exploration
## 5 Discussion
### Relative Comparison (Ratio Between BRs)  
The ratio between BR-PS and BR-Sentinel-2 was the only one to achieve significant values of absolute concordance. This is most likely due to their higher similarity in spatial resolution compared to the other satellites. When analyzing the individual BR results, we observed that both satellites identified very similar proportions of iron oxides, which explains why the ratio result was so positive. The BR-PS/BR-ASTER and BR-PS/BR-Landsat 9 ratios showed similar levels of disagreement. However, the ratio with BR-ASTER exhibited slightly higher disagreement and fewer positive values than the ratio with Landsat 9, which was unexpected given its higher spatial resolution (15 m) compared to Landsat 9 (30 m). This may be because BR-ASTER identified significantly more pixels in class 14 than the other satellites, and Figure 4i shows that many of these pixels correspond to regions with sparse vegetation. Although this issue could be resolved by applying a vegetation mask, this approach was deliberately avoided to assess the potential false positives that the ratios might produce. By not excluding vegetation pixels beforehand, it was possible to analyze the extent to which the spectral signal of vegetation could influence the results. This analysis provides valuable insights into the limitations and reliability of the method when applied to areas with significant vegetation cover. The ratio with Landsat 9 showed high levels of disagreement, with no cases of total agreement. However, compared to ASTER, it had more positive values and slightly lower disagreement. Some false positives involving vegetation were observed, particularly in class 12, but were less critical than those found with ASTER. When analyzing the ratio maps across the entire study area, it becomes evident that the PS results are much more like those of Sentinel-2 and ASTER. However, it is crucial to consider that differences in spatial resolution may have a significant impact, contributing to the higher levels of disagreement between PS and the results from ASTER and Landsat 9. Despite this, no anomalous values were observed, indicating that the discrepancies are primarily related to differences in spatial resolution rather than inconsistencies in detecting iron oxides. When analyzing only the areas of interest, a stronger relationship emerges between the level of result correspondence and the spatial resolution of the satellites. The data suggest that as spatial resolution decreases, non-correspondence increases. Sentinel-2 (10 m) shows the highest agreement with PS (3 m), followed by ASTER (15 m), and finally, Landsat 9 (30 m), which has the lowest correspondence. This confirms that the further a satellite's spatial resolution deviates from PS, the more different the results become due to increased pixel aggregation and spectral mixing. Despite ASTER's spatial lower resolution than Sentinel-2, its correspondence with PS significantly improves when focusing only on the areas of interest. This contrasts with the full-image analysis, where ASTER showed the lowest similarity with PS. A key factor contributing to this improvement is the absence of vegetation cover in the selected areas, which reduces spectral noise and potential misclassification. Landsat 9, with its 30 m of spatial resolution, shows the lowest agreement level with PS. Its higher percentage of non-correspondence may be attributed to the larger pixel size, which results in mixed spectral signals and a loss of finer details in iron oxide detection. Additionally, the fact that Landsat 9 consistently identifies a greater proportion of iron oxides compared to PS suggests potential overestimation due to its broader spectral bands and coarser resolution. While Sentinel-2 is the most comparable to PS, ASTER performs better in specific conditions, particularly in areas with minimal vegetation. On the other hand, Landsat 9'slower agreement underscores its limitations for fine-scale iron oxide mapping but may still be useful for broader regional assessments.