Lidar Advantages and Limitations

Airborne lidar offers detailed and accurate elevation measurements that can be used to help classify wetlands and associated habitats more accurately than classifications based on aerial photographs alone. Comparisons of photographically mapped NWI units with lidar-derived topographic profiles across Mustang Island show that topographic detail achieved with lidar allows more detailed discrimination of wetland and upland units than appears on NWI maps. Further, some NWI units on both island transects are misclassified; some units mapped as wetland are more likely to be upland, and some units mapped as upland are more likely to be wetland habitat. Comparisons of lidar-derived elevations with coastal environments identified during the field survey show similar levels of detail, suggesting that lidar data could be used to map coastal environments at the same level achievable with labor-intensive ground-based surveys. Used with aerial photographs, lidar-derived elevations can be used to help distinguish coastal environments as well as upland, palustrine, estuarine, and marine habitats that may have ambiguous photographic signatures.

Most NWI habitats and coastal environments have statistically distinct average elevations, but rather wide elevation ranges that overlap to varying degrees with other habitats and environments. Further, lidar may not penetrate to the ground surface in densely vegetated areas, producing an anomalous elevation at those points that may be significantly higher than the actual elevation and lead to potential misclassification of habitat or environment.