Damage Assessment

This week, we looked at how to assess damage post-storms using aerial imagery. We compared raster files of a neighborhood in New Jersey from before and after Sandy. We had to assess damage done to properties based on these and rate it on a scale. We created a new feature class with points for each structure and including the information on damage and structure type in each point's tabular data. Next we looked at how close the structures were to the coastline, tallying the number of structures in each damage assessment based on location: 100m, 100-200m, 200-300m from the coastline. 

The pattern is very clear that the closer a structure was to the shoreline, the more likely it had major damage or was destroyed. The analysis shows that all structures within 300m of the coastline were at least affected by damage. The closer to the coastline a structure was, the more likely it was destroyed or had major damage. All destroyed structures were within 200m of the coastline and 83% of the major damage occurred within this distance as well. For those 200-300m from the coastline, over 90% of the damage was ranked as affected or minor. 

Structure Damage Category	Count of Structures 0-100 m from coastline	Count of Structures 100-200 m from coastline	Count of Structures 200-300 m from coastline
No Damage	0	0	0
Affected	0	9	10
Minor Damage	1	15	28
Major Damage	5	10	3
Destroyed	5	5	0
Totals	11	39	41

I think the aerial survey is a great method for a precursory look at what the damage could be, but I would hesitate to extrapolate overall damage without surveying a few more blocks using this method. Additionally, I think ground truthing is important to ensure quality control/quality assurance of the data. It was quite simple to see destroyed homes in the aerial, but judging minor vs major damage from sampling looking at if roofs are still intact is not going to give you the full picture of the impacts.