LandScan Squares

This data is derived from FEMA/ONL LandScan raster data- using the CONUS nighttime data for 2021( https://landscan.ornl.gov/ ). The raster produced by ONL has 3 arc-second, or just over 90m grid cells. Each cell contains an estimate of the nighttime population within that cell. That LandScan raster was converted to vector polygons. Grid cells with zero estimated population are removed. These were intersected with Census block groups to transfer the containing block group GEOID where "centers within." They were also intersected with DWR BAM flood plain shapes ( https://gis.bam.water.ca.gov/bam/ ), resulting in two indicating columns- 100 and 500 year, also, “centers within.” The resulting data can be used to develop statistics to represent the estimated number of people living (nighttime) in identified flood plains.