Parcel Elevation FAQ
What are the Elevation attributes?
- Roughness Rating: a score representing the variability in elevation within a parcel
- Highest Parcel Elevation: The highest elevation present on a parcel reflected in meters above sea level
- Lowest Parcel Elevation: The lowest elevation present on a parcel reflected in meters above sea level
What is the source of the elevation data?
The elevation data for each parcel is being created using the USGS 10 meter Digital Elevation Model (DEM) https://data.usgs.gov/datacatalog/data/USGS:3a81321b-c153-416f-98b7-cc8e5f0e17c3
Are the elevation attributes specific to the parcel?
Yes, the elevation attributes are specific to each parcel
Who created the elevation attributes?
Esri and Regrid worked together to create the parcel level elevation attributes
What is the methodology used to create the elevation attributes?
- Elevation values for each parcel are calculated using a zonal statistic operation where parcels were first converted into internal zone rasters based on unique id (ll_uuid), and then those zones were used to extract minimum and maximum elevation attributes from the Digital Elevation Model
- Roughness was calculated by measuring the elevation change of a grid cell from its eight neighboring cells (Riley et al. 1999) and classified into seven classes from 0 (Level) to 6 (Extremely Rugged)
How frequently are the elevation attributes updated?
Regrid intends to work with Esri on an annual basis to update the elevation data. Regrid is still working with Esri to determine at what cadence this process will be re-run to incorporate new parcels and the necessary recalculation of adjusted parcels