Demographic

Demographic FAQ

What is the source of the demographic data?

The demographic information is coming from Esri. Esri’s Demographic team performs annual custom processing beginning with data made available by the US Census Bureau, and adding many additional sources for a comprehensive and time focused content set. These additional sources include but are not limited to; Postal, Construction, Permits, and consumer behavior data. You can read more about Esri’s demographic data here

Detailed metadata and methodology information related to Esri's Demographics can be found here

What is CAGR?

CAGR stands for Compound Annual Growth Rate and is represented within the data as a percent. Simply put, CAGR allows a clean presentation of data across multiple years

Technically CAGR is defined as: A business term representing the mean annualized growth rate for compounding values over a given time period. CAGR smooths the effect of volatility of periodic values that can render arithmetic means less meaningful. It is particularly useful to compare growth rates of various data values over time

How granular is the demographic data? Is it specific to each parcel?

The demographic data is not specific to each parcel. The demographic data is aggregated at the Census Block Group level which is the lowest level the US Census Bureau reports demographic data for and contains between 600 and 3,000 people (this represents between 250 and 550 housing units)

When is the demographic data Updated?

The demographic data is updated annually and is generally updated in late June or early July and reflects data from the previous year (for example, in July of 2024, the data is reflecting 2023 vintage data) Regrid performs backfill of the Demographic data to new parcels, created through our parcel update process, on a monthly basis.

Who performed the calculation on each field?

The Esri Demographic Team is the source of the data and performed the necessary calculations to arrive at the values utilizing data from a wide variety of input sources

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

Risk Rating FAQ

What is the Risk Rating?

The risk rating is a single value to describe a properties level of risk from hazards based on three area:

• Expected Annual Loss (EAL) is the natural hazard(s) risk component and associated expected financial impact
• Social Vulnerability measures the susceptibility of social groups to the adverse impacts of natural hazards
• Community Resilience measures a community’s ability to prepare for, adapt to, withstand, and recover from the effects of natural hazards.

What is the source of the Risk Rating data?

The source of the Risk Rating attribute is from the National Risk Index that is maintained by FEMA. More information is available here: https://hazards.fema.gov/nri/learn-more Detailed technical information is available here: National Risk Index Technical Documentation

Are more data attributes available from the National Risk Index?

Yes, while Regrid is only adding the overall Risk Rating attribute to our Parcel Data Premium Schema there are over 400 additional data elements contained within the National Risk Index. These additional data elements can be accessed through the National Risk Index data directly.

What natural hazards are included to form the Risk Rating?

There are 18 natural hazard components that are utilized together within the Risk Index to arrive as the Risk Rating:

What does Social Vulnerability mean?

Social Vulnerability is broadly defined as the susceptibility of social groups to the adverse impacts of natural hazards, including disproportionate death, injury, loss, or disruption of livelihood. Social Vulnerability considers the social, economic, demographic, and housing characteristics of a community that influence its ability to prepare for, respond to, cope with, recover from, and adapt to environmental hazards

What does Community Resilience mean?

Community Resilience is defined by National Institute of Standards and Technology (NIST) as the ability of a community to prepare for anticipated natural hazards, adapt to changing conditions, and withstand and recover rapidly from disruptions

Is the risk rating data specific to each parcel?

No, the Risk Rating is calculated at the Census Tract level and populated to each parcel

What are the values that will be returned with the Risk Rating and what do they mean?

• Very High = 80th to 100th percentile
• Reasonably High = 60th to 80th percentile
• Relatively Moderate = 40th to 60th percentile
• Reasonably Low = 20th to 40th percentile
• Very Low = 0 to 20th percentile

When is the Risk Index updated?

The National Risk Index team at FEMA continuously updates the National Risk Index as new data become available and improved methodologies are identified. FEMA has committed to providing regular updates to the National Risk Index but does not publish a schedule or calendar. An annual to 18 month refresh of the Risk Rating is likely.

Regrid performs backfill of the Risk Rating to new parcels, created through our parcel update process, on a monthly basis. These updates use the then current data, not new data from FEMA.

Transmission Line Distance Data FAQ

What does distance to transmission line represent?

Distance to transmission line is calculated for each parcel and represents the distance (in meters) that the parcel lies from the nearest ‘relatively high voltage’ (‘relatively high voltage’ = 69kv - 765kv) electric transmission line as reflected in the dataset maintained by the Homeland Infrastructure Foundation-Level Data (HIFLD) for transmission lines More on that transmission line dataset can be found in HIFLD

What is the source of the distance to transmission line Data?

Esri utilized the combination of the Regrid parcel data and the HIFLD transmission line data to calculate the distance from each parcel to the nearest relatively high voltage electric transmission

Is the distance to transmission line specific to each parcel?

Yes, the distance to calculation is specific to each parcel

What is the methodology to calculate the distance to transmission line?

The distance to transmission line is calculated by assessing the entire polygon geometry of each parcel and calculating the distance to every transmission line within 100 miles of the parcel.The smallest distance value for each parcel/ll_uuid is then assigned as this value. Distances are calculated using a planar distance method (in meters) after projecting both parcels and transmission lines to an appropriate equidistant coordinate system

When is the distance to transmission Line data updated?

Regrid does not control the HIFLD data but it appears this data will be updated on an annual basis, likely in the first quarter of each year. Regrid is working with Esri 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