How Does Site Locator Work?

There are 3 steps to generating a site location report.

• Translate the street address to a latitude/longitude coordinate (Geocode the address)
• Calculate census blocks that fall within the defined radius
• Create the demographic report for the area within the radius

Geocoding the Address - We use our GeocodeCD to determine the latitude/longitude of the address. From this engine we are able to calculate the exact latitude and longitude of addresses in the US. For more information about this product, click here.

Then we check every block to see whether or not it's centroid (latitude/longitude mid-point of the block) falls within the radial circle around the site location that you have chosen. Once every block within the radius has been selected, we then weigh it to the block group.

In order to create the most precise answer, we calculate the area covered by using census blocks-the smallest geography at which census data is collected. There are over 8.2 million census blocks in 2000. However, the Census Bureau does not release most of these demographics (such as income, housing value, education, employment, etc.) at the census block, but only down to the block group level.

Within the radius many of the block groups may be fully covered, but on those block groups at the edges of the circle there are often only partial coverage. If we were to use the block group as the boundary there would be some block groups whose centroid is within the radius, but whose area is only partially included and other areas that are not covered because the block group in that location has a centroid that falls outside of the radius. Thus to make a more precise circle we use the blocks and then weigh the percent of the population in each block that is within the radius to the population in its block group.

Finally, we pull the data at the block group level for the variables in the product and weigh the data by the block population covered within the radius. Then we sum up the data and variables to present it in an easy to ready site report.