Overview

In 1999, the USDA Economic Research Service released a report examining the relationship between natural amenities and rural population change. The study introduced a Natural Amenities Scale to evaluate and rank environmental qualities across counties in the contiguous United States.

The study combines multiple environmental factors selected for simplicity, availability, lack of redundancy, correlation to population change, and influence on perceived public desirability. These variables were standardized into a composite score, which was then used to derive an ordinal classification rank from 1-7 (1 = least natural amenities/desirable, 7 = most natural amenities/desirable).

Note that the Natural Amenity Scale is merely a statistical model of environmental preference; it does not provide an absolute measure of regional desirability. Interpretation of results may be subject to personal bias.

Data Source & Variables

The Natural Amenities Scale is based on data from 1941-1970, aggregated at the county level. Each attribute value represents the average of a desirable environmental factor over the entire time range. Precise attribute descriptions are given by the USDA. Below is a summary of the descriptions:

• Warm Winters: average January Temperature
• Winter Sun: average January hours of sunlight
• Temperate Summers: average July Temperature
• Summer Humidity: relative humidity in July
• Topographic Variation: ordinal landform diversity class (derived from a 21-category topography scale based on dominant landform types and variation within each county); higher classes reflect more varied and mountainous terrain and contributed more to the composite standardized score
• Water Area: proportion of county covered by water (capped to reduce coastal bias, log-transformed and standardized as a z-score)

This Project

The data for this project was aggregated from the original county-level values to state-level averages. These values are mapped across the choropleth and coordinated bubble chart visualizations above.

Use the map to compare natural amenity patterns across states. For example, locate the states that experience the fewest hours of winter sunlight (hint: look at the Pacific Northwest). Use the chart to explore relationships between natural amenities. For example, select standardized topography, January temperature, and July temperature from the three dropdowns above. There is a cluster of states with a higher topographic variation score around cooler winter and summer temperatures. What insights could be generated from this observation?

Take your time to explore all the attribute combinations. Do any of the natural amenity scores or ranks take you by surprise? How does your state measure up against its neighbors?

Classification

In this state-aggregated dataset, variables are expressed as averages, percentages, or standardized z-scores. The CKMeans clustering method was applied to preserve natural groupings and to reduce the influence of differing measurement scales across variables. Because the classified natural amenity rank (1-7) does not fit cleanly within the CKMeans clustering classification scheme, it is instead presented as a discrete ordinal category within the clicked state popups.

Closing Notes

This dataset reflects natural amenity scores measured according environmental conditions from the mid-20th century (1941-1970). Changes in climate and land use may alter how these scores would be measured today. Further research is strongly encouraged.

Data can be easily accessed from the USDA's website using the following link: Natural Amenities Scale

U.S. States Shapefile accessed from the Project Linework webpage (Editors: Daniel P. Huffman, Hans van der Maarel. Shapefile Name: Times Approximate). For this project, I selected the contiguous U.S and reprojected the shapefile to WGS 84 in ArcGIS Pro. I then converted the shapefile to topojson format with MapShaper.