SVI-Population Project

An ArcGIS Python project for generating Social Vulnerability Index (SVI) glyph maps with raster-based population data visualization.

Overview

This project processes CDC Social Vulnerability Index (SVI) data alongside population data using the U.S. National Grid (USNG) system to create detailed vulnerability visualization maps at 100-meter grid resolution.

Features

• Spatial Data Processing: Integrates 100m USNG grids with CDC SVI tract data
• Population Filtering: Selects areas with population greater than 0
• Multi-Theme SVI Analysis: Processes four CDC SVI themes:
  • Theme 1: Socioeconomic Status
  • Theme 2: Household Composition & Disability
  • Theme 3: Minority Status & Language
  • Theme 4: Housing Type & Transportation
• Glyph Map Generation: Creates color-coded visualizations based on RPL (Ranking Percentile) scores
• Automated Workflow: Geodatabase creation, spatial joins, and field calculations

Requirements

Software

• ArcGIS Desktop/Pro with Python support
• ArcPy library

Input Data

• 100m USNG Grid: State-specific 100-meter USNG grid feature classes
• CDC SVI Data: County/tract-level SVI shapefiles from CDC/ATSDR
• Population Data: Gridded population data at 20m or 100m resolution

Project Structure

SVI-Population/
├── src/
│   └── SVI_Glyph_Map_Raster.py    # Main processing script
└── README.md                       # This file

Usage

Basic Execution

from SVI_Glyph_Map_Raster import SVIGlyphMapRaster112

# Define input parameters
usng_grid = "path/to/State_USNG_100m"
svi_data = "path/to/SVI2018_STATE_tract.shp"
pop_data = "path/to/State_USNG_20_Pop"
output_folder = "path/to/output/folder"

# Run the analysis
SVIGlyphMapRaster112(
    Input_100m_USNG_Grid_File=usng_grid,
    Input_CDC_SVI_tract=svi_data,
    Input_Population_Data=pop_data,
    Processing_and_Output_Folder_Location=output_folder
)

Output Structure

The script creates:

• Processing Geodatabase: SVI_Processing.gdb
• Feature Classes:
  • Pop_100m_USNG: Population-filtered USNG grids
  • Pop_100m_USNG_SpatialJoin: USNG grids joined with population
  • USNG_100m_SVI_SpatialJoin: USNG grids joined with SVI data
  • Summary_Statistics_RPL_USNG1km: Aggregated RPL statistics at 1km
  • Summary_Stats_USNG1km_SVI_100m_SpatialJoin: Final joined dataset with color codes

Data Processing Workflow

1. Environment Setup: Creates output folder and processing geodatabase
2. Population Filtering: Selects USNG cells with population > 0
3. Spatial Joins:
   • Joins 100m USNG grid with population data
   • Joins result with CDC SVI tract data
4. Grid ID Calculation: Generates unique grid identifiers
5. Statistical Summarization: Calculates mean RPL values at 1km resolution
6. Color Coding: Assigns color codes based on RPL thresholds:
   • 0 - 0.25: Low vulnerability
   • 0.25 - 0.50: Moderate vulnerability
   • 0.50 - 0.75: High vulnerability

   • 0.75: Very high vulnerability

Coordinate System

• Projection: WGS 1984 Web Mercator Auxiliary Sphere
• Cell Size: MINOF (minimum of inputs)
• Output Coordinate System: WGS 1984 Web Mercator Auxiliary Sphere

Notes

• Generated by ArcGIS ModelBuilder on 2025-11-10
• Original paths reference Alabama (AL) as example state
• Script supports processing any U.S. state with appropriate input data
• Requires adequate disk space for geodatabase operations