A NodeJS Express App that exposes a REST API for Accela and web tool at http://www.mapwnc.org

Buncombe County Property and City Jurisdiction GIS tables are copied nightly using Bedrock to a Postgres database.

Elevation contours generated from Lidar data for Buncombe County are also stored on the Postgres database.

The application calculates the "natural average slope" for a parcel or parcels of land (see the Section 7-12-4 of the City of Asheville's Unified Development Ordinance )

The slope calculation is costly and cannot be pre-calculated for the entire county (I think it takes like 24hrs to run once). So a sloperesults table is maintained on the Postgres database which contains the calculated slope, the parcel (or parcels) geometry, and some attribute data. At runtime, the application checks if a matching geometry exist in the sloperesults table for the input parcel or parcels geometry (this is fast with PostGIS); if a matching geometry exist then the existing calculated slope and attribute data is returned, if not, the slope is calculated and returned from the API, and a new record is added to the sloperesults table.

Runs as a Lambda function that wraps an Express App using serverless-express.

Usage

First run npm install

package.json has these scripts:

• Test Locally:
  • npm start (or for a Python program: npm run startpy)
• Deploy:
  • npm run deploy prod
  • npm run deploy dev
• Destroy: (removes all objects from AWS)
  • npm run destroy prod
  • npm run destroy dev
• Clean:
  • npm run clean (removes local temp files)