Raster QA/QC Viewer

This is a standalone Shiny app for browsing CCL_layers raster outputs stored in S3. It's intended to make QA/QC easier.

What it does

• Lists tiles for a selected city / aoi / infrastructure / scenario
• Lists available ccl_layers/*.tif rasters under that scenario
• Loads and merges the selected raster across tiles
• Displays the raster on an interactive map with pan, zoom, identify, and optional satellite basemap
• Optionally overlays a vector file from an HTTP geojson or json URL
• Shows summary statistics plus a density plot for continuous rasters or a histogram for nominal rasters

Requirements

• R
• Internet access to the public wri-cities-tcm bucket

Run

From this folder:

Rscript run_app.R

Alternative launch

If you prefer an interactive R session:

source("run_app.R")

Instructions

1. Choose a city from the dropdown--the aoi name will auto populate.
2. Choose an infrastructure from the dropdown—-the scenario name will auto populate.
3. Click 'List available layers'. The Layer dropdown will populate with the raster layers in the ccl_layers tile folders.
4. Choose whether the raster should be rendered as continuous or discrete.
5. Optionally add a URL pointing to a geojson layer like a boundary.
6. Choose the basemap.
7. Click 'Load selected layer' to add the layer to the map. It has to load and merge the layer for all tiles, so it takes a minute, but your patience will be rewarded.
8. The raster will display in the map, alongside summary statistics and a density plot for continuous rasters and a histogram for discrete raster. You can also click on the map and the pixel value will be displayed in the box at the lower left of the page.

Repo contents

• app.R: the Shiny app
• R/s3_helpers.R: local copies of the helper functions needed for list_tiles() and load_and_merge()
• .Rprofile: intentionally inert so opening the repo has no side effects
• run_app.R: installs missing packages and launches the app

Notes

• The app reads rasters and lists scenario contents directly from the public S3 bucket over HTTPS.
• The map is displayed in leaflet-friendly lon/lat coordinates, but identify queries are still run against the loaded raster values.