pwaLUPMIS2/etl/README.md
ekke da6f968725 Zonal-statistics Excel export, COG layer entry point, DE Africa ETL
Excel export (from TWG feedback)
- src/analysis/xlsx.js: a dependency-free XLSX writer — an .xlsx is a ZIP of
  XML, so this packs the required parts with a small stored-ZIP writer. Avoids
  SheetJS (stale npm package with advisories) and ExcelJS (heavy for an
  offline-first field app), and does not rely on the JSZip that only reaches us
  transitively via shp-write. Lazy-loaded as a ~5.6 kB chunk.
- After a zonal run the Analysis panel offers "Export table (Excel)", writing a
  two-sheet workbook: Results (figures as real numbers) and Parameters (zone
  and input layers with feature counts, the "Apply to" scope, membership rule,
  statistics, numeric field and export time) — so a table can be verified or
  reproduced later rather than being an unattributed set of numbers.
  The button is hidden for overlay runs and cleared when the mode changes.
- Verified against two independent readers: openpyxl loads it with zero
  warnings and correct numeric types, and LibreOffice Calc opens it as a
  spreadsheet. Also exercised end-to-end through the real zonal pipeline.

COG raster entry point
- Add External Layer gains a COG type alongside WMS/WFS/XYZ, with a URL
  pre-flight check that distinguishes a web page, a 404, a CORS block and a
  server without byte-range support — geotiff.js otherwise reports these only
  as an opaque "AggregateError: Request failed".

Digital Earth Africa ETL
- etl/deafrica_dem_to_minio.py exports a DE Africa DEM for a district as a COG
  and uploads it to the LUSPA MinIO bucket raster-objects, then verifies the
  object is anonymously readable and range-capable. Credentials come from the
  environment; the existing PHP integration hardcodes them and an earlier key
  pair reached Gitea. NOTE: not yet run against the Sandbox — start with
  --list-products to confirm the DEM product name.

Documents
- Concept note: Digital Earth Africa added as a raster source (§6.3), separating
  the live WMS route from the batch Sandbox export; corrected the in-house
  contour table's provenance to OpenTopography (gdal_contour over an SRTM 30 m /
  Copernicus 30 m DEM), and added the ToR §2.4.2 / FS §2 alignment chapter.
- TWG presentation, architecture and two integration workflow charts (SVG
  sources kept in the repo so they stay editable), and a user guide for the
  Analyse tools.

Service worker v13 -> v14. .gitignore: exclude Python bytecode from etl/.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-23 16:28:45 +02:00

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Markdown

# LUPMIS2 raster ETL
One-off batch jobs that prepare raster data for LUPMIS2 and publish it to the
LUSPA MinIO object store, from where the PWA streams it as a Cloud-Optimized
GeoTIFF (COG).
This mirrors the existing OpenTopography contour workflow: a **preparation
step run occasionally**, not a live connection from the app.
```
DE Africa (Sandbox) → write_cog() → MinIO raster-objects → LUPMIS2 map
```
## Target infrastructure
| | |
|---|---|
| S3 API endpoint | `https://minioapi.lupmis4luspa.org` (path-style) |
| Bucket | `raster-objects` (anonymous read enabled) |
| Console | `https://minio.lupmis4luspa.org` — admin UI only, **not** the API |
Verified working for COG streaming: anonymous unsigned `GET` returns 200,
range requests return `206 Partial Content`, and CORS allows the PWA origin
with `Range` on preflight and `Content-Range` exposed.
## Credentials
Supplied via environment variables — **never** hardcode them:
```bash
export MINIO_KEY=...
export MINIO_SECRET=...
```
The PHP integration under `FromKwesi/minio-uploads` embeds its keys in source,
and an earlier key pair was committed to Gitea. Keep these out of git.
## `deafrica_dem_to_minio.py`
Exports a Digital Earth Africa DEM for an area of interest and uploads it.
Run it in the **DE Africa Sandbox** — the Open Data Cube is configured there.
Locally, DE Africa's docs note that `dc.load` / `load_ard` need additional
configuration (a database), so the Sandbox is the lower-maintenance choice.
```bash
# 1. confirm which DEM products exist before the first real run
python deafrica_dem_to_minio.py --list-products
# 2. export + upload a pilot district
python deafrica_dem_to_minio.py --district koforidua
# preferred for production: clip to the authoritative boundary
python deafrica_dem_to_minio.py --geojson koforidua.geojson --name koforidua
# inspect the output without uploading
python deafrica_dem_to_minio.py --district tamale --dry-run
```
The script writes `<name>_dem.tif`, uploads it to `dem/<name>_dem.tif`, then
verifies the public URL really is anonymously readable and range-capable. It
also emits `<name>_dem.manifest.json` recording the URL, product, bbox, CRS and
resolution.
### Loading the result in LUPMIS2
**Add External Layer → COG →** paste the object URL, e.g.
```
https://minioapi.lupmis4luspa.org/raster-objects/dem/koforidua_dem.tif
```
### Notes and caveats
- **Preset district bounding boxes are approximate.** Use `--geojson` with the
real district boundary from PostGIS for anything beyond a first test.
- **Output CRS defaults to EPSG:3857** so the browser does no reprojection.
For Stage 3 hydrology and slope, re-export in a metric CRS (UTM 30N =
`EPSG:32630` west, 31N = `EPSG:32631` east) — Web Mercator distorts distance
with latitude and will bias slope and flow-accumulation results.
- **Verify the product name** with `--list-products` first. The default is
`dem_srtm`; DE Africa also publishes derivatives (`dem_srtm_deriv`), which is
the source of the slope WMS layer LUPMIS2 already consumes.