IWMIHQ/madagascar_seasonal_water_accounting

Madagascar Seasonal Water Accounting

Seasonal water accounting for Madagascar at ~1 km: rainfall, total ET, green and blue ET, water yield and runoff, for each of two cropping seasons, averaged over 2003-2021. Water Accounting Plus output rebuilt from IWMI's Africa GeoPortal tile services, which serve no downloadable raster.

• Region Madagascar
• Period 2003-2021
• Theme Water accounting
• Grid EPSG:4326, 762 x 1433 at 0.009521931 deg (~1060 m)
• Bands 12
• Files 12 Cloud-Optimised GeoTIFFs under data/, named <band>.tif, one per band

Bands

Band	Type	Units	Nodata
s1_rainfall	float32	mm	-9999.0
s1_et	float32	mm	-9999.0
s1_rainfall_et	float32	mm	-9999.0
s1_incremental_et	float32	mm	-9999.0
s1_water_yield	float32	mm	-9999.0
s1_runoff	float32	mm	-9999.0
s2_rainfall	float32	mm	-9999.0
s2_et	float32	mm	-9999.0
s2_rainfall_et	float32	mm	-9999.0
s2_incremental_et	float32	mm	-9999.0
s2_water_yield	float32	mm	-9999.0
s2_runoff	float32	mm	-9999.0

Read it

These are COGs, so GDAL reads them in place over HTTP -- no full download, and a windowed read fetches only the bytes it needs:

from huggingface_hub import hf_hub_url
import rasterio

url = hf_hub_url("IWMIHQ/madagascar_seasonal_water_accounting", "data/s1_et.tif", repo_type="dataset")
with rasterio.open(url) as src:
    print(src.width, src.height, src.crs, src.nodata)
    patch = src.read(1, window=((0, 256), (0, 256)))

Or pull the whole repo:

from huggingface_hub import snapshot_download
path = snapshot_download("IWMIHQ/madagascar_seasonal_water_accounting", repo_type="dataset")

Read this before using it

This is a 2003-2021 AVERAGE, not a time series, and the dataset datetime spans that period only to record it. Every cell is a 19-year mean for its season, so nothing here describes a particular year and no trend can be taken from it. The evidence for the averaging is the source's own naming: the sibling published items are "Seasonal Maps of Madagascar (2003 - 2021)" and every layer carries an "Average" tag. The season boundaries are undeclared. Nothing in the service metadata, the DCAT feed or the ArcGIS item records says which months either season covers, so s1 and s2 cannot be aligned to a calendar or compared against another dataset's seasons. What is known is measured rather than assumed: s2 is much the wetter, at a mean 1,204 mm of rainfall against 241 mm for s1. These rasters were rebuilt from a tile cache, not downloaded. The service refuses exportImage, so the values here are whatever was published into the LERC pyramid, at the one pyramid level that matches the service's native resolution. LERC is lossless and both WA+ identities close to float32 precision, so the reconstruction is sound -- but it is a copy of a cache, and the ArcGIS service recorded in each file's source tag remains the authority. Runoff has a different footprint from the other ten bands: 555,659 valid cells against 556,286, so 627 cells carry rainfall and ET but no runoff. Do not assume one mask across the product; mask each band on its own nodata. Only 50.9% of the frame carries data -- the rest is ocean around the island -- so a whole-frame statistic is meaningless. One name to distrust: layers on this portal are not reliably named. A sibling service is called __GW_productivity_5km_conditional_output while serving a 93 m grid. The grid declared above was read from the files, not their titles.

Provenance

Rebuilt from IWMI Africa GeoPortal ArcGIS image services, which serve no downloadable raster: they answer exportImage with HTTP 400 because their capabilities are Image,TilesOnly. The full-resolution grid was recovered by fetching every LERC tile at the pyramid level matching the service's own native resolution, decoding, and mosaicking. Each GeoTIFF carries the originating service in its source tag, and that service -- not this copy -- is the authority for its values.

The same product is indexed in IWMI's Open Data Cube, which is the route to its footprint, time extent and band metadata as STAC:

https://explorer-production-0070.up.railway.app/stac/collections/madagascar_seasonal_water_accounting

Citation

International Water Management Institute (IWMI), Madagascar Seasonal Water Accounting. Published via the IWMI Open Data Cube. Licence CC-BY-4.0.

@misc{iwmi_madagascar_seasonal_water_accounting,
  title        = {Madagascar Seasonal Water Accounting},
  author       = {International Water Management Institute},
  howpublished = {Hugging Face Hub, IWMIHQ/madagascar_seasonal_water_accounting},
  note         = {Derived from IWMI Africa GeoPortal services; see Provenance},
  year         = {2026}
}