Hydrofabric
Water
Operational
Describing the hydrofabric as a dataset.
Back to Data Sources
Hydrogaphy
A term that technically translates to study of water, this is most commonly found in the context of the applied science of measurements of the ocean floor but is often conflated with the study and representation of the flow of water over the earths surface and its’ representation. When you encounter someone talking about hydrography, they likely actually mean…
Hydrofabric
The most technically appropriate term for the conceptual standard as defined by the OGC1. As a concept though, I like to think of “hydrofabric” as the critical differentiator that separates planetary hydrology from earth hydrology. In planetary hydrology, we know nothing about the system that we are trying to model beyond coarse remote measurements, a high quality DEM if we’re lucky. On earth however, we have the advantage of long durations of meaningful measurements and an implied understanding of the system beyond what “just physics” might tell us, so when we try to model our system, it’s useful to know critical areas that we want to represent, the standard flow paths and channels that usually flow, and how basins delineate themselves. The hydrofabric product does this for us. As I like to say, particularly at the national scale, “water flows down channel, not water flows downhill”.
Quick links: Links to the official documentation, publication: (OGC® WaterML 2, n.d.), more information and the data bucket
3D Hydrofabric
If hydrofabric is the line/polygon representation of the hydrography of a system, 3D Hydrography is intended to walk all the way back to a point cloud. This is a long running program that is still finding it’s footing, and is still an active area for community to debate and come to a concensus. Our take is here: [[20241016192617]] Hydrofabric3D Data Model
References
Writing layers out into gpkg from a cloud store: [[20240831204113]] Hydrofabric manipulations
Explainers
[[20241014200956]] What does incorrectly labeling a catchment mean physically?
Issues
https://code.usgs.gov/wma/nhgf/reference-hydrofabric/-/issues/152 https://code.usgs.gov/wma/nhgf/reference-hydrofabric/-/issues/150 https://code.usgs.gov/wma/nhgf/reference-hydrofabric/-/issues/143
Hydrofabric as datasets
Because everything is done in table space as opposed to geographic space, the operations tend to be lightning fast and more memory efficient and so you are able to scale your analysis much faster than you otherwise could on the same hardware, same timeframe, and therefore same cost. This enables applications like CONUS scale flood mapping, USGS water prediction, and associated hydrofabric operations to be executed on common hardware.
References
OGC® WaterML 2: Part 3 - Surface Hydrology Features (HY_Features) - Conceptual Model. n.d. Https://docs.ogc.org/is/14-111r6/14-111r6.html.
Footnotes
see my Hydrofabric data model page↩︎