knitr::opts_chunk$set(echo = TRUE, out.width = "100%", message = TRUE) library(sf); library(mapview)
The first question generally raised is, "what is a hydrofabric?" To date, the term has been been used to describe artifacts as narrow as a set of cartographic lines, all the way to the entire spatial data architecture needed to map and model the flow of water and flood extents. For our purposes here, the hydrofabric is the base data that allows NextGen to run. It provides:
The hydrofabric also establishes a system of linked data and Web infrastructure that can relate to, and extract from, linked sources like:
knitr::include_graphics('../man/figures/what-is-a-hydrofabric.png')
Discritizing the land surface into computational elements is fundamental to all modeling tasks. Without it, distributed and lumped models have no way to apply the needed model formulations or computer science applications to achieve meaningful results. Therefore anyone who cares about the science and application of water resource modeling should care about the underlying data as it drives the locations where forecasts are made, the attributes that inform a model, and the spatial elements in which formulation are valid.
However, describing the earths surface - particularly at continental scales - is a tricky task. Automated techniques can get us a long way in representation, however the modeling task at hand and local knowledge should be used in developing an authoritative product. Through time, local knowledge has been collected in a number of places, but never centralized. Further, one off products (like the NHDPlus) have been used to guide all modeling task even in cases when its resolution, or representation is not well suited.
The aim of NOAAs work in this space is to develop a federal reference fabric to support all flavors of modeling, and a national instance of that reference fabric to support heterogeneous model application.
Equally important is the software tools to support flexibility and community uptake; the data models to support interoperability, community engagement, and long term stability; and a reference data set with the quality assurances that when one uses the product they are getting a well vetted resource that will be able to play nicely with the growing Ngen framework.
The most up to date NextGen hydrofabric and resources can be accessed from the public facing Lynker Spatial account.
In practice we strive to develop these products to take advantage of the following:
knitr::include_graphics('../man/figures/hyfeature.png')
The OGC Engineering Report "Hydrologic Modeling and River Corridor Applications of HY_Features Concepts"
The Network Linked Data Index (NLDI) here, and here and here
The lynker-spatial [hydrolocation inventory]
knitr::include_graphics('../man/figures/ogc_sfs.png')
Extracting subsets from the primary hydrofabric data product does not require code, however, if you are eager to build, modify and expand on the existing products the
remotes::install_github("NOAA-OWP/hydrofabric")
Hydrofabric provides a easy install for a variety of hydroscience, data science, and spatial libraries that are needed.
Attaching this library, similar to the tidyverse
, installs and loads a set of software designed to manipulate, modify, describe, process, and quantify hydrologic networks and land surface attributes:
library(hydrofabric)
library(hydrofabric)
will load the core packages (alphabetical):
Additionally it will load key geospatial data science libraries:
dplyr
(data.frames)sf
(vector)terra
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