National Hydrography Network Dataset Tools for R
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README.md

hydrolinks R Package

Hydrologic Network Linking Data and Tools for R

Build Status | CRAN_Status_Badge

Bug reports and feedback

First things first, if you are having an issue, please consider reporting bugs and submitting feedback via the Github Issues page.

Package Description

This package provides tools for linking latitude and longitude (geopoint) data with hydrologic networks, such as the U.S. Geologic Survey's National Hydrologic Dataset (NHD) or they global hydroLakes dataset. The function automates the access and download of these large, cumbersome datasets and provides a number of techniques for geographic data to the hydro networks.

The key functionality hydrolinks provides centers on three areas.

  1. Linking geopoint data (lat/lon) to mapped lakes, streams and rivers. This provides an unambigous ID-based link to mapped aquatic features.

  2. Providing on-demand access to mapped aquatic features based on ID.

  3. Enable traversal of the hydrologic network with full support for both lakes and streams.

hydrolinks is available on CRAN. Please install from there.

Example Usage

Link to a waterbody feature

Lets say we have an observation lakeobs1 that was taken at some point. We want to see if there is a lake at that point, and get the information, including ID, of that lake.

Lo and behold, this point is over top of Lake Tahoe. We can get further information about this lake from the mapping layer we used to link. National Hydrography Dataset Highres (NHDH) has some other useful information included.

##   PERMANENT_      FDATE RESOLUTION  GNIS_ID  GNIS_NAME AREASQKM ELEVATION
## 1   44560536 2012-03-12          2 01654975 Lake Tahoe 498.1268      6229
##        REACHCODE FTYPE FCODE SHAPE_LENG SHAPE_AREA VISIBILITY centroid_x
## 1 16050101000339   390 39009   1.624393 0.05186653          0   -2037514
##   centroid_y MATCH_ID
## 1    2044681 lakeobs1

Now, lets generate map of the linked lake (Lake Tahoe). Using hydrolinks, we don't need to dig through shapefiles. We can just use the ID we got from linking.

library(sf)
lake_poly = get_shape_by_id(linked_wb$PERMANENT_, dataset = 'nhdh', feature_type = 'waterbody')
#Simple quick viz of polygon
plot(st_geometry(lake_poly), main='Lake Tahoe', col='Dodgerblue')

The polygon returned is fully functional, so it could be used for quantiative analysis of the lake shape or location. We use the sf package throughout for spatial data handling.

Network functionality

The latest and greatest feature allows for the traversal of the hydrologic network. Buildling on what we did above, we can quickly grab very useful information from the hydrologic network.

For example, lets grab and plot all inflows into Lake Tahoe. We will start from the lake and traverse up the hydrologic network. We will specify a max traversal distance of 50km to prevent the traversal from exploding (can happen with unlimited bounds going up the network, e.g., Mississippi).

upstream = traverse_flowlines(50, linked_wb$PERMANENT_, direction = 'in')
upstream_shp = get_shape_by_id(upstream$PERMANENT_, dataset = 'nhdh', feature_type = 'flowline')
plot(st_geometry(upstream_shp), col='palegreen')
plot(st_geometry(lake_poly), main='Lake Tahoe', col='Dodgerblue', add=TRUE)

Boom! We have Tahoe and all its input tributaries. Again, the shape data returned are the same as from the underlying hydrologic network datasets, so they can be used in spatial and other analyses.