Creating a MERIT river graph from provided data

Info

This page documentst the create_edges() function

Discretization of MERIT flowlines

Given the provided MERIT flowline data, you will notice that there is no standard size/length of these flowlines. Some of the catchments are large (50+ km reaches) others are much smaller (0.5 km reaches).

To get around this, we break up the MERIT river connectivity into smaller pieces based 2 km segments with a 666 m buffer.

This data processing is done with dask/zarr for optimal speed and chunked data storage (fast read/writes).

What is being saved to zarr stores

The following data is being saved:

Attribute	Description	Data Type	Example
id	The edge id	str	7402309_1
merit_basin	The edge's merit basin	int	7402309
segment_sorting_index	An ordering index for the edge (Drainage Area)	int	2
order	Edge stream order	int	1
len	Edge stream length	float	2000.0
len_dir	Edge stream Euclidean Length	float	2000.0
ds	Downstream connection	str	7402309_2
up	Upstream connection	list[str]	7402308_2
up_merit	Upstream merit basin	list[int]	7402308
slope	Edge stream slope	float	0.002
sinuosity	Edge stream sinuosity	float	i
stream_drop	Difference in elevation over the edge length	float	i
uparea	Upstream drainage area	float	283.29
coords	Edge map coordinates	str	i
crs	Edge map projection	CRS object	i