Hello, fellow InVEST users!
I am using the NDR model to estimate nutrient retention in riparian habitat for an M.S thesis.
I am exploring the model output and trying to understand the logical connection between two outputs: the n_export.tif and the stream.tif.
I understand that the stream.tif is the stream network computed from the DEM.
In the InVEST documentation, the n_export.tif is defined as " A pixel-level map showing how much load from each pixel eventually reaches the stream."
In my n_export.tif output, the highest values of n export are the pixels that are also a part of the stream network. Photos 1 and 2 visualize how the highest n_export values match up perfectly with the stream.tif.
(photo 1: n_export map with red representing the highest n export.)
Could not upload photo 2 because I am a new user.
photo 2: stream.tif with streams in green and land with no color, overlaid on n_export)
My Question: How should I interpret the n_export.tif?
Does n_export.tif simply show the accumulation and export of N in streams?
I’m confused because I interrupted the n_export.tif to show how much load from each pixel eventually reaches the stream. I assumed that only land pixels would contribute n loads that would reach the stream so that land pixels would have the highest N export values. My sense is that n_export.tif is indeed a simple display of stream pixels that have high values of n export, but I wanted to check here for clarification.