Hi
I am trying to set up a topmodel simulation in R. The flowlength function of the topmodel package, requires the outlet coordinate of the DEM matrix, i.e. the row and column position.
Is there a practical way to get that position? I am currently using spreadsheets to get visually the position based on my knowledge of the watershed. Unfortunately, for large DEM with high resolution, it is almost imposible.
Albert Johan Mamani Larico
Yes, there are practical ways to obtain the outlet coordinate of a DEM matrix for setting up a Topmodel simulation in R. One approach is to use a GIS software, such as QGIS or ArcGIS, to extract the outlet coordinate from the DEM.
To do this, you can first delineate the watershed boundary using the DEM in the GIS software. Once the watershed boundary is delineated, you can use the "Flow Direction" and "Flow Accumulation" tools in the GIS software to identify the location of the outlet pixel or cell, which is where the flow from the entire watershed is concentrated and leaves the watershed.
The outlet pixel or cell will have the highest flow accumulation value in the watershed. You can then extract the row and column position of the outlet pixel or cell from the DEM using the GIS software.
Another approach is to use R packages that provide functions for delineating watersheds and identifying outlet coordinates, such as the "hydroTSM" package. The "findOutlet" function in the "hydroTSM" package can be used to identify the outlet coordinate based on the flow accumulation values in the DEM.
These approaches will save you time and effort compared to manually identifying the outlet coordinate using spreadsheets, especially for large DEMs with high resolutions.
Please : if you find my solution useful , recommend this reply.Thank you
To get the outlet coordinate (row and column) of a DEM matrix for Topmodel in R, you can use the following steps:
1. Load the necessary packages in R:
R
library(raster)
library(hydroTSM)
library(topmodel)
2. Read in your DEM data using the raster package:
R
dem
- Badges
- Science topic
- Similar topics
- Geoscience
- Geoinformatics
- Geographic Information System