Questions tagged [watershed]
Use this tag when asking a question about a watershed related to GIS environment.
230
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Finding watershed area to polygon area using QGIS [closed]
I am new to using QGIS. I mostly use CAD at work. I am trying to find a way to delineate a watershed area for a large trench. So I am basically trying to make a long hole in a DEM and have GIS ...
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QGIS - The channel network and drainage basins are missing at the shoreline
I am new to QGIS, so I hope I have included enough information.
My aim is to be able to determine, how much freshwater runs into the sea and where it enters the sea.
I start with the original DEM file,...
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33
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How to calculate watershed associated with a polygon using a DEM
I have found instructions that outline how to determine the watershed uphill of a selected point using a DEM in QGIS (https://youtu.be/CE7zZCkFbg4).
I am starting with a polygon representing property ...
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Applying D8 ( or other watershed algorithm) on urban areas with some artificial constraints
Referring to the post here on the limitation of D8 algorithm, or watershed algorithm in general.
From the post I have the impression that even though the urban areas have a lot of flat surfaces ( ...
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28
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Polygons sharing a vertex causes gaps in topology
I have created a floodplain with raster to polygon, smoothing/simplifying, dissolving, and repairing geometry after every geoprocess.
Now I'm doing a topology check for must not have gaps and it has ...
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36
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Large polygon with null geometry
I have a flood hazard area polygon that I'm creating based on a depth raster for a HUC 8 watershed. The script tool I use is as follows:
import arcpy, os
arcpy.env.overwriteOutput = True
arcpy.env....
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2
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1
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80
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Continental divide between rivers Danube and Rhine in Germany (watershed vector data) in Google Earth
Is there a line available for Google Earth that is showing the continental divide between the Rhine river and the Danube river? For me, it would be crucial to see where the rainwater is going to go.
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250
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How to resolve the watershed delineation failure in QGIS due to NO DATA values in 'Flow Direction File'?
How can I resolve the issue of getting errors while delineating a watershed in QGIS? I have tried using different DEMs (ALOS and Cartosat), but I am consistently encountering NO DATA values in the ...
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Urban watershed delineation for flash flood events
I am currently trying to create urban watersheds using the ending points of flash flood events (in the NOAA Storm Events Database) as outlet points for a city. While doing so, the watershed that is ...
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How to divide watersheds by iscochrones/travel times in QGIS?
I need to divide my watershed by isochrones of equal travel time to the output, dividing my watershed to inter-isochronal areas in order to use the time-area method to calculate runoff time series, in ...
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How to use Watershed tool in ArcPy
I have 40 pour points and want to find out the area upstream of each pour point. I see that I can use the 'Watershed' tool for this. However, I do not want to do this manually. Therefore, I am trying ...
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How to burn a sewer network into a DEM
As part of the sewershed delineation using the ArcHydro toolbox in ArcGIS Pro, I need to burn my sewer network into the DEM to recondition it based on pipe elevations. I have calculated and added the ...
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153
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Unable to run SAGA-Terrain Analysis-Fill sinks (wang&liu)
I am trying to do a Watershed analysis using QGIS. However if I want to run the SAGA function Fill sinks (Wang & Liu) I get an error that the 3 files were not created (full error down below). I ...
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Detect sharp changes in elevation
I've been scouring the forums to see if there is a way to detect sharp, unnatural elevation changes greater than a certain amount in ArcGIS Pro. I've run across an issue in some DEMs where there are ...
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Implementing seeded watershed algorithm in R
I am trying to implement seeded watershed algorithm in R. I want to use the seed generated by local maxima filter. I am using watershed from lidr package but I get an error that says seed is not a ...
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233
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Watershed segmentation in QGIS without SAGA
I have a model in the QGIS model builder that extracts illustrative tree canopies from LiDAR. The model works really well but relies on the boundaries of watersheds from the Watershed segmentation ...
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Looking for an automated method for headwater watershed delineation at county scale
I am hoping to delineate watersheds, which are extremely small, across a large area.
My objective is to create a workflow that will delineate all head water catchments through an automated process. I ...
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Qgis Generate basin polygons from valley linestrings
Starting from these two data sources, FIGURE 1
Openstreetmap: I have a set of linestrings they represent
(these data I have extracted from openstreetmap filtering with the tag natural = valley) ...
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285
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Calculate intersect area for every feature in layer (ArcGIS Pro)
I have a .shp with multiple watersheds. I have a .shp with all the wetlands in the watersheds. I want to know for each watershed the area occupied by wetlands. So for watershed #1 there's Xkm2 of ...
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60
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Remove inner boundaries in merged vector layers
I am using QGIS and the GRASS plugin for a watershed analysis where I would like to merge three small natural catchments into a larger one.
I used the 'Merge Vector Layers' function (under the 'Vector'...
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174
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Water Pipeline analysis in PostGIS like Pipe Burst analysis, valves ON/OFF affected areas etc
I have made a network of Water Pipelines with valves of my town, now I want to carry out certain analyses like
Pipeline Burst analysis to identify the least number of valves that needed to be turned ...
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433
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How to measure length of Sub-watersheds / Sub-Basins in ArcGIS Pro?
I am looking for guidance about reliable method of sub-basin length calculation.
I am a student and working on morphometric analysis for prioritization of sub-watersheds of a river basin. I am using ...
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Watershed analysis for construction site
Watershed analysis pretty straight forward except I lose understanding when it comes to selecting the pour point at a point along a stream.
What if I have a construction site, what is my pour point?
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148
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How to resolve the problem of multiple parallel streams and unmatched river flow in Stream Network?
I am working on sub-watersheds delineation of an area. The extracted streams do not match with the real world scenario. I have two issues;
there are multiple streams lines which do not match with ...
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219
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What does SAGA's flow connectivity show?
In the 'Channel network and drainage basins' algorithm from SAGA in QGIS, a couple of maps are generated. I can't seem to find any documentation on the different output maps. Am I missing something?
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2
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407
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Finding longest flow path in multiple basins at once using ArcGIS Pro and Spatial Analyst
In my watershed I have around 400 basins. I need to find the max flow length in each basin. The "Flow Length" tool creates the flow length for the entire watershed, not for each individual ...
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103
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Watershed tool in for loop on single feature point shapefiles creates empty rasters in ArcPy
I am using ArcMap 10.8.
I have a flow direction raster and many point shapefiles with one feature each.
I want to calculate one raster watershed for each point shapefile
fd = "C:/sample/raster/...
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177
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Hydrological catchment area for a road segment (QGIS)
I try to calculate the hydrological catchment areas for road segments in a mountainous region in QGIS. As far as I see, I can only calculate watersheds in general or for particular points. Is there a ...
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540
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Basin code in Google Earth Engine
How to find 6digit in HYBAS_ID of "WWF HydroSHEDS Basins Level 7" database.
Technical Documentation says that:
Next 6 digits represent a unique identifier within the HydroSHEDS network; ...
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196
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Problem with r.fill.dir on merged raster layer
I am going to use r.fill.dir on an area. The downloaded data comes as a set of tiles that puzzle together.
In order to delineate watershed across tiles I need to merge them to a complete raster.
...
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282
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Displaying in QGIS a TIFF product exported from GEE
I am new in GEE and am attempting to export and use a tiff product (WWF HydroSHEDS Basins Level 9) from GEE (output image, details, and code are shown below). The problem comes when importing and ...
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Distance to a polygon along the stream flow path
I'm using Arc Hydro Tool for watershed processing and management.
I'm in a stage where I need to calculate the distance of all cells in a raster (the study area) to some polygons along the flow path.
...
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I want to use create legislative district polygons based on watersheds using QGIS, preferably
Generically, the problem is to take small polygons (HUC 12 watersheds intersected with counties and/or minor civil divisions) and disolve those into larger polygons that meet a couple of criteria:
...
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760
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Using Watershed Basin from SAGA in QGIS
I have a weird phenomenon going on in QGIS.
I want to derive a channel network and also the catchment areas using "watershed basin" from SAGA. In the end I want to have the flow direction ...
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452
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Water spread using SAR images (Sentinel-1) in Google earth Engine. Converting into Vector
I am running a water spread mask of Karnataka, India using SAR imagery (sentinel-1). I want the water classified pixels to be in vector (shapefile) to export them to google drive.. As I am new to ...
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Selecting area upstream in watershed tool of ArcMap
How do I calculate the watershed at several locations using the watershed tool of ArcMap?
When I am doing it, I get the watershed cut at all the points, and not all the watershed upstream. I set the ...
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How to isolate cooling influence of green roofs from land surface temperature data? [closed]
The idea in summary is to use land surface temperature (LST) data as a means to draw cooling extents around green roofs, as if you were drawing watershed basins around a lake, where high temperature ...
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112
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Flow Direction flowing opposite to actual direction
I am using ArcMap 10.7.1.
I am trying to delineate multiple urban watersheds in GIS for the City of Denver (sometimes called sewersheds) using Spatial Analyst. I am looking at several drainage points ...
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Breaking up existing watershed polygons by flow to individual tributaries
I have an existing hydroshed dataset (HydroBASIN lev12 basins from the HydroSHED dataset) that I would like to split up further, so that each tributary has its own basin delineated (see below).
I ...
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56
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Calculating the greatest length of a polygon using QGIS [duplicate]
I'm new to QGIS and I need to know the easiest way to calculate the greatest length of a polygon. I already know the "rule" tool but I want to do it automatically because I have a huge ...
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188
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Selecting the transect lines which touches the divide of a polygon from the river line
I have a polygon and transect lines which passes inside the polygon.
Here I want to select the lines which touch the drainage and divide. The transect lines split at the river intersection.
Since ...
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446
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Exporting same attribute values to separate layers and merging them in QGIS
I am trying to split watersheds of the same attribute table into separate layers.
The Two two repeated values, for eg. SW1 and SW1 both are splits from a same watershed called 'SW1'. I am trying to ...
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ArcGIS tool which shows all cells a point flows into?
Is there a tool that is effectively the inverse of flow accumulation of a pour point - as in, if I have a specific point that is the site of potential pollution, is there a tool which will show all ...
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593
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Error while doing Watershed analysis using Python
I am trying to do watershed analysis using Python in jupyter notebook. Whenever I am passing commands regarding watershed delineation in Python I am getting output as raster matrix and when I am ...
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92
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Finding a pour point in a polygon?
I have a polygon shapefile (created by someone else) that is a bunch of little watersheds. Unfortunately, it doesn't include any coordinates in the attribute table for the lat/long of the pour point ...
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119
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Determining if species point data is upstream or downstream of artificial fish passes using ArcGIS Pro
I am working with ArcGIS Pro.
I am working on a project to determine how to prioritize restoration of artificial fish passes. I have been supplied with species point data, point data of the artificial ...
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195
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GRASS GIS change raster output size?
I have a large inut raster geotiff map of size 12000x9000.
I am running r.watershed to output a stream raster map. However it is much lower resolution, only about 960x711.
How do I make GRASS GIS / r....
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Why no need for "fill-sinks" when using r.watershed in GRASS QGIS?
I've seen a few places that when using the r.watershed function in GRASS QGIS, you do not need to use the "fill-sinks" procedure on the DEM before running the function.
According to the ...
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TauDEM: Missing cell area contribution
I have a terrain, that looks like the below:
The geotiff file can be found here
I run the geotiff file with the taudem, with the threshold value =10
1. PitRemove.exe Site6.tif
2. D8FlowDir.exe -p ...
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How to train or calibrate stream flow accumulation using observation data?
I need to calculate flowrate at designated coordinates (Point of interest - POI) in a watershed. I have real-world data from stream gauge stations along this watershed for each 50-150 km2 rainfall ...
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