Questions tagged [catchment-area]
An area of influence defined by boundaries related to distance. In human geography, this area is defined as the location from which customers or visitors are attracted. In hydrology, this area defines the location within watershed boundaries (also known as a drainage basin).
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Create non-overlapping isochrones / service areas from points
In QGIS I have a point layer of approx. 50 points around a city that represent the on ramps to- and exits off the highway. I would like to calculate the isochrones / service areas of each individual ...
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Calculating areal distribution of soil types within catchment layer in QGIS
I have two polygons:
Layer with +100 river catchments
Soil type layer (8 different soil types)
I want to calculate the areal distribution of soil types within each river catchment. Areas should ...
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Point layer and output catchment area with different attributes
I'm using QGIS 3.22.0 Białowieża.
Using openrouteservice I identified the catchment area of new projects concerning the building of new cycling-roads.
I had a cycling road as Line-Layer (), where I ...
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Calculating population in catchment area in QGIS
In QGIS 3.22.0 (Biatowieza) by means of the "OpenRouteService" Plugin I was able to get isochrones for my point layer.
The "ORS Tools" Plugin calculates the population within the ...
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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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Have voronoi take into account line boundaries (such as rivers, highways...) (on Qgis 3.14)
I have points locating supermarkets. I would like to use the Voronoi method to automatically delineate the catchment area of each supermarket (in real life of course it overlaps a bit on each other ...
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Calculating walkable catchments from polygons [closed]
I am working in QGIS, and I would like to calculate 400 m walking catchments from a set of parks (polygons).
At the moment I have:
Parks Layer (polygon)
Urban Grid layer, which shows publicly ...
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Error with no output result while using SAGA Upslope on QGIS to determine Catchment area
I have been trying to create a catchment area using upslope area under SAGA in QGIS, and i keep getting this as an error message. i would love to know how to fix it.
The following layers were not ...
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Delineating multiple nested catchments in R whitebox; prevent primary catchment from being cut by subcatchment
I am using whitebox tools in R to delineate catchments. I have 150 lakes in a rather small area so many of the lakes are within the same catchment.
I use
wbt_watershed(d8_pntr = ptr,
...
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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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Upslope area shows an error stating tool needs graphical user interface
I tried delineating catchment area of a place. First I downloaded the DEM TIFF from internet. Then reprojected it to the required CRS. Then I used the Fill Sink tool and Strahler Order after that. ...
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Buffering with obstacles
I want to analyse parks for their reachability by foot, and I thought of doing that with a buffer around the parks (more than 300 in total). Now the problem is, that in cities usually there are ...
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A QGIS tool to perform cost surface analysis (as in ArcMap Path Distance)? not a least cost path nor a network analysis? [duplicate]
Within QGIS I am trying to perform a surface analysis to show the part of the terrain that can be reached from one or more source points in let's say 1, 2 and 3 hours of walk on the ground. That is to ...
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Calculating polygon area using 2 methods in QGIS
I am trying to calculate the polygon area using 2 different methods I saw on previous posts here.
The first method: Layer > Open attribute table > Field Calculator/Ctrl+I or right-click ...
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Splitting up polygon with grid using QGIS
I am using QGIS.
I have a county map as a single polygon, it has one FEATURE in which one FIELD is Area.
I have a grid which also a polygon that divides the county into squares and each grid square ...
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How to avoid error in "SAGA Strahler order"-process when running it on a merged terrain model file
I am trying to create a catchment in QGIS 3.8 following this tutorial: https://www.youtube.com/watch?v=2fvy9xtAHc4
However, my terrain model is originally divided into 4 overlapping tif-files. I can ...
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Catchment area raster values
In order to calculate TWI, I had to generate a catchment area raster, but I don't understand what the values of pixel represent. Any clarification?
The DEM is projeted in EPSG : 2154, so the unit is ...
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Why does running the SAGA Upslope Area tool in QGIS result in a 0 (zero) to 0 (zero) histogram and an all black layer?
I am using QGIS in order to delineate a watershed, and am using 1/3 arcsecond DEMs. I have created a Filled DEM using the SAGA Fill Sinks xxl (Wang & Liu) tool. Next I ran the SAGA Channels and ...
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PgRouting coverage area with node restrictions
I have a water network in which there exist valves at nodes between two edges (pipes). When the valve is open water can flow, if not, it can't.
How can I calculate the catchment area from a start ...
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List of international upstream areas [duplicate]
I have a list of stations in rivers. I want Earth Engine to return me a list of stations whose upstream area overlaps with at least one other country in addition to the country the station is in. This ...
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Skipping undefined elements when getting catchment area
I have a follow-up question on Population in upstream area (looping over FeatureCollection). I want to calculate the number of people living in the upstream area of stations in rivers. This code works ...
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Population in upstream area (looping over FeatureCollection)
I want to calculate the sum of the population living in the upstream area of stations using the hydro package by gena. I think I will have to loop over the stations (using the identifier "GEMS_Stati")....
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SAGA: could not initialize data objects (QGIS 3.6, Mac 10.14)
I was trying to generate a catchment area from a DEM and got the error message:
The following layers were not correctly generated.<ul><li>/var/folders/ft/rbsnpzy96r76t8rkj5fdtzc40000gn/T/...
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Watersheds and Catchment delineation in Earth Engine only with included datasets
Is there a possibility to derive Watershed boundaries or catchment areas by using one or more of the integrated data sets in google earth engine?
The available data sets are:
WWF HydroSHEDS ...
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GRASS Error: WARNING: segment zero_fill(): Unable to write (No space left on device)
I was trying to define the drainage patterns and to delineate some catchments based on a 30m DEM using
r.watershed --overwrite elev=DEM accumulation=Accum drainage=Drainage -m
but grass would ...
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How do I select rows in an attribute table of a vector layer grid which are outside of another vector layer?
So what I am working on is accessibility analysis, I want to know how many percent of the population of a country have access to certain health services within a given driving time. For example is it ...
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how can interior basins be modified in the r.watershed GRASS function?
This is a follow up question to
How does "Minimum Size of Exterior Watershed Basin" work in r.watershed command in qgis 2.18.12?
I understood that the threshold parameter is used to ...
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Hack's law for river basins
The hacks law relates the longest stream length with the catchment area of the basin. How can one construct a hack's distribution for a basin and upto what scale the sub basins have to be taken as ...
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Splitting catchments in GRASS
I have the polygon of my catchment of interest, I call it catchment A (Reyran in the schema). (format *.shp).
I have also the x-y coordinate of a dam that is situated in the catchment. I have also a *...
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Saga Catchment Area not giving expected (useful) output
I am identifying a catchment network from a DEM in QGIS3 (v3.0.3) (on a mac v10.13.4), however the step to identify the Catchment Area is not working.
I have an input DEM, with layer CRS set to ...
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Setting maximum slope/flow length in flow accumulation using SAGA?
I like to limit the slope length in SAGA GIS. In other words, the flow accumulation should only account for a specific length until a subsurface flow initiates and surface flow stops. Actually, I ...
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Delineating service catchment in QGIS?
I have a set of locations each representing a service capacity. I also have a polygonal layer with each polygon representing local demand for that service. For each location, I would like to define ...
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pgr_drivingDistance How to split edge if max distance is reached halfway through the edge (PGROUTING)
I would like to generate a catchment within a network, up to a max cost, using the pgr_drivingDistance function. This returns all the nodes within this distance - but does not provide for partial ...
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Determining areas on a Voronoi Diagram around a point
I currently have two data sets concerning the Netherlands, one containing longitudes and latitudes of population cores (Hubs) along with other information, such as average house price, and the other ...
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How can one compute the proportion of a country's area that lies within a given distance from the country's border?
A lawyer friend of mine is preparing a legal argument that concerns the border region of Germany: the part of Germany that is within a given distance (e.g., 30 km) of the country's border. He needs ...
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Catchment area map automatic creation
I want to create a map that shows the catchment area of download mirrors. What I found so far is only a manual option where you have to draw an area around that point. But I don't know exactly where ...
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Error in catchment area calculation
I downloaded a DEM based on the ASTER Global Digital Elevation Model (resolution 30 m; ASTGTM2_N42W009_dem.tif) from the Earth Explorer website (https://earthexplorer.usgs.gov/). I am trying to ...
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Voronoi that don't cross boundaries
I have several dozen points plotted across the UK. Each point represents a facility that serves local people. To estimate the catchment areas of each facility I created Voronoi polygons around them, ...
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QGIS: Saga Channel network: how to prepare SRTM data
I am trying to use the Saga toolbox (2.2.3) in QGIS (2.18) to create a channel network from SRTM data using this tutorial 1.
It works, but the result I get when using the DEM that comes with the ...
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GRASS r.basin resolution error at strahler stage
I built a composite DEM of Florida using USGS NED 1 30m DEM tiles. I used r.patch to convert the individual tiles into a single raster and then projected it into a new region with the EPSG:26958 ...
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Combining several catchment areas
I would like to combine several catchment areas (points feature) into one catchment area. There are examples of my catchment areas.
Each area has one source (POI).I will use the combined area to ...
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How to create a buffer for catchment area of an historical settlement
I'm looking for a way to create a buffer from a specific point that represents the catchment area in a selected time in QGIS. I've found many tools that allow me to do it using driving time or public ...
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Network analysis using QGIS?
I'm working on my bachelor thesis right now and I want to find a catchment area for different bus stops. Is there a function in QGIS where I could use a point layer as input, use ways as distances and ...
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Create a circle of defined radius around a point and then find the overlapping area on a shapefile
My use case is related to calculating the area of a polygon in a shapefile that is covered by another polygon.
Specifically, I want to do the following:
Create circles that have a 100m radius, from ...
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How to calculate areas of land cover from a File System Raster?
I am using ArcMap 10.2. I have a raster displaying land cover. I also have a shapefile of polygons overlaid on top. I would like to calculate the areas of different land covers within the polygons.
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Calculating weighted catchment area
I would like to calculate the catchment areas of several points in a polygon. It means, I have a city, some POIs in the city and a lot of districts (the centroids). The POIs have different weighting ...
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GRASS v.net.iso does not include all lines
I want to define catchment area for bus stops in small city. As a result of v.net.iso in QGIS with GRASS I don't get all highways in that city. Here are my steps:
importing above layers into GRASS ...
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Comparing areas of two raster files [closed]
I need to compare the areas of two rasters for calculating the percentage parts from another.
For example, I have one raster file which shows separated agriculture fields. The value of each field is 1 ...
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Multiple watershed delination with QGIS [duplicate]
I am trying to divide a DTM model in subbasins but I have set specific outlet points for the subbasins, and not to use a thershold.
Is there a tool similar to r.water.outlet but with multiple outlet ...
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Can 2 GIS layers which representing the same area be compared directly while having the same datum but different coordinate system?
My question is about how coordinate systems affect comparison of different layers - I have tried to refresh my memory about coordinate systems in GIS, but am still unsure about this situation.
I am ...
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