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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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Setting boundary condition for urban catchment flow direction operation

I am trying to delineate individual catchments for a large number of kerb inlet pits from a LiDAR DEM using open source tools (QGIS, WhiteBox). In areas where the LiDAR has sampled verge elevations to ...
Eric's user avatar
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30 views

QGIS: Further subdivide sub-catchments based on DEM

I have a DEM and a vector layer with existing hydrological sub-catchments. Is there a way in QGIS to further subdivide the sub-catchments based on the DEM?
Fabi's user avatar
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QGIS - Upslope Area Function - Error

I am try to create map that shows the catchment of my reserach area. I already created the steams and related basins. Further, I would like to delete the basins that are not related with my catchment ...
Burcu Ersoy's user avatar
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63 views

QGIS Catchment Creation from existing line shapefile (streams)

I understand the general process of creating a catchment. Get DEM data Fill sinks Build stream network Create a line shapefile of the stream network Choose outlet location and obtain coordinates ...
Todd's user avatar
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1 answer
154 views

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 ...
sampeterson's user avatar
1 vote
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37 views

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 ...
he_could_be_any_of_us's user avatar
2 votes
1 answer
538 views

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 ...
rtaani's user avatar
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160 views

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'...
wainborn's user avatar
2 votes
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71 views

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 ...
Philippe Morgan's user avatar
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1 answer
303 views

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 ...
ollieover's user avatar
5 votes
1 answer
621 views

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, ...
fredrik.sundberg's user avatar
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1 answer
225 views

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 ...
W. Strabo's user avatar
1 vote
2 answers
6k views

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. ...
Sachin Shrestha's user avatar
5 votes
3 answers
509 views

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 ...
Zev_Zide's user avatar
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2 votes
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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 ...
OrCe's user avatar
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5 votes
1 answer
3k views

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 ...
Zainab Al Mansour's user avatar
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1 answer
280 views

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 ...
Craig's user avatar
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1 vote
0 answers
609 views

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 ...
Marteens's user avatar
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0 answers
234 views

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 ...
Namoat's user avatar
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1 vote
2 answers
3k views

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 ...
Colter Birk's user avatar
2 votes
2 answers
182 views

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 ...
Simon Greener's user avatar
1 vote
0 answers
27 views

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 ...
Sven Christens's user avatar
2 votes
1 answer
86 views

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 ...
Sven Christens's user avatar
0 votes
1 answer
117 views

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")....
Sven Christens's user avatar
1 vote
0 answers
896 views

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/...
Jesse Yishai's user avatar
3 votes
0 answers
4k views

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 ...
till Kadabra's user avatar
0 votes
1 answer
543 views

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 ...
Juan Ossa's user avatar
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2 votes
0 answers
72 views

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 ...
otter's user avatar
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1 vote
1 answer
257 views

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 ...
Juan Ossa's user avatar
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4 votes
1 answer
534 views

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 ...
vbj's user avatar
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2 votes
2 answers
655 views

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 *...
Basilique's user avatar
2 votes
0 answers
656 views

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 ...
Esme_'s user avatar
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1 vote
0 answers
210 views

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 ...
xmisx's user avatar
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5 votes
1 answer
136 views

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 ...
Yonnov's user avatar
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0 votes
1 answer
251 views

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 ...
MartinT's user avatar
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5 votes
0 answers
734 views

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 ...
AlwaysInTheDark's user avatar
2 votes
1 answer
77 views

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 ...
Anthony Jameson's user avatar
2 votes
1 answer
176 views

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 ...
Mining_Pickaxe's user avatar
2 votes
1 answer
1k views

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 ...
André Lourenço's user avatar
11 votes
1 answer
1k views

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, ...
anotherfred's user avatar
3 votes
2 answers
1k views

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 ...
Tatatam's user avatar
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2 votes
1 answer
308 views

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 ...
RockyTed's user avatar
1 vote
1 answer
522 views

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 ...
Afif's user avatar
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2 votes
2 answers
195 views

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 ...
Manuele Putti's user avatar
4 votes
1 answer
6k views

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 ...
Julia's user avatar
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16 votes
1 answer
18k views

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 ...
Nick Tierney's user avatar
3 votes
1 answer
4k views

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. ...
Matt's user avatar
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1 vote
0 answers
242 views

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 ...
KriKox's user avatar
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3 votes
0 answers
373 views

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 ...
blackowhite's user avatar
2 votes
0 answers
104 views

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 ...
Max2603's user avatar
  • 323