Questions tagged [flow]
The direction and/or volume of something moving across a surface or within a network. Note this tag is primarily for data or function related questions as opposed to cartographic representation.
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Measure flowpath length from a point
I am using QGIS 3.28.2-Firenze. I have am using WBT "tracedownslopeflowpaths" to establish flowpath from a 3D scalar point (numbered points in image). How do I set a measured distance (1320 ...
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Measure Flowpath Direction and Length from a Point
Using QGIS 3.28.2-Firenze. I created a depressionless DEM, created a shapefile with points I want to measure flow from by using "Add Point Feature", ran D8 Flow Pointer, and then ran ...
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Flow path from a point
Are there any tools in the QGIS Processing Toolbox that allow calculation of flow path and distance from a point on a roadway?
I have made a depressionless DEM (geotiff).
I'm analyzing runoff from a ...
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Tool for modelling uniform groundwater flow from points and isopotential lines (elevation contours) - QGIS
I am going to investigate where a specific particle in a groundwater system will be found in 10 years.
I have the following data:
A vector point layer with x and y coordinates of points I want to ...
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Adjusting flow direction of river based on DEM in QGIS
I have a huge vector layer as a line, that represents the river. The problem is that the flow direction is sometimes wrong (goes uphill). But I can't correct that manually, cause the layer is too big.
...
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Find polyline end vertex on polyline edge
I am looking for a basic or best approach to find any polyline End-vertex that falls on the polyline Edge. I have a set of polyline data that shows the flow of electricity based on the Start and End ...
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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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Align arrow (point layer) to water direction (line feature)
Assuming that pipes are digitizet correctly (first node as upstream, last as downstream), I need to align the arrows of a point layer to display flowmeter's direction. So far I need to use v.split (...
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Arrow head at the last path segment of Bezier curve
I am making a flow map. For most flows, I used the curved arrow symbology associated with lines.
For my Mediterranean flow, I have to draw a path that ends with an arrow.
I use the Bezier plugin to ...
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Manually adding centroids to arrows in Virtual Layers in QGIS
Currently, I'm making a map that depicts the migration flows of people who have finished their university degrees and decide to move to a different Dutch city after their studies. By following Anita ...
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r.terraflow fails after using fill-sinks
I'm using QGIS 3.10.11 with GRASS 7.8.4, and the default SAGA version that's included with the QGIS standalone 3.10.11 installer from QGIS.com.
I'm having an issue where r.terraflow fails after using ...
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Data flow documentation tool
I am in the process of mapping the journey of our data through the different apps used by our service. We use an ArcSDE geodatabase as main data source.
This data is
viewed in ArcMap
edited with ...
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Adding arrows to hydro line to show direction that river is flowing using ArcGIS Pro
I have a large number of rivers and streams on my map which do contain elevation data in the attribute table. I would like the lines on the map representing the rivers to have small reverse arrows ...
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Identify false outlets on a river network
I have a river network that is very poorly defined (lots of gaps). I need to identify all the false outlets. The picture below provides an example of one of these false outlets. The image shows ...
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Flow accumulation on grid in R
I would like to calculate the number of cells from gridded elevation data that drain into a particular cell. First, I calculate the flow direction by selecting the cell with the steepest slope from ...
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Generating slightly curved arrows in QGIS 3
In Geometry Generator in Symbology in Layer Properties, the following expression works, but the result is not satisfactory due to the middle point fixed coefficient 1,1:
make_line (
start_point(...
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Flow data distribution within features of overlapping layers
I want to improve/adjust/comprehend the formula (see below) that was used in my previous question: Transferring flows (connections + values) between polygons for calculating flow values of mobile data ...
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Flow Distance Not Calculating for Entire Raster
I am trying to calculate the height above the nearest stream for an area. The problem is, it only does so for a portion ( the colored area below) of my area of interest. In the pic below, the black ...
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Listing grid cell numbers for outlet according to flow direction using ArcGIS Desktop?
I am trying to list grid cell numbers whose flows contribute to the red cell I draw in the figure according to the known flow directions. Directions and colors are shown in the figure.
What tool can ...
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Transferring flows (connections and values) between polygons in QGIS
In QGIS there are two shapefiles representing the moving data between cells and one additional layer, see image below
Moving data defined by:
A polygon 'LayerA' (transparent squares with red outline)...
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Getting angle of point generated from DEM in Raster using Field Calculator in ArcGIS Desktop?
I am trying to calculate the angle of some specific points generated from flow direction in ArcMap 10.2. I converted the DEM to flow direction and then to points. I am trying to convert the grid_code ...
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Generating flow path using r.drain from rgrass
I need to generate the flow path using r.drain from the rgrass7 package in RStudio.
I am new to GRASS GIS and prefer to use the R package instead. I want to generate a flow path from a grid cell.
...
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How to extract a flow chart from points connected with lines?
I have some points connected with arrows, like the following example:
How can I extract a flow chart like the following?
I tried to use the flowMapper plugin but it seems it is not what I want.
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Showing overland flow route on DEM in QGIS?
I've been asked to produce a risk map at work which will show the possible flood route from sewers that surcharge (flood) during heavy rainfall. This is basically where I know the x-y coordinate (OS ...
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Why TauDEM specialized tools (e.g. D-Infinity Distance Down) are only available with D-Infinity flow model?
I would like to know why most TauDEM specialized tools have been developed just for the D-Infinity flow model.
Is it because the D8 would not make sense for these algorithms, or they just have not ...
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Displaying flow direction raster in QGIS?
I have a raster with flow directions (geotiff). In ArcGIS I can use the vector field symbology option to display nifty arrows (see image). Is there a way to accomplish something similar in QGIS? I've ...
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Longest flow path in QGIS from single feature vector
I have got a vector layer with one feature (MultiLineString) representing a river network (s. below) without bifurcations. In addition there is a point shapefile containing the outlets of different ...
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348
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r.flow in QGIS 2.16.1 generates wrong output
I try to run the r.flow module to get the flow path length of my layer out.
The input Layer is a DEM with pixelsize 0.0083 and the selected CRS (EPSG:32646, WGS 84/ UTM zone 46).
First of all I ...
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Determining flow path length in QGIS?
I need help with qgis flow path length.
I try to run the program and when I run the program I get a raster with 0 values, as input I'm using filled raster, I don't now if I'm doing something wrong or ...
user107192
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Edit RGB values of 0,0,0
I am VERY new to ArcMap and GIS in general.
I converted some lidar data to a GEOTIFF, using a program called CARIS (it was an .csar file) and imported this into ArcMap. There are some areas that are ...
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Interpolation of river pollution data
I have 6 samples of water quality parameters taken on a 10 km stretch downstream (Cooum River in Chennai), so it's basically the estuary.
The river discharge and flow is extremely low, therefore I ...
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How to display Flow Direction arrows + Burn Stream Netwok in QGIS?
I have used the automated r.watershed tool in QGIS 2.18 (GRASS plugin) to conduct a watershed analysis (basin boundaries, flow direction, flow accumulation etc).
I'm stuck on the following operations:...
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Flow Path length
I'm a student and pretty much new to QGIS, GRASS and SAGA tools.
I'm trying to calculate the longest flow path length using SAGA "flow path length" module in Qgis. Using the default parameters:
I'...
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Use of the Peclet number in FEFlow as a mesh-quality metric
The user manual for FEFlow (v7.0) states
"In transport models, the elemental distribution Péclet Number is
available which can be used to check whether the spatial
discretization is ...
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468
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QGIS Multi-Basin Delineation (Pour-Point) Hydrology
I'm working on a QGIS plugin and struggling to find some existing QGIS processing functionally I could leverage. I need to replicate multi-basin delineation using pre-defined pour points. Specifically,...
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Summing values of grid moving upstream along flow paths in GRASS
I would like to sum the values of a grid, moving upstream along flow paths. In other words, I have a grid A with a value for each cell. I need to build a new grid, B, in which the value of each cell ...
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Show flow direction for pipes as arrows in QGIS [duplicate]
I have a vector layer (line features) which consists of different pipes. In the attribute data I have fields that indicate the upstream elevation and downstream elevation values.
I am trying to ...
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Making lines curvy in QGIS
In QGIS I am working on a map with lines connecting locations created with the MMQGIS plugin. Is there an easy way to make those direct lines somewhat curvy for aesthetic purposes?
I'm trying to ...
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Incorrect length from Flow Length tool
Why is my flow length tool giving value less than one? Isn't a flow length tool supposed to give the maximum length of upstream flow to the cell? Then, how come?
I am using coordinate system of GCS ...
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Understanding hydrology and DEM results?
In first picture, you can see an image of a lake(Bellandur lake, bengaluru, india). In second picture, you can see the flow accumulation data for the same area I made(after "fill"ing the sinks). As ...
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Finding vectors with wrong direction in river network
I have a shapefile containing network of rivers for the whole country. The description of the layer is saying that orientation of the vector should be the same as the river flow. This is true for most ...
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Fast, simple assignment of flow directions to flats in GRASS
I have some enormously huge DEMs which I'd like to assign flow directions to. These DEMs are guaranteed to have no sinks, just flat areas.
It seems as though the only ways of assign flow directions ...
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Map library supporting linestring curve rendering to produce flow map
Is there some function/plugin for any javascript map library (OL, leaflet, ArcGIS API for JS) to render WFS or Geojson LineStrings not as simple line but as curves?
I want to make mobility flow maps ...
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SAGA GIS Channel network crash
So, I had this very weird bug while treating my dem data lately. I used SAGA to create flows channel networks on a dem that I acquired a little while ago. Preprocessed it using sink route detection ...
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Create curve/arc between 2 points
I am trying to create some visualisations using bus journey data. I am looking to plot journeys along one long road, showing passenge journeys. The principle is the same as a radial flow map for ...
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Identifying flow of a Wastewater Network
I am trying to identify the flow path of a wastewater system.
I am using Arcgis 10.3 and I have set up a geometric network system and identified the sources and the sink (sources = blue dots, sink = ...
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Color gradient to show direction in polygons (filling, color ramp, gradients)
My data is 2 point-layers: 1 layer origins and 1 layer destinations. I connected these pairs of origins and destinations: firts with lines. As I know that in qgis, there is still no gradient fill for ...
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Calculating flowpath length to stream within catchment using ArcGIS Desktop?
ArcGIS 10.3 provides a hydrology tool "flow length" which calculates the length of flow paths within a basin to the outlet of the basin. I am trying to calculate flow path length and flow path ...
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Looking for data on river flow speeds
I'm looking for sources containing data on measured river flow speeds, any / all locations worldwide, in any format or language.
Googling didn't help much.
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Why does the flow direction tool in ArcGIS desktop give wrong output (unique values from 1-255)?
I ran the flow direction in ArcGIS, and received unique values ranging from 1-255. I know that these values are wrong, and should be along the lines of 1, 2, 4, 8, 16, etc multiples. The DEM is ...
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