Questions tagged [flow-direction]
In hydrological modelling, flow direction shows the side the flow goes towards. Flow direction is used in spatial analysis to generate a drainage network by generating flow accumulation.
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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 ...
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New flow direction attribute for sub-catchment layer in QGIS
I have a polygon layer in QGIS with self-created sub-catchments. I also have a DEM, a flow-direction raster and a raster with the corresponding stream network and stream order. I would like to create ...
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Channel network from DEM of a river has unusual linear lines
So I needed to obtain channel network, basins, flow direction, etc. I downloaded aster_DEM from usgs, clipped it to an extent, warped it to UTM projection, then filled the sinks using Wang and Liu ...
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QGIS: determining the ice divide on a small ice cap
I have a GeoTIFF file with the surface elevation of a small ice cap. The ice cap has an ice divide, where the ice diverges. Part of it flows towards a glacier in the north, the other part flows ...
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Running grass7:r.watershed in QGIS gives different results to running identical process in QGIS
a former colleague created a QGIS tool in Python for the Team which creates Flow Routes and TWI (Topographic Wetness Indicator) maps for a selected location.
I have run through the code and copied the ...
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How to set up r.watersheds if it generates too short streams on river valley sections that are too wide
Related to this question too
I am delineating a very big watershed with very wide river valley.
When I tried to perform with PCRaster, the directions map wasn't generated properly, as sticks upon ...
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Exporting ldd raster from grass to PCRaster fails
I successfully exported Float32 SCALAR data with
r.out.gdal input=$file output=$file.map format=PCRaster type=Float32 createopt="PCRASTER_VALUESCALE=VS_SCALAR"
but for ldd data (previously ...
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How to measure the distance between two points in the same layer accounting for stream meandering in ArcGIS Pro
I am trying to measure the distance (in meters) between points that are in the same layer and I would like to account for the distance of meanders in the stream if possible. I was able to calculate ...
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Flow direction outputs (ArcGIS Pro: Hydrology Tools) returning 255 values rather than 8 (D8 settings)
I am working with 10-meter resolution digital elevation models to produce flow direction raster images to be used ultimately for the watershed tool in ArcGIS Pro. When I use one DEM at a time, things ...
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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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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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Display line with color gradient (or fade effect) based on the value of the vertices it connects
I have two vertices connected by two lines (we can assume way out and way back from point A to point B). In the picture I represented the lines with two arrows curved by adding a midpoint and its ...
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How to determine North-facing, south, east and west forest edges in QGIS
I am using QGIS.
I have a shapefile with 41 polygons representing forest patches. I want to assess the effect the forest edge direction has on vegetation within the forest patches. I have defined ...
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Why some flow direction cell of GRASS r.watershed have no data value?
Using r.watershed inside QGIS, I am getting no data value along some streams for flow direction.
I tried the r.fill.dir and for the same raster it does not give any no data value for the same cells (...
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