Geographic Information Systems

Questions tagged [rivers]

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A river is a flowing body of water

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51 views

Buffering river but it came out as circle

I'm buffering a river using QGIS 3. I am using 30 meters for my buffer. My problem is the buffers came out as a circle, not following the lines. This is what happens during my buffer
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2answers
64 views

Finding rivers from GeoTIFF files with GDAL

I've grabbed a bunch of .tif-files (from http://dwtkns.com/srtm/) and I am trying to render it in 3D as terrain. I've converted it to a 16-bit heightmap successfully but I am curious is there any way ...
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0answers
41 views

Converting River Channel Cross-Section Data to Bathymetry

I have multiple surveyed cross-sections of river channels and need to convert this data into 3D polylines (shapefile) for use in a hydraulic model. The cross-section data is typically supplied in &...
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18 views

Looking for rivers data of South Italy

I am working on a twelfth-century description of South Italy (Calabria, Apulia and Campania) which describes rivers that are now dried up. I am attempting to create maps which reflect the description ...
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27 views

River flow accumulation: % upstream deforestation area as input

I am trying to create a 'flow accumulation' raster whereby each river pixel tells me the % upstream area that has been deforested. This screenshot shows the HydroSHEDS Flow Accumulation dataset. I ...
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1answer
61 views

Understanding DEM of difference results in ArcGIS Pro [closed]

I am looking at channel change in a river in the UK and am using three DTM rasters to observe change over time. One of the methods I am using is to simply minus one DTM from another. I have got the ...
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0answers
42 views

Counting upstream dams along river network in QGIS

I am working on QGIS. I have a river network where each segment is a line with ID from the upstream one (if any) and the downstream one (if any). I also have information on: location of dams location ...
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8 views

Detecting how far a river runs along a boundary between two administrative regions when digitisation errors mean they do not coincide

I am trying to find the lengths of rivers within and on the boundaries of administrative areas ("districts"); I need to distinguish between the length within districts and the length along boundaries (...
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0answers
16 views

Odd false negatives for “distance to route” values when using linear referencing in ArcGIS Pro

I am having a curious problem that I am not sure how to trouble shoot, and I am hoping someone here may have an idea. I have a large array of points (1m X 1m grid), that I have overlaid and clipped ...
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1answer
76 views

Help with Anita Graser's guide on making tapered rivers. River shapefile has “width” field but expression is not working

https://anitagraser.com/2017/04/17/better-river-styles-with-tapered-lines/ This is her expression CASE WHEN "GEW_GRKL" = '< 10 km2 Fluss' THEN 0.2 WHEN "GEW_GRKL" = '10 km2 Fluss' THEN 0.4 WHEN "...
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0answers
82 views

Measure distance to coast along river

I have a dataset on rivers and a dataset on the location of dams. I want to calculate the distance from the dams to the river’s mouth at the coast along the river (not the shortest distance) for those ...
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1answer
91 views

Connecting river segments with R riverdist package

I have imported river courses from OpenStreetMap into QGIS in order to recreate the Rhine river system for analysis in R with the riverdist package. In order to calculate distances between sampling ...
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2answers
92 views

ArcGIS Pro: Create polygons from outlines of unclosed lines

First a disclaimer: I have very little experience with ArcGIS, I usually use QGIS and only recently started using ArcGIS Pro. I have a River dataset from the Natural Earth Site, then made its ...
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1answer
207 views

Line at map scale that do not vanish when zoomed out? (QGIS 3.8)

I'm drawing rivers and roads as linestrings with width set in map units from an attribute. When zooming out, of course they vanish quickly, because 10, 20 or 100m is less than a pixel at 1:100,000 ...
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1answer
46 views

GRASS GIS: creating raster with a certain gradient and extent

Constraints - Use only GRASS GIS - Automated using pyGRASS Input DEM River raster OR river as vector (both are computed) gradient of the valley (as a float) vector line with direction and magnitude ...
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0answers
24 views

Interactive tool for editing TIN data

I created TIN to generate DTM using Mass points from Lidar data and river data that I made from stereoplotting. TIN results show there are several locations where the river elevation floats. So I have ...
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0answers
149 views

Vector map (rivers) to Raster. [ **ERROR 1: Wrong value for -outsize parameter.**]

I want to transform this vector map: To something like this I only tried to convert the vector map through Raster> Conversion> Rasterize But I get this Error: QGIS version: 3.6.3-Noosa QGIS code ...
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1answer
154 views

Removing bridges and dams from DEM

Is there anyway to alter elevation of DEM where there are bridges and dams for the flood routing of the River? I have to calculate discharge of the River from ancient times so at that time there ...
2
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2answers
197 views

GRASS GIS: Computing center line of raster feature representing a river

My goal: Convert a raster layer representing a river feature (see picture) to the center line of the river stored as a polyline feature. Limitation: The whole process has to be automated. I can ...
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1answer
72 views

Linearized map of rivers - what is this called? [closed]

I am looking for a "linearized overview" map (as in the figure below) of the Brahmaputra river. I don't know the exact name of this type of map. Do you have any suggestion on what I should look for, ...
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0answers
56 views

Determining distance to nearest location along stream network by each cell using GRASS?

I have a river network in raster and locations of many dams on the river. In the image above, the BLUE point represent one random cell. Dam 1 is downstream to the cell. I am looking to calculate ...
2
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1answer
144 views

Calculating Distance from Outlet to Dam(s) using ArcGIS Desktop?

I am trying to carry out what should be a relatively simple analysis of river network fragmentation by dams. Similar questions have been asked as: Obtaining length of river upstream of points up to ...
2
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1answer
239 views

Simplifying stream network based on grid using QGIS?

I have a river network (blue line in the below image) and I need to simplify this based on a grid. I basically need to snap the river to the closest vertex or middle-of-side of the grid cell's bounds (...
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1answer
432 views

Cartopy lakes and rivers are clipped

I'm trying to produce a map showing water bodies like oceans/rivers/lakes polygons for purposes of plotting vessel voyages using cartopy. Ultimately I'm looking to create a sea mesh grid using the ...
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2answers
58 views

Calculating percentage (or length) of stream network that is multiple channel streams using ArcGIS Desktop?

I have a polyline stream network of all channels within a drainage basin (which is 1.1 million square km) A number of the rivers in the basin alternate between single thread and multichannel (i.e. ...
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2answers
160 views

Select a specific line length after and before a point

As you can see from the attached image, I have a shapefile of river network (line) and a point shapefile (this one represents the middle point of transects carried out in the area). I'm trying to ...
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1answer
203 views

Rainfall-weighted flow accumulation

I am perfoming a geospatial process whereby I want to use the flow accumulation (as an input for discharge proxy) in calculating stream power. I am using ArcGIS 10.2 So far I have: 1. Valley/channel ...
1
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1answer
46 views

storage in dams on a river system above specific points

I want to find the storage in dams snapped to a set of polylines defining rivers above specific points on each river. Using ArcMap 10.3 I have the polylines representing rivers, the points denoting ...
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0answers
36 views

Assure the continuation of rivers (raster dataset)

I am creating a cost surface raster for identifying least cost paths for road constructions. One of the factors influencing the cost is water cover. I am using Landsat based Global Surface Water ...
2
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1answer
67 views

Cumulative distance along a raster stream network

I am looking to calculate the cells along a stream network from starting points to a maximum distance and stopping points. I need something like r.cost in GRASS (https://grass.osgeo.org/grass75/...
3
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2answers
203 views

How can the flow accumulation in a hydrological model/stream network be maintained across tiles of a large area of interest?

My study area is too large to be processed in its entireity by any hydrological modelling software I have found yet. I will have to break it up in to smaller areas, but there will be flow across these ...
2
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1answer
319 views

Calculate mileage river network

We have a river network which doesn’t correspond to the reality shown by the orthoimage. Each river has the same route number (see attribute table). Every route number has several segments (see ...
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0answers
88 views

DEM provided contains high elevations (trees) that I wish to remove - is this possible

I wish to remove trees off my 3D aerial (high elevations). The files provided are .tif - unfortunately the trees are causing quite a bit of noise. Is there a way to set an elevation to remove them? ...
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1answer
281 views

Building walls to correct channelized flow in ArcHydro

My current project entails burning in a known river network into a high resolution (10x10m) DEM. In doing so, I'm attempting to build walls to correct for channelized flow in the DEM, in order to ...
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0answers
32 views

Can I determine hydraulic load on river bank with hec-ras? [closed]

I want to calculate the force exerted by wave action on river bank. If I know the discharge, flow rate and water level, can I calculate the hydraulic load acting on river bank with hec-ras? If not,...
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0answers
39 views

SAGA Maximum Flow Length problems with the Coordinate systems

I'm new to SAGA. I've got a srtm data set from europe and want to charge the maximum flow length especially from the river Elbe. The data is in WGS84 So first I ran the tool "Fill Sinks"(Wang & ...
5
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1answer
306 views

Calculate Polygon Centerline with a LeastCostPath approach

I'm working on deriving the centerline of a polygon, similar to this question or this one, using a different approach. I'm 90% done with the task, but cannot reach the final step. My approach is to ...
0
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1answer
375 views

Calculate river distance to headwater for every pixel?

I already posted a similar question a few weeks before. But since my dataset changed and I still havent solved it, I thought its good to post a new question instead of editing the old. Using ArcGIS ...
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1answer
114 views

Extract polygon from stream line

I would like to delineate the polygon of a basin from an already delineated stream work. In the example, I want to extract an approximate polygon from the selected stream network in yellow without ...
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1answer
204 views

River network distance from each raster cell

I have a river network shape (or raster) and need to calculate the distance (river, not straight line!) for each pixel (or if not possible for lets say every 10 meters or for a random set of points) ...
2
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1answer
753 views

Distance from one point to multiple points WITHIN a shapefile [duplicate]

I am looking to calculate the distance from a main point to multiple points WITHIN shapefile. In other words: I have a main point at the mouth of a creek. I have about 1,200 points at various ...
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1answer
129 views

Counting points B downstream of point A along polyline using GRASS?

How do I determine how many barriers are downstream of each sampling location on a river network using GRASS? Resources I have ~20,000 points, soon to be ~600,000 points, falling on or near a river ...
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1answer
118 views

Stream order from flow accumulation raster

I am looking to get Strahler Stream Order vector from a flow accumulation raster of a river network. I only find solutions with an elevation or direction raster. Can I do this with GRASS?
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1answer
478 views

Making rivers with higher Strahler/stream order wider in QGIS?

I have a river network and the Strahler order of all rivers in it. Now I would like to create a map similar to this one http://www.hydrosheds.org/, i.e. with rivers of a higher Strahler order being ...
3
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1answer
246 views

Finding distance from river outlet to points, following river, using ArcGIS Desktop?

I have a line (the river (in blue)) and a shapefile of points (plants colonies (in orange)) and I need to find the distance between the river outlet and many points along the river instead of "as the ...
1
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1answer
28 views

Is there a United States waterbody index number available?

In searching for this, I see that in some countries they have a waterbody index number, a unique ID for each water body. Does such a system exist in the US and is it available online or from any ...
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2answers
89 views

Creating DEM using ArcGIS Desktop?

I am new in this field and I am having a problem with my DEM, (SRTM 30M). When I calculate flow accumulation a straight line appears if I fill the DEM. And rivers are not connected if I don't fill ...
4
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1answer
387 views

Obtaining length of river upstream of points up to next point using ArcGIS Desktop?

I am carrying out a study which aim is to come up with a list of priority obstacles to fish migration to be removed based on those where more extra habitat would be created after the modification. I ...
0
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1answer
50 views

Number points along polyline while keeping information on preceding point

I'm working with river networks and need to create ID for points along it. Trick is that points need to have its own ID and also keep the ID of the preceding point (in two separate columns of course)....
6
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1answer
269 views

Missing/inconsistent River Thames map data in Overpass Turbo

I have noticed the River Thames cut off quite abruptly when applying the following query to Overpass: ( way["natural"="water"]({{bbox}}); ); out body; >; out skel qt; The resulting data is ...

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