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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1answer
50 views

Problem with flow lines in ArcMap

As a part of my PhD I have to map the rivers of Northern Peloponnese, Greece. I have downloaded two DEMs from Nasa Reverb, which I connected with "mosaic to new raster". I have started the usual ...
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0answers
27 views

Problem with making raster from Aspect and wind direction data [duplicate]

I know its not correct to ask for work flow, but I am learning by doing and now I don't know how to move on. I'm trying to make new raster which will represent the facing sides of hill around a ...
0
votes
2answers
32 views

flow direction and flow length in arcmap

I am trying to replicate a flow length calculation in arcmap 10.2. I have an elevation raster with a pixel range from 0 to 3038.96m (32 bit). When I run the flow direction calculation, the pixel range ...
3
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0answers
92 views

Problem with Flow Direction in DEM

I have the following problem with Flow Direction Tool in my DEM and with such wrong calculated flow direction in the centre of DEM I am unable to delineate any watershed. What can I do?
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0answers
66 views

Flow length analysis only shows pixel value, how to get length?

When I create a flow length analysis, and use identify tool on a cell in the layer, it just shows "stretched value" and "pixel value" I don't understand how it's supposed to show length. I'm using ...
1
vote
2answers
128 views

Understanding flow accumulation

I used this youtube video: https://www.youtube.com/watch?v=FSblORbDyhc&list=PLWJ2X2wvq78QRGzl8Un5ADF0_4m5t99iD&index=11 to learn how to run flow accumulation and was successful. I realize it ...
0
votes
0answers
21 views

Is there a way to terminate the Particle Track tool based upon a specific change in direction angle (ArcGIS 10.2)?

I am currently using a Python for loop structure to process a CSV file of coordinate points through the Particle Track tool in Spatial Analyst. I understand from the tool instructions that tracking is ...
0
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0answers
169 views

Determining Flow Direction in ArcGIS for Desktop?

I have a problem with the Flow Direction tool ArcGIS 10.2.2. After running the tool on a digital elevation model in .tif format 16 bit unsigned integer. However the result is an image of 8 bit ...
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0answers
98 views

ArcGIS - Flow Direction (Algorithm)

I am curious about the algorithm of Flow Direction in ArcGIS. Recently I am studying about Hidrology, and I have some questions regard to Flow Direction in GIS. The size of this cell is 100m x 100m, ...
2
votes
2answers
176 views

How to extract elevation values at line start and end points from a DEM?

I am new to the whole gis-experience and need your help working with QGIS. I have: DEM raster with heights (3d) line-shapefile which contains the rivers (2d) I need: heights for "start" and "end" ...
3
votes
1answer
235 views

Flow direction and catchment area polygons for utility water pipes

I'm working on a project where I need to show which direction the water would flow from a water pipe in case there is a pipe burst. I also need to show catchment polygons(area affected). This was ...
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vote
0answers
142 views

Asset point IDs, pipeline and flow direction

I have a data set of a sewage pipe network and point data (assets). I would like to: first calculate the flow direction of pipes (polyline feature) assign IDs to the pipelines using asset IDs ...
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0answers
56 views

ArcGIS ArcMap average values in a single flowline

I am newbie in Arcmap. I need to get the average (Velocity) values of 1000 points on my long flowline. I tried to make parallel lines on each gridpoint using the "copy Parallel" function. But there ...
3
votes
1answer
62 views

Exporting massive gps tracks to a map

I have about 1000 vehicle equiped by a GPS sensor and 3G connection. Each vehicle feeds a csv file -using 3G connection- with its current location every 5 sec. Each vehicle have its own CSV file. ...
2
votes
1answer
154 views

How to extract drainage network through gdaldem

From gdaldem I can view slope, aspect, and hillshade maps. "gdaldem slope manj.tif ouoi.tif -p -s 60" "gdaldem aspect manj.tif gg.tif" "gdaldem hillshade manj.tif hh.tif" Is there any command to ...
5
votes
1answer
1k views

How to assign correct flow direction to stream network polylines?

I would like to create a map showing the results of watershed analysis as well as the resulting stream network with flow direction. I have a stream network which has been created from the flow ...
1
vote
1answer
91 views

How to create a barrier feature class to use in a geometric network?

I am working with the NHD and need to isolate stream segments upstream of barriers. I have too many barriers (thousands) to do this manually using the Geometric Network barrier tool on the toolbar. ...
2
votes
0answers
160 views

How to add flow arrows to groundwater table map?

After I had created groundwater table map, I tried using 3D Analyst>Steepest Path to add groundwater flow arrows to the map. However, it didn't work. Would you please let me know how can I add these ...
1
vote
1answer
73 views

When was MFD renamed to FD8?

According to my understanding, the Multiple Flow Direction (MFD) algorithm was originally defined in The Prediction of Hillslope Flow Paths for Distributed Hydrological Modelling using Digital Terrain ...
4
votes
1answer
449 views

Understanding percentage drop-raster (flow direction-tool)

I'm creating a Topographic Wetness Index using a python script (http://arcscripts.esri.com/details.asp?dbid=16750) As I don't want this just to be a blackbox, I'm trying to understand the different ...
3
votes
2answers
1k views

How to display arrows on pipes from upstream to downstream using QGIS?

I am trying to display arrows on pipes of a sewer network so their direction is from upstream to downstream edges of the pipes. I have managed to display those arrows on a polyline layer (which is ...
1
vote
1answer
728 views

Determine use of pipes in a geometric network

I am trying to understand how to use the Geometric Networks in ArcGis 10.1 For the purpose of my experiment, I built a simple network composed of a few connected pipes, one source (left triangle) and ...
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vote
0answers
612 views

Arrow flow lines from a contour map

using QGIS (or even GRASS) is it possible to label a contour lines shape with arrows that indicate the flow direction? Briefly: I have a point shape with elevation values. I make an interpolation map ...
5
votes
2answers
459 views

R packages for deriving spatial clusters from origin-destination matrix

I have a matrix of origin-destination flows and I am trying to figure out the best way to derive X number of functional spatial clusters from the data. I haven't done this particular type of analysis ...