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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Is there a described GIS method for creating catchment areas based on nearest driving distance?

ie. a combination of Voronoi polygons with isochrones, so that the Voronoi polygons are based on driving distance instead of Euclidean distance. Is there a name or a described method for this?
5
votes
1answer
289 views

Creating dynamic links between features

I currently want to create links between 2 features. Ie., I have 2 basins that flow out and I want to use a line/polyline to have a link out of them and both point to a common 3rd feature, indicating ...
4
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1answer
2k views

How to create a catchment from a point using a DTM raster in QGIS?

I need to find a better way to delineate a catchment from a given point on a watercourse using a DTM - currently I am either using FEH, or if the catchment is too small using contours to draw manually....
4
votes
2answers
797 views

Find locations of raster maximum within polygons: Basin Delineation

I'm trying to identify the Location (lat/lon) and upstream area of every raster point that flows into the Arctic Ocean (there are a lot so it has to be fully automated). I'm starting with the ...
4
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1answer
703 views

Edit existing polygons to include several new nodes

I want to define catchments which are quite large from vector contour data. I normally start zoomed out to define the catchment generally as it is easier to see. I then zoom in and refine the ...
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3answers
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River drainage basin boundary

I'm looking for a set of outlines of the river basins in the UK - I don't need a particularly detailed or highly accurate map - just a map saying point X will drain into the Thames or point Y will ...
3
votes
1answer
1k views

How to obtain statistics within a Buffer/Catchment in MapInfo?

I need to calculate the population statistics within a 10 minute drivetime catchment from a point and within 1 Km Buffer from a point in MapInfo, how can I do that can someone please elaborate? I have ...
3
votes
1answer
456 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 ...
3
votes
0answers
51 views

Multiple watershed delination with QGIS

I am trying to divide a DTM model in subbasins but I have set specific outlet points for the subbasins, and not to use a thershold. Is there a tool similar to r.water.outlet but with multiple outlet ...
2
votes
1answer
49 views

What's the syntax to skip optional saga:catchmentareaparallel parameters?

In PyQGis, I want to use saga:catchmentareaparallel algorithm, in the parameters there is an optional arguments, and I don't want to use them, what is the value should i put on the argument? i try to ...
2
votes
0answers
35 views

Comparing areas of two raster files

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 ...
2
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0answers
64 views

Can 2 GIS layers which representing the same area be compared directly while having the same datum but different coordinate system?

My question is about how coordinate systems affect comparison of different layers - I have tried to refresh my memory about coordinate systems in GIS, but am still unsure about this situation. I am ...
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1answer
42 views

How to compute drive access to a station based on vehicle origin points? [closed]

I have a shapefile that contains station locations and another shapefile that is the geocoded origins of those who drove to the station. I would like to make a buffer around the station that shows the ...
1
vote
1answer
59 views

Choosing projection for calculating 2D 3D area in New Zealand?

I'm trying to use Surface Volume tool in ArcMap to calculate 2D and 3D area of a catchment. What would be the best projection to use and how do i check the maximum error of the estimation?
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vote
1answer
33 views

How to show objects inside an area?

I have two different shape: point shape file with many elements area shape file with many regions I need to create a rule where I need to colur differently the points in some areas, but the areas ...
1
vote
1answer
812 views

catchment area using SAGA and Arcgis 10.2

I would like to calculate catchment area. I used D8 algorithm and running in both arcgis 10.2 and SAGA GIS 2.1.2. However, the results from two software are different. The lowest value of catchment ...
1
vote
1answer
131 views

Managing large number of catchments/watersheds

Does anyone know of an easy way to manage a large number (10,000's) of catchments/watersheds? I have defined a stream network and for each segment, I have a corresponding catchment (in a unique ...
1
vote
0answers
14 views

Calculate how to cover an area by recepetion tovwers

I am working in a Nature Reserve and we are putting up towers that will be used to to track certain animal with collars on. The towers work on line of site only. We must place the towers in a matter ...
1
vote
1answer
25 views

Does Scimap work with QGIS?

Does anybody know if Scimap ( http://www.scimap.org.uk ) works with QGIS? I know it is supposed to operate with ArcGIS and SAGA but as I am very much a beginner with QGIS I would like to know if its ...
1
vote
0answers
111 views

Catchment area calculation

I have a conundrum. I am trying to shortlist optimal physical locations in my county for developing recycling centres that serve the population. I have a vector point layer of the centre point of ...
1
vote
0answers
211 views

QGIS 2.0 Catchment areas by using a 1 hour walking time

i would like to have catchment areas around my points which show the area of an one hour walk. I looked around and found information about using the hiking funktion for calculating a distance with the ...
0
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1answer
350 views

Efficient algorithms for recovering watershed boundaries?

This is somewhat related to a previous question I asked: What Algorithm is used by ArcGIS Watershed tool? I was wondering if there is a more efficient way to calculate catchment areas if you are ...
0
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1answer
34 views

Seperate Intersected layers (as points)

I'm trying to establish watershed outlets as points with two shape files that I have available; i.The watersheds polygons ii. The river network As I said above I'm trying to define the outlets but ...
0
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1answer
135 views

How to create a catchment area using LSOA and point file data [closed]

I have to create a catchment area (based on LSOA) for the 19 underground stations within Camden borough and it has to be in a polygon vector file. I know I have to somehow group the SOAs but don’t ...
0
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0answers
33 views

Setting up a simple catchment area for shops using QGIS?

I would love to set up a catchment area around simple dots on a network map. The catchment should be separated by different range-areas (50, 100, 200m), just like isochrones. I tried the GRASS plugin ...
0
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0answers
41 views

Query processing time for network table creation using pgRouting 1.05

I am trying to follow these steps for creation of a network table using pgRouting 1.05. In my case I have two road geometry tables, one is bangalore_road and the other is all_india_roads. Obviously ...
0
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0answers
340 views

How to calculate Gradient from DEM?

I have a digital elevation model for a catchment area and I would like to calculate the gradient by cells. Is that possible and does anybody know the steps?