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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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 ...
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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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52 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 ...
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128 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 ...
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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 ...
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49 views

How to decide when flood started depending on the rainfall data?

I created a raster with the point values (mm) of rainfall data by interpolation in the raster menu. So I have a raster rainfall data and a DEM. With this rainfall data and a DEM corresponding to ...
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-1 value in NextDownId attribute in drainageline

I'm currently working on adjoining catchments in Arc Hydro Tools and I have noticed that there are catchments that are not adjoined. I checked all the generated datasets and found out that the ...
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231 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?