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How do you calculate the distance of about 10 sites scattered across a region to bodies of water (rivers and lakes) using ArcGIS 10.1?

I have the lat/lon coordinates of the 10 sites as a point feature class and I have downloaded the Surface Water Area (polygon shapefile) for the study area from the UK Ordnance Survey webpage.

I want to determine the easiest route-ways that are available in the study area by taking into account slope and proximity to rivers. I understand that I can achieve this by running a cost path analysis if I have a dem raster, slope raster and distance rasters to rivers and valley floors. But I am not sure how to create distance rasters to rivers and valley floors using Spatial analyst tools.

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  • Maybe look at the Near geoprocessing tool? But the distances you get will be straight 'as the crow flies' rather than crenulated 'as the water flows'. Perhaps not adequate?
    – MC5
    Commented Dec 1, 2013 at 14:51
  • Thanks, I'll have a look at that, but given that I am looking at an extremely undulating landscape I am not sure whether this is appropriate - in any case, thanks for the suggestion - i'll give it go!
    – user19622
    Commented Dec 2, 2013 at 5:15
  • is there any other options?
    – user19622
    Commented Dec 2, 2013 at 12:30

2 Answers 2

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If you have the Spatial Analyst extension, it sounds like you may be able to make use of the Path Distance tool. You will need an elevation raster to serve as input. The tool will output a raster with a value in each cell that represents the shortest distance to one of your points from that cell, taking the topography into account in its calculations.

Of course this is assuming you're looking for overland and not hydrologic distance.

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If you are wanting to use slope as a factor you will have to use a DTM anyway, https://www.ordnancesurvey.co.uk/opendatadownload/products.html use "OS Terrain 50" and make sure the Supply Format is "ASCII Grid" so you get a raster. the Slope tool is Spatial analyst>Surface >slope.

Are the 10 sites on the water feature? As if they are you could just either split the feature or create and trace a polyline between each of the site and calulate the length

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  • thanks for that! the ten sites are not on the water feature. what I basically want to do is display a set of overlapping polylines (for which I don't have a start and destination points) with each polyline representing a cost-least path on the landscape. I also want these paths to be determined by low angle slope and proximity to riverways - in other words valleys. Is this possible? any advice would be massively appreciated!
    – user19622
    Commented Dec 10, 2013 at 6:06

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