Saturday, 26 November 2011

Pipeline routing (RMOTC dataset, part V)

As promised last week here is the update to my second most popular Slideshare post: using ArcGIS Model Builder to plan a pipeline route as a function of topography, slope, land cover and cultural data (roads, rivers, wetlands etc.). As RMOTC is remote, see (pardon the pun) it is uninhabited and land cover is uniformly grass- or shrub-land, which has the same IGBP class of 5 (middle-of-the-road).

The model is to plan a route from a fictitious gathering facility in the north of RMOTC, to another fictitious collecting point by the main road in the agglomeration further north (added Gtopo30 DEM data to extend the project further north). Modelling goes through two stages, details available upon request, but you can get started here:
  • first calculate the suitability by converting all to rasters and giving them relative weightings and coming up with a suitability grid
  • second derive a routing along that grid applying weight-costing calculations, these are all functions available in Spatial Analyst

click image to enlarge

I picked a fairly coarse grid of 500 feet, as the 'relief' on the cost-weighting surface is not very pronounced, and more detailed grid yields a rather erratic route. That can be decimated afterwards, or one can simply decimate the data to start with, in other words make a coarse grid. Remember these are simple modelling tools intended to show how GIS can be used out-of-the-box, and not meant to compete with high-end tools.

click image to enlarge

Note in ArcScene, how: 
  • orange squares (high cost) coincide with ridges and rivers
  • green squares (low cost) coincide with valleys and roads
The highest cost escarpments appear further south away from the route. The entire project will be posted here on ArcGIS Online, if you wish to examine in further detail. The model itself and details will also be posted on Dropbox here, same way as the simple reservoir modelling data were before.
Enjoy! Comments and suggestions are of course always welcome...
Note: Model Builder and ArcScene come with the ArcGIS extensions, Spatial Analyst and 3D Analyst, respectively. Nothing was added to these tools, ArcGIS was used out-of-the-box. And if you don't have it, you can get it here for personal use for $100 per annum.
Model Builder is the single key differentiator from other desktop GIS, and you can load models on ArcGIS Server as Geoprocessing services.

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