METHODOLOGY AND FLOW CHART
This study will focus on the area between BlackBull and Punakiki on the West Coast of the South Island of New Zealand. The Pike River Mine is situated in this area. The track will start at Punakiki and end at Blackball. The boundaries of the study area …show more content…
This project will use both raster and vector data, but will ultimately be in raster format.
There are eight factors considered in this analysis: aspect, DoC land, erosion, existing tracks, land use capability, rivers, slope, and vegetation. Each factor has been separated into categories and each category given a rating. A weighting has been assigned to each category. These are set out in the Table 2. North-facing is the important factor of aspect, as it adds to amenity value. Likewise, the proximity to rivers contributes to this, and vegetation type. Vegetation type also must be balanced with conservation needs. Slope and erosion are important factors in the maintenance of tracks, with shallow slopes, and low erosion-prone soils are preferred. DoC Land and existing tracks are preferred as they can reduce the costs of constructing the tracks, and acquiring new land. Land use capability assesses the best use of land for recreation uses, as opposed to economic …show more content…
The clipped layers will have a new field added for the rating, which will be populated using the field calculator. The exceptions to this are the Rivers and Tracks layer. The tracks layer was buffered slightly using the Buffer tool, as it is a line layer, to more accurately represent its presence, due avoid any eventual issues in resolution. The vector layers needed to be converted to raster using the polygon to raster tool, to generate a cost raster map for input into the cost direction tool. A 15m resolution was used to match that of the digital elevation model. The Euclidean distance tool was used on the Clip_Rivers layer to measure the distance each cell is from the river.
The raster part of the analysis is based on a digital elevation model (DEM). The DEM was clipped to the same extent as the vector data using the extract by mask tool. The DEM was the input for the slope and aspect tools to generate these layers.
The slope, aspect, DoC Land, tracks and rivers layers were reclassified using the corresponding ratings in Table 2. Finally an ‘addition’ raster calculation will be used to create the CostMap layer. This will include multiplying each layer by the weighting for that factor, using the following equation:
Cost Map = (Rast_LCDB * 3) + (Reclass_DoC * 2) + (Rast_Erosion * 5) + (Reclass_Tracks * 2)
+ (Reclass_River * 4) + (Reclass_Slope * 5) + (Reclass_Aspect * 4) + (Rast_LandUse *