# Traveling Salesman Approach to Visiting Data-loggers II

Dec 23, 2008 metroadmin**Premise:**

Updated version of a previous attempt to use a traveling-salesman approach to visiting data-loggers in steep terrain. This time we use a vector/raster approach (v.rast.stats) to compute the total "cost" incurred along each segment of a network connecting all of our data-loggers. Although this approach requires more computation time (v.rast.stats is slow), we can generate a more detailed cost surface to model movement. In this case we are using a cumulative-traversed-slope derived cost, with a 90% reduction along a local road.

**New Approach:**

- generate a cumulative cost surface, originating at data-logger locations, based on slope angle (r.slope.aspect, r.cost)
- generate a network of lines connecting all data-loggers, along with a local road (v.delaunay, v.digit, v.patch)
- modify the cost surface along the local road, such that cumulative cost is reduced 90% within 5m of the road (r.buffer, r.mapcalc)
- densify the line segments along the network (v.split)
- compute the total cost along each line segment of our network (v.rast.stats)
- connect data-logger points to delaunay network (v.net)
- solve the traveling salesman problem (v.net.salesman)

**Setup the cost surface and network**

**Compute the total cost along each line segment, solve traveling salesman problem**

### Links:

Traveling Salesman Approach to Visiting Data-loggers

Vector Operations

Working with transects

## Software

- General Purpose Programming with Scripting Languages
- LaTeX Tips and Tricks
- PostGIS: Spatially enabled Relational Database Sytem
- PROJ: forward and reverse geographic projections
- GDAL and OGR: geodata conversion and re-projection tools
- R: advanced statistical package
- GRASS GIS: raster, vector, and imagery analysis
- Generic Mapping Tools: high quality map production