This is seventh video tutorial of QGIS. It is about vector analysis. It contains example problem. The objective is to ask a question and solve it using analysis tools.
- The GIS Process:
- State the Problem
- Get the Data
- Analyze the Problem
- Present the Results
- The Problem:
- It needs to be in Swellendam.
- It must be within reasonable driving distance of a school (say 1km).
- It must be more than 100m squared in size.
- Closer than 50m to a main road.
- Closer than 500m to a restaurant.
- The data:
- The residential properties (buildings) in the area.
- The roads in and around the town.
- The location of schools and restaurants.
- The size of buildings.
- Vector > Geoprocessing Tools > Buffer
- Vector > Geoprocessing Tools > Intersect
- Vector > Research Tools > Select by Location
- Layer > Query (ctrl + F)
- Field Calculator (press ctrl + I in attribute table window)
- Creating Data by downloading OSM file (osm_data.osm) of given region. lat: -33.9757, -34.0877 Lon: 20.353, 20.5278
- Extraction following data:
- Convert crs to 34S
- Buffer road to 50m and schools to 1KM
- Find overlaping area by intersect and save it as road_school_buffers_intersect.shp
- Select houses in that region by location and save it to well_located_houses.shp.
- Create buffer to resturant and save it as houses_restaurants_500m.
- Repeat step 7.
- Select Buildings of the Right Size by creating area column and using query filter (ctrl + F).
- Saving result in solution.shp
The example files that are used in video can be downloaded from here .