QGIS Vector Analysis

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.

Summary:

1. The GIS Process:
   1. State the Problem
   2. Get the Data
   3. Analyze the Problem
   4. Present the Results
2. The Problem:
   1. It needs to be in Swellendam.
   2. It must be within reasonable driving distance of a school (say 1km).
   3. It must be more than 100m squared in size.
   4. Closer than 50m to a main road.
   5. Closer than 500m to a restaurant.
3. The data:
   1. The residential properties (buildings) in the area.
   2. The roads in and around the town.
   3. The location of schools and restaurants.
   4. The size of buildings.
4. Solution:
   1. Vector > Geoprocessing Tools > Buffer
   2. Vector > Geoprocessing Tools > Intersect
   3. Vector > Research Tools > Select by Location
   4. Layer > Query (ctrl + F)
   5. Field Calculator (press ctrl + I in attribute table window)
   6. Creating Data by downloading OSM file (osm_data.osm) of given region. lat: -33.9757, -34.0877 Lon: 20.353, 20.5278
   7. Extraction following data:
      1. Details of Shape files, Query and Project folder.

         1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

         Source of shp files: a. For schools.shp,    from multipolygons layer. b. For resturants.shp, from multipolygons layer c. For roads.shp,      from lines layer d. For houses.shp,     from multipolygons layer Queries: a. For schools.shp: “amenity” = school, b. For resturants.shp: “amenity” = resturant c. For roads.shp: “highway” != ‘NULL’ AND “highway” != ‘unclassified’ AND “highway” !=‘track’ AND “highway” != ‘path’ AND “highway” != ‘footway’ d. houses.shp: “building” !=‘church’ AND “building” !=‘commercial’ AND “building” !=‘garage’ AND “building” != ‘hangar’ AND “building” != ‘retail’ AND “building” != ‘telephone_exchange’ Output Project  = analysis.qgs folder          = residential_development

   8. Convert crs to 34S
   9. Buffer road to 50m and schools to 1KM
   10. Find overlaping area by intersect and save it as road_school_buffers_intersect.shp
   11. Select houses in that region by location and save it to well_located_houses.shp.
   12. Create buffer to resturant and save it as houses_restaurants_500m.
   13. Repeat step 7.
   14. Select Buildings of the Right Size by creating area column and using query filter (ctrl + F).
   15. Saving result in solution.shp

Below is the full video lecture. Use full screen for clear content of video.