QGIS Lab07 Fall14: QGIS Vector Analysis

Introduction:

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:
    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. The download link of below video is ogg video or mp4 video. You can play it in vlc player or open it in web browser.

The example files that are used in video can be downloaded from here .

Reference:

  1. Chapter 07 of QGIS 2.6 Training Manual

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