If you prefer to print out the whole document, please find the pdf version in the section of supervision on RM03 Moodle page.

Assignment for Supervision 1

Submission Dealine: 24 Feb (Tuesday) 12:00pm, 2021

Instructions

  1. Please download and install QGIS standalone install version according to your platform: Download QGIS
  2. Read through the tasks carefully. You may face problems if you overlook any of the steps.
  3. Remember to save the QGIS document regularly.
  4. Read through the instruction carefully. You may face problems if you overlook any of the steps.
  5. Please write your answers in a new blank word document and submit on Moodle. \

Note: functions and filename are highlighted in this document.

Assignment overview

In this assignment, you will extract the wards in the Cambridge city area using the Cambridgeshire data. After that, you will link the population data to the respective wards, and compute the population density of each ward. Lastly, you will symbolize population density in Cambridge.

Tasks

  1. Download Cambridge District Wards data of Cambridgeshire from Cambridgeshire Insight Open Data and import the shapefile into QGIS.
    Hint: set up project properties including CRS.

  2. By using Select features or Select features using an expression to create a new shapefile for the wards of Cambridge City. This shapefile will include these wards: Abbey, Arbury, Castle, Cherry Hinton, Coleridge, East Chesterton, King’s Hedges, Market, Newnham, Petersfield, Queen Edith’s, Romsey, Trumpington and West Chesterton. Name this file as Cam_City.shp with choosing CRS EPSG:27700.
    Hint: Use Select features or Selection using expression command to export the data to a new shapefile.

  3. Download Cambridge population estimates data(2015) from: 2015-based population forecasts for Cambridge

  4. Open it in excel and comprise only one sheet, containing five columns, Ward Code, Ward name, Y2011, Y2016 and Y2021.

  5. Import the CSV file into QGIS.
    Hint: drag file into QGIS or add csv through Data Source Manager.

Question A: Which ward has the highest and lowest population in 2011, 2016 and 2021? Tabulate and also write respective population.

  1. Right-click the Cam_City and click the Properties option. Switch to the Joins section on the side and click the Add button to join the population table 2015-based population forecasts for Cambridge to the Cam_City shapefile. Select Ward name as Join field and wd15nm as Target field. Once this is done, the Attribute Table of Cam_City shapefile should show the Ward name and the population of each ward in 2011, 2016 and 2021.

  2. Use the Export command to create a new shapefile, name it as Cam_City_Pop.shp. The Attribute Table of this shapefile must be showing the ward names as well as the corresponding population in 2011, 2016 and 2021. \

  3. In the Attribute Table of Cam_City_Pop shapefile, click Open field calculator. Create a new field named as Ward_Area and set the output field type to ‘Decimal number (real)’, Precision = 4 and Scale = 2. In the expression window, input $area/1000000 and it will compute the area for each ward in km2 (sq kilometres).
    Note: you can find $area in the right list under Geometry section.

Question B: Why did we use Decimal number as the data type while adding the field Ward_Area in the Attribute Table of Cam_City_Pop shapefile? What is the purpose of setting the Field langth and Precision values?

Question C: Which ward is the largest and smallest in terms of area? Also note their areas in km2.

  1. In the Attribute Table of Cam_City_Pop shapefile, click Open field calculator. Create another new field named as Pop_Den11 and set the output field type to ‘Decimal number (real)’, Precision = 7 and Scale = 2. In the expression window, input Pop_Y2011/Ward_Area and We will compute population density, number of population per km2 in each ward. Repeat this step to create Pop_Den16 and Pop_Den21, and calculate density for 2016 and 2021.

Question D: Which ward has the highest and lowest population densities in 2011, 2016 and 2021? Tabulate and also write respective population densities.

10.Symbolised cambridge map in Categorized color by Pop_Den21 (per km2) of 2021 and export the map.
Hint: nevigate to Project > Import/Export > Export Map to Image in menu bar and set Extent by Calculate from layer(Cam_City_Pop)`. Please insert the exported image into your assginment.

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