Lesson 2: Vector Data

Episode 5: Introduction to Geospatial Concepts

Videos Credits: Claudiu Forgaci, Ana Petrović

Here’s a short introduction to geospatial concepts.

Shape of the Earth

The shape of the earth

Map Projections

Map projection: From the 3D Earth to a 2D map

Coordinate reference systems

Coordinate reference systems (CRS)

Map scale

Check the variations of map scales.

Map scale

Types of geospatial data

Exploring the geospatial data categories.

Challenge: CRS for calculating areas

The challenge is described as CRS for calculating areas and calculating the shortest path.

Solution

The solutions are explained.

Episode 6: Open and Plot Vector Layers

SF package introduction

sf package introduction and installation

Geometry in QGIS and R

A description of geometry in QGIS & R

Import shapefiles

Import the shp files and opening them using st_read()

Question about shapefile metadata

What was the mistake in importing shp?
loading the wrong dataset

Assign Data to an Object

We can assign the existing data to an object in R

Spatial Metadata

Here you can use the st_geometry_type() to read the geometry

With the st_crs() function you can read the CRS of your data

Question about changing the CRS

Can we change the CRS of a shapefile?

st_transform & bbox functions

st_transform() and st_bbox() functions are introduced

Plot a vector layer

plot the vector

Question about the output

Is the output in British?

Plot the vector layer Pt. 2

Plot the vector part 2

Challenge: Import line and point vector layers

Challenge described

Challenge solution explained

Question about the GUI

Does it make a difference to open (double-click) a file using the GUI?

Solution part 2

Episode 7: Explore and plot by vector layer attributes

Query Vector Feature Metadata

Have a look at the metadata of the layer

Explore values

Explore values within an attribute

Question about updating the columns

How could the column be updated?

Subset features

Filter function

Filter function part 2

Challenge: Now with the motorways

Challenge description

Challenge solution

Challenge solution part 2

Question about the summarize length

Summarize length, would you also get a simple feature?

Customize plots

Introduction to plot customization

Tip: Importance of CRS in plotting

The importance of CRS in plotting your data.

Plot customization part 2

Question about the levels specifications

Why do we need to specify the levels?

Answers

Examining and coloring objects

Question about the number of colors

How should we know how many colors we need for the road types?

Question about the color order

Is the order of colors the same as the value orders?