Merge branch '2-vector-cf' into main

config.yaml

@@ -63,6 +63,7 @@ episodes:
 - 02-data-structures.Rmd
 - 03-explore-data.Rmd
 - 04-intro-to-visualisation.Rmd
+- 08-intro-to-geospatial-concepts.Rmd
 - 09-open-and-plot-vector-layers.Rmd
 - 10-explore-and-plot-by-vector-layer-attributes.Rmd
 - 11-plot-multiple-shape-files.Rmd

episodes/08-intro-to-geospatial-concepts.Rmd

@@ -0,0 +1,103 @@
+---
+title: 'Introduction to Geospatial Concepts'
+teaching: 10
+exercises: 2
+bibliography: references.bib
+zotero: true
+---
+
+::: questions
+-   How ...
+:::
+
+::: objectives
+-   Describe ...
+:::
+
+## The shape of the Earth
+
+The shape of the Earth is approximately a sphere which is slightly wider than it is tall, and which is called **ellipsoid**. The true shape of the Earth is an irregular ellipsoid, the so-called **geoid** (@fig-earth).
+
+![The shape of the Earth. Source: United Nations Statistics Division and International Cartographic Association (2012a)](https://unstats.un.org/unsd/geoinfo/ungegn/docs/_data_icacourses/_ImagesModules/_selfstudy/S06_images/S06_03_a00.jpg){#fig-earth}
+
+The most common and basic representation of the position of points on the Earth is the combination of the **geographical latitude and longitude**.
+
+![Geographical latitude and longitude. Source: van der Marel (2014).](fig/latlon.png)
+
+**Meridians** are **vertical** circles with constant longitude, called **great circles**, which run from the North Pole to the South Pole. **Parallels** are **horizontal** circles with constant latitude, which are called **small circles**. Only the equator (the largest parallel) is also a great circle.
+
+The black lines in @fig-latlon show the equator and the prime meridian running through Greenwich, with latitude and longitude labels. The red dotted lines show the meridian and parallel running through Karachi, Pakistan (25°45’N, 67°01’E).
+
+## Map projection
+
+**Map projection** is a systematic transformation of the latitudes and longitudes of locations on the surface of an ellipsoid into locations on a plane. It is a transformation of the three-dimensional Earth’s surface into its two-dimensional representation on a sheet of paper or computer screen (see @fig-projection for a comparison with flattening of an orange peel).
+
+![Map projection represented as flattening an orange peel. Source: Data Carpentry (2023)](https://datacarpentry.org/organization-geospatial/fig/orange-peel-earth.jpg){#fig-projection}
+
+Many different map projections are in use for different purposes. Generally, they can be categorised into the following groups: cylindrical, conic, and azimuthal (see @fig-projections).
+
+![Cylindrical, conic, and azimuthal map projections. Source: Knippers (2009)](https://kartoweb.itc.nl/geometrics/Bitmaps/Intro%201.9a.gif){#fig-projections}
+
+Each map projection introduces a **distortion** in geometrical elements – **distance**, **angle**, and **area**. Depending on which of these geometrical elements are more relevant for a specific map, we can choose an appropriate map projection. **Conformal projections** are the best for preserving angles between any two curves; **equal area (equivalent) projections** preserve the area or scale; **equal distance (conventional) projections** are the best for preserving distances.
+
+## Coordinate reference systems (CRS)
+
+A **coordinate reference system (CRS)** is a coordinate-based local, regional or global system for locating geographical entities, which uses a specific map projection. It defines how the two-dimensional, projected map relates to real places on the Earth.
+
+All coordinate reference systems are included in a public registry called the **EPSG Geodetic Parameter Dataset (EPSG registry)**, initiated in 1985 by a member of the European Petroleum Survey Group (EPSG). Each CRS has a unique **EPSG code**, which makes it possible to easily identify them among the large number of CRS. This is particularly important for transforming spatial data from one CRS to another.
+
+Some of the most commonly used CRS in the Netherlands are the following:
+
+-   **World Geodetic System 1984 (WGS84)** is the best known global reference system (EPSG:4326).
+-   **European Terrestrial Reference System 1989 (ETRS89)** is the standard coordinate system for Europe (EPSG:4258).
+-   The most popular projected CRS in the Netherlands is ‘Stelsel van de Rijksdriehoeksmeting (RD)’ registered in EPSG as **Amersfoort / RD New (EPSG:28992)**.
+
+The main parameters of each CRS are the following:
+
+-   **Datum** is a model of the shape of the Earth, which specifies how a coordinate system is linked to the Earth, e.g. how to define the origin of the coordinate axis – where (0,0) is. It has angular units (degrees).
+-   **Projection** is mathematical transformation of the angular measurements on the Earth to linear units (e.g. meters) on a flat surface (paper or a computer screen).
+-   **Additional parameters**, such as a definition of the centre of the map, are often necessary to create the full CRS.
+
+In this workshop, we use two CRS shown in @tbl-crs.
+
+|                | WGS 84 (EPSG:4326)                                       | Amersfoort / RD New (EPSG:28992)                |
+|-----------------|----------------------------|----------------------------|
+| Units          | degrees                                                  | meters                                          |
+| Projection     | Geographic (uses latitude and longitude for coordinates) |                                                 |
+|                | Dynamic (relies on a datum which is not plate-fixed)     | Static (relies on a datum which is plate-fixed) |
+| Celestial body | Earth                                                    |                                                 |
+| Datum          | World Geodetic System 1984 ensemble                      | Amersfoort                                      |
+| Method         | Lat/long (Geodetic alias)                                | Oblique Stereographic Alternative               |
+| Prime meridian | Greenwich                                                |                                                 |
+| Ellipsoid      |                                                          | Bessel 1841                                     |
+
+: Main properties of WGS 84 and Amersfoort / RD New coordinate reference systems {#tbl-crs}
+
+## Map scale
+
+**Map scale** measures the ratio between distance on a map and the corresponding distance on the ground. For example, on a 1:100 000 scale map, 1cm on the map equals 1km (100 000 cm) on the ground. Map scale can be expressed in the following three ways:
+
+-   Verbal: 1 centimetre represents 250 meters
+-   Fraction: 1:25000
+-   Graphic:
+
+::: callout
+# Useful resources
+
+-   Campbell, J., Shin, M. E. (2011). Essentials of Geographic Information Systems. Textbooks. 2. <https://digitalcommons.liberty.edu/textbooks/2> (Accessed 22-01-2024)
+
+-   Data Carpentry (2023): Introduction to Geospatial Concepts. Coordinate Reference Systems. <https://datacarpentry.org/organization-geospatial/03-crs.html> (Accessed 22-01-2024)
+
+-   GeoRepository (2024): EPSG Geodetic Parameter Dataset <https://epsg.org/home.html> (Accessed 22-01-2024)
+
+-   Klokan Technologies GmbH (2022) <https://epsg.io/> (Accessed 22-01-2024)
+
+-   United Nations Statistics Division and International Cartographic Association (2012b): UNGEGN-ICA webcourse on Toponymy. <https://unstats.un.org/unsd/geoinfo/ungegn/docs/_data_icacourses/2012_Home.html> (Accessed 22-01-2024)
+:::
+
+::: keypoints
+-   Use `.md` files for episodes when you want static content
+-   Use `.Rmd` files for episodes when you need to generate output
+-   Run `sandpaper::check_lesson()` to identify any issues with your lesson
+-   Run `sandpaper::build_lesson()` to preview your lesson locally
+:::

episodes/references.bib

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+
+@article{vandermarel2014,
+	title = {Reference Systems for Surveying and Mapping. Lecture Notes},
+	author = {van der Marel, Hans},
+	year = {2014},
+	date = {2014},
+	langid = {en}
+}

renv.lock

@@ -0,0 +1,20 @@
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renv/.gitignore

@@ -0,0 +1,7 @@
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+local/
+cellar/
+lock/
+python/
+sandbox/
+staging/

renv/profiles/lesson-requirements/renv.lock

@@ -104,6 +104,16 @@
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@@ -1041,6 +1075,19 @@
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