LESSOn 6
Geodata
Geodata & Journalism
Geographic Projections
and Coordinate Systems
Geodata Types and Formats
Geographic Projections
and Coordinate Systems
Geodata Types and Formats
Geodata & Journalism
The main difference between conventional data-journalism and geodata-based journalism is that geodata-driven articles have maps.
In the maps, we show the results of geo-referenced data analysis. We draw connections between locations and their numerical characterisations, visually displaying the weight and value of geo-referenced processes.
The geodata-journalists use both Cartography and Geographic Information Systems (GIS).
1. Cartography is about visual representation of geospatial data. Tools: DataWrapper, Flourish.
2. GIS is about the analysis of the spatial relationship between elements on a map. Tool: QGis.
In the maps, we show the results of geo-referenced data analysis. We draw connections between locations and their numerical characterisations, visually displaying the weight and value of geo-referenced processes.
The geodata-journalists use both Cartography and Geographic Information Systems (GIS).
1. Cartography is about visual representation of geospatial data. Tools: DataWrapper, Flourish.
2. GIS is about the analysis of the spatial relationship between elements on a map. Tool: QGis.
If you just put the data you found online in the programme and download a ready picture without any manipulations with the data, it is cartography.
If you calculate anything, join the data — both by attributes and location, merge and divide the elements, creating new data from the existing data — it is GIS.
Inspirational articles:
- Why reporters and newsrooms should use geodata — Gustavo Faleiros, International Journalists' Network
- Geographic information systems: a use case for journalists — Jacques Marcoux, DataJournalism.com
- How Maps Help the Media See What Others Can’t — Robby Deming, ESRI Blog
Secret 1
Urban studies is the most fertile ground for data storytelling because:
- there's a lot of data;
- a lot of money spent on maintaining data infrastructure;
- a lot of diverse specialists.
Interesting projects
- How we find our way — Outside — a stunning insight into the history of cartography with a lot of links to other projects
- The Most Detailed Map of Cancer-Causing Industrial Air Pollution in the U.S. — ProPublica.
- Mapping Historical New York: A Digital Atlas
- The Toll of Eight Days of Conflict in Gaza and Israel — The New York Times
- MTA Ridership Changes due to Covid-19 — TWO-N Inc.
- Since When Have Trees Existed Only for Rich Americans? — The New York Times
- Native Land Map — Gaia GPS — the map shows North America according to the Indigenous nations and communities' areas, rather than state and country borders
- Hoodmaps — mental maps of cities around the world
- Naivemaps — Russia in the eyes of its own citizens, these maps are analysed using the Bertin's visual variables
Secret 2
Datafication has been criticized for its excessive surveillance of people, but it also allows problems to be uncovered and solved.
Secret 3
In urban studies, telling engaging stories is easiest. Why?
The most effective storytelling strategy is to place people at the center of the narrative, and people live in the city.
Coordinate Systems
Where to find the coordinates of the place? Go to Google Maps — right mouse click — see "Y, X" in the first row.
The coordinate systems may be geographic and projected.
The geographic coordinates are measured in degrees. Hence:
The projected coordinates are measured in meters and can be huge. For Moscow:
The Earth's current international standard prime meridian is the IERS Reference Meridian, derived from the Greenwich Meridian.
- Longitude = long = X = λ = долгота // меридианы
- Latitude = lat = Y = φ = широта // параллели
The coordinate systems may be geographic and projected.
The geographic coordinates are measured in degrees. Hence:
- | latitude | =< 90°,
- | longitude | =< 180°,
- the starting point is the prime meridian (longitude = 0°) and the Equator (latitude= 0°).
The projected coordinates are measured in meters and can be huge. For Moscow:
- X (longitude) ≈ 411 170,
- Y (latitude) ≈ 6 180 137,
- the starting point is the edge of the time zone (longitude = 0) and the Equator (latitude= 0).
The Earth's current international standard prime meridian is the IERS Reference Meridian, derived from the Greenwich Meridian.
The "default" international projection is the World Geodetic System (WGS-84). Usually the data you find online are represented in this coordinate system. But throughout the history there was a lot of different systems of different origins and methodologies.
Some countries still have their own coordinate system due to security concerns. For instance, in China are used GCJ-02 and BD-09 — they are based on the WGS-84, but apply an addional obfuscation algorithm, so that the locations are in fact several kilometers apart from their coordinates in WGS-84. Officially, the translation from BD-09 and GCJ-02 to WGS-84 is illegal, but you may still find such algorithms online.
Learn more about the Chinese coordinates systems:
- GCJ-02(gcj 02) Explained. A Short Guide To The Chinese Coordinate System — AbstractKitchen
- Restrictions on geographic data in China — Wikipedia
Projections
Projections are used to translate 3D geocoordinates in degrees to a 2-dimensional surface in meters.
The most common projection is a combination of WGS-84 and the Universal Transverse Mercator projected coordinate system, also known as UTM zones.
UTM (projection zones) and UTC (time zones) should not be confused. Time zones are not 100% geographically accurate — they vary depending on the political and economic ties of regions.
For instance, the International Date Line — boundary between one calendar day and the next, roughly following the 180° line of longitude — deviates between Russia and the USA, so that Russian territories are in the same time zone and day with other Russian regions — the same for American areas.
The most common projection is a combination of WGS-84 and the Universal Transverse Mercator projected coordinate system, also known as UTM zones.
UTM (projection zones) and UTC (time zones) should not be confused. Time zones are not 100% geographically accurate — they vary depending on the political and economic ties of regions.
For instance, the International Date Line — boundary between one calendar day and the next, roughly following the 180° line of longitude — deviates between Russia and the USA, so that Russian territories are in the same time zone and day with other Russian regions — the same for American areas.
The UTM zone of Moscow is 37N — the 37th zone from the International Date Line in the Northern Hemisphere. That's why, if we count the distance in meters in the territory of Moscow, we use the WGS-84 UTM zone 37N projection.
You may also often see the acronym EPSG. It stands for European Petroleum Survey Group — an organization that maintains a geodetic parameter database with standard codes and coordinate system information. The id for Moscow projection WGS-84 37N in the EPSG system is 32637.
Learn more:
- 5 tools for mastering map projections — Aleks Buczkowski, Geoawesomeness
- Coordinate Systems Worldwide — EPSG (European Petroleum Survey Group)
- Map Projections — University Consortium for Geographic Information Science
- Is WGS84 a Coordinate system or projection system? — StackExchange
- Animation showing how different map projection distort the globe — u/thequickbluefish, r/MapPorn, reddit
- A brief look at map projections — Views of the World
- UTM zones
-
- Time zones, the prime meridian, and the International Date Line
Rescaling coutries
- Select a random country using this site.
- Open The True Size Of.
- Clear the map using the Clear Map button.
- Send a message to our Telegram chat with the country's name, its UTM zone and three screenshots. First of all, write down which country you got.
- Enter your country on the map and screenshot it in its original size. Add the screenshot to your post.
- Drag that country to the Greenland level. Screenshot it and add it to your post.
- Drag this country to the level of Indonesia. Screenshot it and add it to your message.
- Find the capital of your country. Then type “WGS84 capital_in_English UTM zone” into a search engine. For example, WGS84 Moscow UTM zone. Try to find a result with the domain epsg.io in the output. At the end of the zone number, there should be either the letter N or the letter S. Add the UTM zone number to the message.
- Send the message.
Total: country name, UTM zone and three screenshots.
Discussion
How to visualize refugee flows in a way that does not look like an attack by troops and is not associated with a danger to the local population?
- Arrows.
- Rectangles and Dots
- Circles.
- Arcs and Columns
- L'art pour l'art.
Game ‘Find Crimea on the map’
Google Maps are biased
More on this topic
OpenStreetMap — collaborative alternative
Data Types
The geospatial data are a combination of common data and pictures. Hence, the geospatial data are subdivided:
- by the graphics:
- vector data — visual representation of mathematical interconnections,
- raster data — every pixel is representing something on its own.
- quantitative discrete data — like population or the number of anything in a particular location — size + vector,
- quantitative discrete data, normalised to area — like density of population per city — colour + vector,
- quantitative continuous data — colour or texture + raster,
- qualitative data — like the area of the forest or the ethnicity of the resident — colour or texture + vector or raster.
In this course, we will work with the vector data only.
Vector data are subdivided into:
- points (dots),
- lines (two or several connected dots),
- polygons (filled areas with borders).
Learn more:
- Vector vs Raster: What’s the Difference Between GIS Spatial Data Types? — GISGeography
- Types of GIS Data Explored: Vector and Raster — GISLounge
- Introduction to Raster Data — Data Carpentry
- Raster Data — QGIS Documentation
- Vector Data — QGIS Documentation
- Working with vector data — QGIS User Guide
- Working with raster data — QGIS User Guide
Font Style in DataWrapper
<span style="color:#NEEDED_COLOUR;font-weight:bold;font-family: NEEDED_FONT"> Hello! </span>
Data Formats
1. csv and xlsx — already your good old friends.
2. geojson — json with the coordinates.
3. geopackage, gpkg — alsmost the same as geojson: just a file with geodata.
4. kml — you may download your data in this format from Google My Maps (e.g. highway M4 Don) or from Yandex Maps Constructor.
5. wkt — often found on open data portals: first comes the type of vector data in capital letters (POINT, LINESTRING, POLYGON), and then in parentheses — coordinates.
6. shapefile — vector archive that consists of several files, you need all of them, but you shoul upload to QGis only the .shp file.
2. geojson — json with the coordinates.
3. geopackage, gpkg — alsmost the same as geojson: just a file with geodata.
4. kml — you may download your data in this format from Google My Maps (e.g. highway M4 Don) or from Yandex Maps Constructor.
5. wkt — often found on open data portals: first comes the type of vector data in capital letters (POINT, LINESTRING, POLYGON), and then in parentheses — coordinates.
6. shapefile — vector archive that consists of several files, you need all of them, but you shoul upload to QGis only the .shp file.
7. gpx — a route with three parameters:
- waypoints — points of your route when you need to turn left or right,
- routes — planned path,
- tracks — actual path with timestamps; example of usage: Strava (+ Strava Heatmap VPN), Komoot.
If you need to find geodata, just google:
- needed_info geodata
- needed_info geojson
- needed_info shapefile
This is what a shapefile looks like
How to make an interactive map with points
(Locator Map) in DataWrapper
(Locator Map) in DataWrapper
How to add lines to a Locator Map in DataWrapper
in Russian
How to load data into QGIS,
set up the projection and the basemap
and calculate the number of points per polygon
set up the projection and the basemap
and calculate the number of points per polygon
in Russian
How to load Strava data into QGIS
in Russian
Home Assignment
Deadline — 12 March, Thursday, 18:00.
Grading criteria
Grading criteria
Once again an individual task. TUTORIAL ABOVE ↑ (How to make an interactive map with points (Locator Map) in DataWrapper).
Imagine that you want to show a friend your favourite city in the world and your favourite places there.
In Datawrapper, create an interactive map with these places.
Detailed requirements:
You can also create a map not about yourself but about your favourite star, e.g. favourite museums X in city Y.
Create a text document with a title in the format Name_Map and insert a link to your map there (link, not embedding code).
Note that the map needs coordinates in degrees, i.e. go to the Google Maps and copy the coordinates by right clicking on the map and then create the corresponding dataset.
Tutorials on how to make a csv to upload to locator map:
Imagine that you want to show a friend your favourite city in the world and your favourite places there.
In Datawrapper, create an interactive map with these places.
Detailed requirements:
- Locator Map
- Title
- Subtitle with the name of the city
- Map with minimum five points
- The points must be annotated
- Points must have icons that are thematically appropriate
- The tooltips should explain why you care about the place OR why it's worth visiting.
- The map zoom should include all points
- Scale bar
- Credits (your name, city or country, year the visual was created).
You can also create a map not about yourself but about your favourite star, e.g. favourite museums X in city Y.
Create a text document with a title in the format Name_Map and insert a link to your map there (link, not embedding code).
Note that the map needs coordinates in degrees, i.e. go to the Google Maps and copy the coordinates by right clicking on the map and then create the corresponding dataset.
Tutorials on how to make a csv to upload to locator map:
