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Session 4
Primary Data Sources –Part 2
Radar, LIDAR, Drones, Sensors,
Man-made World Data,
Virtual Earths
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Natural World Data
• Last week we looked at
– Surveying
– Air-photography
– Remote Sensing
• Passive, measures reflective radiation
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Active Scanning e.g. Laser-Scanning
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
LIDAR – from Wikipedia
• LIDAR (Light Detection and Ranging) is an optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target.
• The prevalent method to determine distance to an object or surface is to use laser pulses.
• Like the similar radar technology, which uses radio waves instead of light, the range to an object is determined by measuring the time delay between transmission of a pulse and detection of the reflected signal.
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Lidar – Aerial and Terrestrial
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
3D Data from Laser-Scanning
• Can be from the air or from the
ground
• Huge amounts of (x,y,z) data
• Now cheap and quickU3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Data Reduction
• Remember this was a problem with
automated line following (2D)
• Douglas-Peuker algorithm is a typical
solution
– Removes points whilst retaining ‘shape’ to
within a tolerance (έ)
– Operates recursively
• Something analogous has to be done in
3D – not going to tax you with it!U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Lower Manhattan, post 9/11
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Red Mud Disaster in Hungary
mapped by laser-scanning and RS
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Downtown Dublin as a
Lidar Point Cloud• A recent project, reported in January 2020
• See https://www.gim-
international.com/content/article/downtown
-dublin-as-a-lidar-point-cloud for a
comprehensive article
• Watch the video at the end for the
highlights
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Laser-Scanning in support of
Rail Baltica
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
• Existing terrain • A possible bridge
Shuttle Radar Topography Mission
(SRTM) • Most ambitious Global DTM creation programme to
date (in civil domain).
• SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000
• The resolution of the cells of the source data is one arc second, (approx. 30 meter). Since 2015 SRTM data for most of the earth has been publicly available, see: http://www2.jpl.nasa.gov/srtm/index.html
• An good article on SRTM data and where to find it is– https://gisgeography.com/srtm-shuttle-radar-topography-
mission/
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Latest SRTM data release –
Autumn 2017
• SRTM GL1 (SRTM v3.0) provides access to
Global 1 arc second coverage
– 30m. x 30m. grid squares
– Jet Propulsion Laboratory (JPL) identified
different range of accuracy for different
continents. The horizontal accuracy range from
7.2m (Australia) to 12.6 (North America) and the
absolute vertical accuracy between 5.6m (Africa)
to 9m (North America). All at 90% confidence
level.U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Some uses of SRTM data
• Used for gradient profiles on cycle routes
• An SRTM Safari over Northern Tanzania:
– https://www.jpl.nasa.gov/video/details.php?id=
1335
• Investigation of an ancient Cambridge myth
– The Harz Mountains in Germany stand
between us and the Urals
– But there is nothing between the Met Station at
Royston and the North Pole!
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Space Debris
• A recent feasibility exercise on removing
space debris:
– https://eijournal.com/slider-images/possible-
solution-for-space-junk
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
And nowadays, back on Earth
• Drones and UAV’s for mapping are
commonplace:
– At the professional level
• https://www.datamapper.com/
– And for the enthusiastic amateur
• http://geoawesomeness.com/step-step-guide-
complete-first-drone-mapping-project/
– A drone (quadcopter recommended)
– A smartphone mapping app and web platform
– Plan flight and check in field
– Fly and process
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Drones and UAVs
Six years ago
• I watched a tiny plane
loaded with a iPhone
camera make a photo
mosaic of the ETH
Lausanne campus in 20
minutes or so.
• Now a huge growth of the
use of Drones and UAV’s
for mapping. Whole
conferences on the topic.
Shop around, under £1K
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Back on Earth, 5G Network
Planning• In preparation for 5G mobile phone networks,
Ordnance Survey are trialling high density, high
accuracy data collection in the Bournemouth area
– https://www.youtube.com/watch?v=tUmw0RSjzMU&fe
ature=em-subs_digest
– Augmentation of existing framework data
• Compare with the 2G auction (1991) and 3G
(2000) – huge investments, scramble for data,
short timescales, lots of short cuts taken, what
will happen this time?
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Sensor Web
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Errors and Omissions in Maps
• “Elephant Mountain” in NW Gold Coast
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Deliberate Omissions on Maps
• Blank spaces in Ordnance Survey maps
– Censoring of sensitive features started in
1928 and stopped in 2006
• Another far-ranging example was Soviet
military maps in the Cold War era
– Two parallel map series
• Civilian, with all features of military sensitivity
systematically shifted
• Top secret, accurate military maps, loss of which
was a capital offenceU3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
H. A. G. (“Bunny”) Lewis
(1912-2002)• One of the last great British cartographers, a true
polymath
• Chief Map Research Officer, UK MoD
• Consultant Editor of The Times Atlas of the World
• Linguist, fluent in Russian
– Detected the deliberate distortions in Soviet military
maps by reference to Tsarist era maps
– Disbelieved but subsequently vindicated by imagery
– Russians finally came clean as part of Perestroika
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Aside, an interesting talk
coming up• 5.30 pm Tuesday 25 February 2020 in the
Gardiner Room, Emmanuel College, CB2
3AP, free entry.
– John Davies (www.sovietmaps.com ) and
Alex Kent (Canterbury Christ Church
University) on “Secret Soviet Maps of
Cambridge and the World”
– More information about the speakers can be
found at http://redatlasbook.com/authors )
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Nowadays, no place to hide
• Retreat of icecaps and glaciers
• Deforestration, eg in the Amazon basin
• Forced detention/re-education centres for
the Uighurs in China
• All closely monitored by satellite and other
imagery systems
• More to say in a later session
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
‘Man-Made World data’
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Primary Data• Primary data comes direct from source, with no
intermediate ‘interpretation’– Although it may require ‘interpretation’ or ‘processing’ before it can
be used
• Examples from the ‘Real World’ (or ‘Natural World’) include– Survey data
– Aerial photography
– Satellite imagery
– LIDAR data
– SRTM
– Drones and UAV’s
• Examples from the ‘Man Made World’ include– Gazeteers of names
– Post code directories
– Cadastres, or ownership records
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Geocoding
• Geocoding is the process of finding associated geographic coordinates (often expressed as latitude and longitude) from other geographic data, such as street addresses, or zip codes (postal codes). With geographic coordinates the features can be mapped and entered into Geographic Information Systems, or the coordinates can be embedded into media such as digital photographs via geotagging.
• Reverse Geocoding is the opposite: finding an associated textual location such as a street address, from geographic coordinates.
• A geocoder is a piece of software or a (web) service that helps in this process.
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Gazetteers
• ‘Gazetteers are listings of geographic
names. They may include just cities and
towns, or all sorts of geographic features,
and they can vary in the type and amount
of information they provide: some include
only the type of feature and its location,
while others give lengthy descriptions and
histories of a place’.
British LibraryU3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Gazetteers, the A-Z Atlases
• My ‘London’
copy has
– 140 pages of
maps
– 135 pages of
indexes or
gazetteers
• Street names
• Places
• Railway
Stations
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Geographic Names – a
miscellany• The river ‘Afon’ on Celtic
• Directorate of Overseas archive of field
recordings seeking to establish names
– Finally lodged with countries or at the National
Collection of Air Photography
• Alastair MacDonald
• UK Permanent Committee on Geographical
Names works with UN Committee of experts
• Names of Seas - International Hydrographic
Organisation and International Maritime
OrganisationU3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
NGA GEOnet Names Server (GNS)
• NGA is the US military National Geospatial-Intelligence Agency
• It maintains the definitive record of all geographical place names (US version)
– Multi-lingual
– Includes authorised variations
• See http://geonames.nga.mil/gns/html/
– Note use of OGC standards (much more later)
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
NGA GEOnet Names Server
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
The Gazetteer of
Scotland
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Geocoding in OpenStreetMap
• www.openstreetmap.org
• Key components (services) are:
– Map Services (from map databases)
– Geocoding - Gazeteer Services (from the Search
box)
• OpenStreetMap Nominatim
http://wiki.openstreetmap.org/wiki/Search
• GeoNames - http://www.geonames.org/
• A simple user guide can be found here
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Postcodes, http://en.wikipedia.org/wiki/Postal_code
• A postal code (known in various countries as a post code, postcode, or ZIP code) is a series of letters and/or digits appended to a postal addressfor the purpose of sorting mail.
• Germany was the first country to introduce a postal code system, in 1941. The United Kingdomfollowed in 1959 and the United States in 1963. Ireland finally introduced them in July 2015.
• Use of Postcodes has gone far beyond their original purpose– Major use nowadays is for geo-location
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Postcode Geography - UK
• An alphanumeric
code
• A hierarchy
• Nested
– 1,762,464 postcodes
– 10,631 sectors
– 2,971 districts
– 124 areas
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Britain's constitutional hierarchy is
informally reflected in the ordering
of the following three postcodes
• SW1A 0AA – House of Commons (pre-
eminent democratic chamber)
• SW1A 1AA – Buckingham Palace (official
residence of head of state)
• SW1A 2AA – 10 Downing Street (official
residence of head of government)
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
A Scottish Example
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Postcode Geography - UK
• Postcode Address File (PAF) is a data
file available from Royal Mail.
• Every house and business in the United
Kingdom has been given a postal address
by Royal Mail.
• The PAF is a complete collection of over
28 million Royal Mail postal addresses and
UK postcodes
A British muddle finally solved!
• For a long time three entities were at odds over
‘ownership’ and distribution of GB postcode
data:
– The Post Office, owners of the raw IPR
– Local Authorities, responsible for allocating
and maintaining street names and addresses
– Ordnance Survey, responsible for mapping
and ‘framework data’
• In 2011 an agreement was reached, leading to a
J/V company - http://www.geoplace.co.uk
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Roles of GeoPlace
• GeoPlace is a public sector limited liability
partnership between the Local Government
Association and Ordnance Survey
• Centre of excellence for spatial address and
street information management in Great
Britain.
• GeoPlace creates and maintains the National
Address Gazetteer and the National Street
Gazetteer.U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Uses of Postcodes
• insurance premium calculations
– ‘Post Code Lottery’
• as a way to describe United Kingdom
locations to route planning software,
• as the lowest level of aggregation in
census enumeration
• Geographic basis for demographics and
targetted marketing
Nov 2017, land use statistics
• http://www.bbc.co.uk/news/uk-41901294
• Every council area in the UK has been
analysed and individual maps produced
showing how much of the area falls into four
land categories:
– Farmland
– Natural
– Built on
– Green urban
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Digital Globes
Bring multiple sources together to
create a ‘virtual world’
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
‘Digital Globes’• Google Earth:
– Tops in terms of ease of use, user base, earth imagery, supported platforms (Win, Linux, Mac). Not free for business or commercial use.
– https://www.google.co.uk/intl/en_uk/earth/
• Microsoft Virtual Earth (nowadays Bing –essentially only mapping)
– www.bing.com/maps
• NASA Worldwind (no commercial restrictions, easy to ‘embed’ in own apps)
– http://worldwind.arc.nasa.gov/java/
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Google Earth
• A ‘Digital Earth’ on the WWW, displaying
– Map data
– Imagery
– Terrain
– 3D building models
– User-provided content
• photos
– Wikipedia data
– And much more
• Download (free) from www.google.com/earth
How many people are familiar
with Google Earth?• How do you find the user interface?
• What do you use it for?
• Nowadays there are three versions:
– Google Earth Web
• Used from the Chrome Browser
– Google Earth on Mobile
• For use on smartphones
– Google Earth Pro
• Installed on your computer, wider functionality
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
2017 – New Google Earth Web
• Less functionality but works in basic web
browser (no special software to install)
– https://earth.google.com/web/
– NO download neccesary
• Only works on Google Chrome browser
– Desktop or mobile device
• Tutorial here
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Virtual Reality
• More about Google Earth in later sessions
• And a little about Virtual Reality, but this is
really out of scope
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4
Week 2 Weeks
3 & 4
Coming Next!
Reminder – Final Session• Our final session, 16th March 2020, will be given
over to presentations from your good selves.
These can be on any topic, great or small. You
can get the flavour from last year on the
Members Presentations tab.
• Peter Brunning’s presentation on the Everest
marathon includes the .kmz file you can view on
Google Earth, instructions in the other file.
• You might like to start thinking about what you
can contribute (need not be as strenuous as an
Everest Marathon!)U3AC Course ‘Maps in the Computer Age’ – Spring Term 2020, Peter Woodsford – Session 4