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