The Earth and their Projection on Maps Aerial Photos and rectified Ortho-Photos Topographical Maps, Urban plans Degree (Lat/long), UTM-Grids on Topo-Maps Use of Handheld GPS Equipment (Garmin 72, Garmin 76 or Garmin Venture Etrex) Data Transfer to Office Computer GIS-Reproduction and Appearance on digital Topo- Maps and Plans Handle of GPS and GIS with Topo-and Orthophoto Maps a Practical Introduction
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The Earth and their Projection on MapsAerial Photos and rectified Ortho-PhotosTopographical Maps, Urban plansDegree (Lat/long), UTM-Grids on Topo-MapsUse of Handheld GPS Equipment (Garmin 72, Garmin 76 or Garmin Venture Etrex)Data Transfer to Office ComputerGIS-Reproduction and Appearance on digital Topo-Maps and Plans
Handle of GPS and GIS with Topo-and Orthophoto Maps a Practical Introduction
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 2
Content of the training
1. Objectives and Timing of the training2. General Introduction to Topographical
Maps and Orthographical Photos3. Grids of the Earth4. Position and Measurements on maps5. Introduction to GPS Equipment6. Handling of Handheld GPS7. GPS - Data collection and storage8. GPS- Data Transfer to GIS (ArcView)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 3
Schedule of the training (1)1. Afternoon: 13:00 to 16:302. Please be prepared to work in the field tomorrow
for some hours3. Please ask questions if you could not understand
what I am teaching or explaining ! - This is very important !
4. Please don’t be afraid to ask me questions !5. I have to express my deep thanks to RUA,
especially to H.E. our Rector who organized and supports this training together with the graduate school.
6. I wish us all a successful and fruitful training this week at RUA
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 4
Objectives of the training (1)1. Practical training on handling of
Global positioning system measurements (GPS)
2. Basic Information about Topographical Maps and Orthographical Photos
3. Transmission and teaching of general information about GPS
4. Opportunities and Facilities of handheld GPS5. Practical GPS measurements in the field in
relation to field survey tasks6. Transfer GPS-Data to Desktop-GIS (ArcView)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 5
Topo- and Orthographic Maps - Intro (2)
1. What is a location in general ?2. What is a topographical map ?3. Which scales of Topo-Maps you know ?4. What you can find on a Topo-Map ?5. What is an Orthographical Photo6. Which scales of Orthophotos you know ?7. What you can see on Orthophotos ?8. How you can acquire Aerial Photos ?9. How you can produce Orthophotos ?10. What is an appropriate planning scale ?
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 6
What is a location in general ? (1)
Location only makes sense when the location is compared to some frame of reference. Relative location: Guesthouse Hy Hengly- # 67 E o2
right to the beauty salon
Absolute location:- 40 P 0492004; 1276629 (UTM)- N 11°32’54,6“ / E 104° 55‘’36,0“ (Lat Lon)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 7
The relative location (1)Relative location:Guesthouse Hy Hengly- # 67 E o2 - right to the beauty salonWhy this is a relative location ?
Because this adress might exist in several cities in Cambodia. Their is a some uncertainty, still !
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 8
The absolute location (1)
Northpole
Greenwich, UKZero-Meridian
orPrime Meridian= 0°Longitude
Equator= 0° Latitude
Absolute location= W 92° 24‘’56.4“
Longitudeand North
34° 26’21.6“
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 9
What is a map in general ? (2)
A map is a graphic representation of selected geographic features represented on a plane surface
Maps are essentially models of the Earth’s surface
Maps always have limitations - they are never completely accurate, and they are always incomplete
Maps may misrepresent information or deceive the user (either deliberately or accidentally)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 10
1. What is a topographical map?(2)
A Topographical map is…
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 11
2. Which scales of Topo-Maps you know ? (2)
Topographical maps in Cambodia are produced in following scales:
1. 1: old French Maps 1954
2. 1: old French Maps 1954
3. 1: new Min Transport 98 / 02
4. 1: new Min Transport 98 / 02
5. 1: Dep. of Geography
6. 1: Dep. of Geography
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 12
3. What you can find on a Topo-Map ? (2)
On Topographical maps you can find:1. B… A…. Str…2. R… L… Cha…3. R… T… Ra…4. I… L…5. L… O…6. Ma… Bui…7. Isoh…8. G… Geod.. P…
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 13
4. What is an Orthographical Photo ? (2)
An Orthographical Photo is a…
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 14
5. Which scales of Orthophotos you know ?(2)
Orthographical Photos are produced in following scales:
1. 1:
2. 1:
3. 1:
4. 1:
5. 1:
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 15
6. What you can see on Orthophotos ? (2)
On Orthographical Photos you can see the following objects:
1. R…
2. R…
3. Ra…
4. H… Bui…
5. L… Oc…
6. In… L…
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 16
7. How you can acquire Aerial Photos ? (2)
Aerial Photos (orthographic) can be acquired by using:
1. Metric Analogue cameras on small planes
2. Satellite borne digital camera
3. Pilot less small automatic planes
4. Small aerial balloons like hydrogen balloons
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 17
8. How you can produce Orthophotos ? (2)
Orthographical Photos can be produced using several techniques:
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 18
9. What is the appropriate planning scale ? (2)
The appropriate planning scale depend on the objective, the objects and the available scale of the base data.
That means, that you can not easily up- or down scale your data until it fits to the required scale.
Try to avoid down scaling of base data or maps, i.e. from 1: 25.000 to 1: 10.000.
You can up scale or generalize or your data as much as you like but with generalization you will loose information of the data.
An appropriate planning scale for urban environment is between 1: 1.000 to 1: 15.000.
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 19
Exact position measurementon Topo-Maps
Warming up Exercises with Topo-Maps
1. Bridge Nat. Road
2. AirportEntrance
3. Minorcrossroads
4. RailroadBridge
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 20
Warming up Exercises with Orthophotos
1. Major CrossroadsCentral Place
4. MinorBridge
Exact position measurementon Ortho-Photo
2. Minor Crossroads
3. NE–Cornerof building
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 21
The Earth is round? - Grids of the Earth (3)
Equatorial Diameter=12,758 km (7,927 mi.)
Polar Diameter=12,714 km (7,900 mi.)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 22
Why do we need an ellipsoid?
European Remote Sensing satellite, ERS-1 from 780Km
This image depicts the earth’s shape without water and clouds. It looks like a sloppily peeled potato, not a smoothly shaped ellipsoid.
Calculation of geographic position on this irregular surface is very complex. Therefore a much simpler model is needed.This simplified mathematical surface is an
ellipsoid.
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 23
What is an ellipsoid
Semi-major Axis: a = 6371837 mSemi-minor Axis: b = 6356752.3142Flattening Ratio: f=(a-b)/a = 1/298.257223563
Rotate Ellipse in 3Dimensions:
a
b
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 24
Traditional Horizontal DatumsThe Traditional Approach
Many nations established their own regional datum.Used various national standards and procedures
Different time framesCalculated ellipsoids that fit well locally
Established initial point location and orientation with astronomic observations
Result: Inconsistent Datums
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 25
How to measure on a round Earth ? (3)
To measure a position on an approximately round object you can use only round parts of a circle that we call Arcs.The crossing of two arcs creates an exact position on the round earth, that is measurable in Degrees, Minutes and Seconds.
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 26
How to measure on a round Earth ? (3)
Measurement to know !
1 Degree Latitude ~111 km
1 Degree Longitude~111 km at Equator
and up to0 km at Poles= longitude convergence
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 27
What is a Grid ? (3)
A Grid is set of intersecting lines that allow position to be specified exactly at the crossings and also in-between the crossings
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 28
What is a Grid ? 2-Dimension (3)
Alphanumeric Grid
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 29
What is Cartesian Coordinate System (3)A three dimensional GRID Three dimensional right hand coordinate
system with an origin at the center of the earth and the X axis oriented at at the Prime Meridian and the Z at the North Pole
• X Axis Coordinate Distance from the Y-Z plane measured parallel to the X-Axis;positive from90º W Long to 90º E Long
• Y Axis Coordinate Perpendicular distancefrom the plane of the prime meridian; positive in the eastern hemisphere and negative in the western.
• Z Axis Coordinate Perpendicular distance from the plane of the equator; positive in the northern Hemispherenegative in the southern Hemisphere
X0º Long
Z
Y90°E
Prime Meridian
(X,Y,Z)
Equator
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 30
Geographic CoordinatesLatitude, Longitude, & Ellipsoidal HeightLatitude & Longitude are defined by the Prime
Meridian and the Equatorial reference planes
Geographic latitude Vertical angle fromthe equator to the normal of ellipsoid, positive in Northern Hemisphere andnegative in the southern
Geographic longitude Horizontal angle from the prime meridian positive in the eastern hemisphereand negative in the western
Geodetic height Distance normalfrom the reference ellipsoid
Observer’sMeridian
PrimeMeridian
Latitude
Longitude
Y
Z
XLat- lonN 11°32’54,6“E 104° 55‘’36,0“
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 31
Grids of the Earth (3) How to measure on an
approximately round body ?
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 32
Datum definition and location
A datum defines the initial point and reference
surface
A coordinate system determines how
locations are referenced from the
datum
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 33
NAD 27(Clarke Ellipsoid )
ED 50(International Ellipsoid)
Datum definition and locationLimitations to the different Datum Approach
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 34
Regional vs. Global Datum Approach
Global replaces regional datum with a common, accurate standardOne system for maps of the entire planet
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 35
WGS 84
North American DatumClarke 1866
South American DatumInternational Arc Datum
Clarke 1880
EuropeanDatum International WGS72 Datum
TokyoDatumBessel
Most widely used local Datum/Ellipsoid pairs
Indian 54 DatumIndian 60 Indian Thailand
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 36
Datum definition: Location in Cambodia
A coordinate system determines how
locations are referenced from the
datum
Definition of Indian 60 Grid Datum
Dx = 198Dy = 881Dz = 317dA = 861dF = 0,0000284
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 37
Rules of Thumb for Latitude Longitude
Rules of thumb for latitude• 1º Degree latitude ≅ 60 nautical miles (≅ 111km)
• 1’ Minute latitude ≅ 1 nautical mile (1853 m)
• 1” Second latitude ≅ 30 meters
• 0.1” 1/10 second latitude ≅ 3 meters
• 0.01” 1/100 second latitude ≅ 30 centimeters
Rules of thumb for longitude• Don’t forget longitude convergence
• Don’t forget the base 60 conversion
• 60 minutes per degree
• 60 seconds per minute
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 38
Grids of the Earth (3)
1. Lines of latitude are always parallel.
2. Lines of latitude are evenly-spaced.
3. Meridians of longitude converge at the Poles.
4. Meridians and parallels always cross at right angles.
Try to maintain these properties on paper.
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 39
… so, how to get it flat ? - Projections (3)
Map projections are used to transfer and project data from the round earth onto a flat peace of paper. There are several different kind of map projections.
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 40
Planar Projections (3)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 41
Cylindrical Projections (3)
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 42
Projection Properties (3)
Shape: Maps that maintain true shape are called conformal (e.g. Mercator)
Like:UTMUniversTransversMercatorProjection
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 43
• Projecting the sphere onto a cylinder tangent to a central meridian.
• Distortion of scale, distance, direction and area increase away from the central meridian.
• If you rotate the cylinder every 6º of longitude you create the UTM projection.
• This projection is used on map scales of 1:500,000 and larger
UTM-Projection
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 44
Universal Tranverse MercatorThe UTM graticule coverage in belt No 1 -60
Each belt is 6O in longitude wide
1 30 60180o 180o0o
84o N
80o S
Equator 0 meters N10,000,000m N
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 45
Cylindrical Projections (3)UTM Projection and Coordinates:• Flat Grid extending from 84N to 80S• Each zone is numbered Eastward starting at 177°W (6°
wide from 180°W to 174°W)• Coordinates are read east then north• Many map products from foreign countries use UTMs
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 46
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 47
How many UTM Zones in total ?
Which Zone(s) for Cambodia ?
If we are on Position UTM ….0491150 1280495:
How far is the Central Meridiane of our Zone ?
In which Direction is the Central Meridian ?
UTM-Projection - Questions:
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 48
Projection Properties (3)ConformalShapes are maintained on the map as they are on the globe. Angles are preserved
Equal AreaMaps cannot simultaneously show shape and area accurately. Area of all features on the map have the same relative proportions and size as they do on the globe.
EquidistantScale stays the same across the entire map sheet.
So equal-area maps show only area accurately and conformal maps show only the shape accurately. Compromise Maps: Show neither area nor shape completely accurately
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 49
Warming up Exercises with maps
Please find Locations on the MapDetermine UTM Coordinates from theMap of the following points
on your Topographical Mapof Battam Bang City
as well as later
on your Orthographical Aerial Photo of Battam Bang City
8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 50
Global Positioning System (GPS)
GarminEtrex VentureHandheld Outdoor 12 Band Reciever
Garmin GPS 72Handheld Personal Navigator 12 Band Reciever
Next lesson>Introduction to handle two different handheld GPS – ReceiverGarmin 72 and Garmin eTrex Venture