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Social sciences: geography

Grade 7

Map work

Module 11

Reading, analysing and interpreting vertical aerial photos and orthophoto maps

  • Before it can be expected of you to interpret vertical aerial photos and orthophoto’s any further, you will need more information.

A vertical aerial photo of a specific area is taken vertically from above from an aeroplane.

Advantages

  • Most objects are visible.
  • The layout of roads and railway tracks are clearly visible.
  • High trees, mountains and buildings can easily be distinguished by their shadows.

Disadvantages

  • The photos are as seen from above and the view is therefore odd to man. It is an unusual visual angle and one needs a lot of practice, knowledge and experience to read it.
  • It is in black and white and can be confusing.
  • Vertical aerial photos are used as the basis when topographic maps are drawn. Information from the aerial photos is transferred by cartographers (people trained to draw accurate maps) on paper by using the international symbol key and colours, which you are familiar with.
  • Today orthophoto maps are very popular in map studies. The advantages of the 1:50 000 topographic map and vertical aerial photo are combined to draw an orthophoto map. An orthophoto map is therefore a vertical aerial photo on a lower level of 1:10 000, with contour lines added.
  • Contour lines of 5 metres intervals are used in order to identify detail. Even names of places, railway lines and roads are shown on the photo. The objects are therefore easily identifiable. Maps and photos therefore have there own characteristics, advantages and disadvantages. A clear presentation of a landscape is actually only possible when using a topographic map and photo together.
  • A topographic map is the presentation of the surface of an area on scale, using a symbol key. This provides a simplified picture on which only certain characteristics are shown. A topographic map is therefore not always accurate and can even be outdated.
  • A vertical aerial photo and orthophoto map are very useful tools when used together with a topographic map. Only then accurate map and photo readings can be made.

1. How do you study or interpret a vertical aerial photo or orthophoto maps?

  • Size of objects

If the scale of the photo is calculated, then the length of objects can be determined and the distance and square area can be calculated. This method is used to determine the area of an urban settlement with a grid pattern.

  • Shapes of objects
  • Man made phenomena are generally evenly distributed. Here you can consider the shape of buildings, ploughed lands, roads, railway lines and dam walls. Natural phenomena and objects are evenly distributed, like mountains, rivers, forests, and grasslands.
  • Roads are broad grey lines on a photo. National roads are usually straight with no sharp curves. Secondary roads appear narrower and have many curves. Railway lines appear as small dark grey lines with gradual curves. Roads often have perpendicular connections with other roads, whereas railway lines gradually connect up with other lines.
  • Rivers are wide and dark grey lines with curves and bends where they meander through different areas, and other side streams connect up with the main stream. The V-shape of a side stream connection will ALWAYS point down stream and can be used to determine the direction of flow.
  • The tint and shading of objects

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Geography grade 7. OpenStax CNX. Sep 09, 2009 Download for free at http://cnx.org/content/col11021/1.1
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