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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.


  • 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.


  • 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 A topographic map is therefore not always accurate and can even be outdated.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

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
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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