Aerial photos

 

Aerial photos

These are photos taken from above by a camera mounted on a flying object such as a helicopter, aero plane, drone etc.

They help us to understand what the area looks like from top.

 

There are two types of aerial photographs

1.     Vertical photos

2.     Oblique photos

 

Uses of aerial photos

1.     Show vegetation more clearly than maps

2.     Identify crop patterns

3.     Observe traffic congestions

4.     Identify pollution

 

Vertical aerial photos

These photos are taken directly from above the area of interest.

That is they are taken when the flying object with the camera is directly overhead and the picture is taken at right angles to the ground from above.

 

Since they are taken directly from above at 90⁰, they are similar to maps!

 

 

Vertical aerial photos

 

 

Uses of vertical photos

1.     Often used in making topographic maps (maps showing the terrain with surface features)

2.     For spying

3.     For certain legal requirements like property  conveyancing

4.     For township and land use planning

 

Advantages of vertical photos over maps

1.     Can be  readily obtained

2.     Gives the current view of the ground

3.     Can be produced within a much shorter time.

 

Disadvantages

1.     Do not show the relief of the ground features

2.     Could be difficult to identify certain ground features

Oblique aerial photos

Fig.3 shows an aerial photo being taken at an angle from above.

This produces an oblique photo of the area like the one shown in Fig.4.

Note that you can see some sides of the features (like walls and tree trunks facing the camera) in addition to tops.

 

Advantages of oblique photos

1.     Can be taken from  a desirable angle

2.     Shows the relief of the ground features clearly

3.     Easier to interpret than vertical photos

 

Disadvantages

1.     The photographer should be a trained person