BHU+4120+REMOTE+SENSING+AND+RESOURCES+MANAGEMENT

Introduction – This unit has two sections (a) Remote Sensing – You largely covered this section with Mwalimu Macharia. (b)Aerial Photo Interpretation – this is what you will largely cover with me
 * BHU 4120 REMOTE SENSING AND RESOURCES MANAGEMENT **
 * January – April 2017 Semester **
 * Facilitator : Dr Kennedy Obiero **

NB – With employ two modes (a) F2F – Face to Face lectures (b)On-Line posted materials (BLENDED METHOD OF LEARNING)
 * __ AERIAL PHOTO INTERPRETATION __**

**MOUNT KENYA UNIVERSITY ** **MAIN CAMPUS – THIKA ** **SCHOOL OF SOCIAL SCIENCES ** **Department of Languages and Humanities ** **BHU 4120: REMOTE SENSING & RESOURCES MANAGEMENT **


 * PART B: AERIAL PHOTO INTERPRETATION **

**Aerial photography **is one of the most common and economical forms of remote sensing. It involves taking records (aerial photographs) using a camera (**sensor –** see figure) from an airborne **platform** e.g., a specially modified aircraft, kite, balloon among others. **Types of Aerial Cameras used ** (i) Single-Lens Frame Camera (ii) Multilens Frame Camera (iii) Strip Camera (iv) Panoramic Camera (v) Digital Camera **EXERCISE **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – Read and make notes on the various types of cameras used to obtain aerial photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Air photo –interpretation is a **careful examination of all the elements of a photograph** (ground level/terrestrial, oblique and vertical aerial photography patterns and the deductive and inductive evaluation of the elements as they are observed in the field). <span style="font-family: "Times New Roman","serif"; font-size: 16px;">As in Remote Sensing, information about earth’s surface features is obtained/collected by equipment in the air/space with being in contact with the feature(s). <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The word photography was coined in1839 from two Greek words “phos” meaning light and “graphs” meaning to write or to draw or record. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Photography refers to graphic recording of light energy of different intensities. When aerial is used, it means that photography is conducted from an observation point in the air using a variety of cameras. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The cameras are mounted on a specially modified aircrafts. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Aerial photography can also be done from stationery or mobile airborne vessels such as balloons, kites, aeroplane rockets and satellites. **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Advantages of aerial photography compared to on-the-ground observations ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) Improved vantage point – We see the “big picture” or the whole picture” of the earth surface features (water bodies, rocks, soil types, crop types. These are not easily seen on an on-the-ground observation. You see more from above/air/space. You see a wider area.  <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) Capability to stop action/ – useful in studying dynamic/moving phenomena such as floods, moving wildlife, traffic, forest fires and oil spills.   <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iii) Permanent recording – Aerial photographs are permanent records of phenomena. These can be studies under different conditions. Changes over time can be studied.   <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iv) Broadened spectral sensitivity – Human eye records in the visible part of the electromagnetic spectrum (0.4-0.7 micrometers) while film can record from 0.3 – 0.9 micrometers). Certain phenomena not detected by human eye can be detected in aerial photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(v) Increased spatial resolution – with good camera, film and flight parameters, more spatial details can be recorded than a human eye can do. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vi) Aerial photographs can be taken over very inaccessible or remote areas where there are no roads and other modes of transport. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vii) Quantitative analysis of aerial photographs is possible. Measurements can be carried out and calculations can be done. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(viii) With stereo-viewing of aerial photographs using a stereoscope, more details can be seen than when the naked eye is used. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) **//<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Vertical photographs //**<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – These are photographs taken from the air with the camera axis directed vertically as possible. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- However, a truly vertical photograph is rare due to the nature of altitude that forces aircraft to tilt leading unintended inclination of camera axis – tilted photograph. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- __<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Slightly tilted __<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> photographs are termed as “__vertical__” photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Used for accurate vertical and horizontal measurement of ground surface features.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Types of aerial photographs **


 * Taken with camera axis directed as nearly vertical as possible ||


 * Terrain ||


 * Camera Lens ||

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Appear natural to observer but statistical measurements are difficult to make as scale is large at ht foreground and decreases towards the foreground.
 * //<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) //** **//<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Oblique photographs – //**<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Photographs obtained with the camera optical axis intentionally inclined/tilted.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **//<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Divided into two – //**
 * //<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) //** **//<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Low oblique photograph //**


 * //<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) //** **//<span style="font-family: "Times New Roman","serif"; font-size: 16px;">High Oblique photograph //**

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) The first aerial photograph was taken in France in 1858 by Gaspard from a balloon platform 80 meters above the ground. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) Apart from balloon photography, cameras were also mounted on kites, rockets and pigeons as platforms. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iii) Air photography got revolutionalized with the invention of airplane in 1903 by Wilbur brothers. The first aerial photograph was taken over Italy in 1909 by Wilbur Wright with the aeroplane as a **platform**. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iv) Aerial photography was very useful for military purposes especially during and at the end of World War I. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(v) During 1930 training in aerial photography for other purposes such as agriculture, topographical mapping, planning among others gained momentum. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vi) During the World War II, the demand for aerial photography increased with large areas of France, Italy, Sicily and Egypt being mapped. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vii) With advances in technology, black and while as well as colour aerial photography is now used both for military and civilian use.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Developments in Aerial Photography **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- For aerial photography to naturally take place, energy from the sun is required. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- This energy is in the form of waves. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">-
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Electromagnetic Energy and wave theory **


 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;"> Creast Crest **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The raised part of the wave is the **crest.** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The distance between the crests is known as **wavelength** represented by the Greek letter lambda (**λ).** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The wavelengths can be expressed in metres (m), nanometers or micrometres. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Frequency **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – This is the number of cycles of waves passing through a point. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- In the above wave, the frequency is 3. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- State the frequency of the waves below

<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> Low frequency

<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> Moderate frequency

<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> High frequency

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The shorter the wavelength, the higher the frequency (Showing an inverse relationship between wavelength and frequency). <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The speed of light can be determined from the relationship between frequency and wave length


 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">C = λV **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Where <span style="font-family: "Times New Roman","serif"; font-size: 16px;"> C = Speed of light <span style="font-family: "Times New Roman","serif"; font-size: 16px;"> λ = Wavelength in metres <span style="font-family: "Times New Roman","serif"; font-size: 16px;"> V = Frequency

<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> **__Electromagnetic Spectrum__**

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- In photography and remote sensing, electromagnetic waves are classified according to their wave lengths a term known as **spectrum.**. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Electromagnetic spectrum is a continuum of electromagnetic waves/radiation from the shorter wavelengths (cosmic rays to the longest waver – microwaves, television and radio waves).


 * <span style="font-family: "Times New Roman","serif"; font-size: 13.33px;">UV VISIBLE INFRA-RED MICROWAVE **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">The Visible Spectrum – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">This part of the electromagnetic spectrum in the range between 0.4 and 0.7 micrometers. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- It has **primary colours** blue, green and red.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">0.4-0.5 Blue ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">0.5-0.6 Green ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">0.6-0.7 Red **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The human eye is useful and good sensor in this part of the spectrum <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- We can see rays with wavelengths between 0.4 and 0.7 micrometers. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- We cannot see shorter wavelengths such as UV or longer wavelengths such as infrared, microwave and radiowaves. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The visible spectrum is very small compared to the whole electromagnetic spectrum. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Aerial photography operates in the **UV, Visible and Infra-Red** sections of the electromagnetic spectrum. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Photography can record wavelengths from about 0.3 to 1.2 micrometers (about three times what the human eye can see). <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- To record wavelengths longer than 1.2, other instruments other than the camera are used. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- A photograph is product between the reflected radiation and the film (chemical substance) in the sensor (camera).

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) Aerial photographs are taken with cameras along flight lines/strips. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) The orderly coverage of an area is obtained when the aircraft flies at the same height. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iii) The line traced on the ground directly beneath the aircraft in the process of acquisition is the **nadir line.** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iv) The aircraft has to fly at the same speed in order obtain **60% overlap (forward lap)** of the photograph **(area common on both photographs**). <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vi) This means in any three consecutive photographs, there is usually a **common area** for all of them. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(vii) To obtain coverage for entire area, there has to be a **photo mosaic** done by joining the vertical photographs to form a continuous picture of the ground. Details are obtained from one picture to picture.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Procedure of Obtaining Vertical Aerial Photographs **
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(v) ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">When the plane turns round for the second flight line, parallel to the previous one, the has to be an overlapping area of **20-30% termed as sidelap.**
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(viii) ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;"> This is also known as **flight index mosaic.** Once distortions are corrected the photograph tied to ground control points, a **controlled mosaic is obtained.**





<span style="font-family: "Times New Roman","serif"; font-size: 16px;">The Figure illustrates a forward lap of 60% and an advance of 40%.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Produce black and white (panchromatic) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Coloured photograph using colour film <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- READ MORE
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Production of Photographs using Film (page 74) **

**<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Scale of Aerial Photographs ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) Measure distance between two points on the photograph. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) Measure actual distance between the two points on the ground. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Where <span style="font-family: "Times New Roman","serif"; font-size: 16px;">d = photo distance <span style="font-family: "Times New Roman","serif"; font-size: 16px;">D = ground distance
 * 1) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Like maps, aerial photographs have scale and the amount of details shown on the map depends on the scale.
 * 2) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The scale states that one unit of distance on a photograph represents a specific number of units of actual ground distance.
 * 3) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The scale can be in similar unit equivalent e.g., 1 cm on the map represent 20000 cm on the ground, it can be representative fraction (RF) or ratio scale.
 * 4) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Straight forward method could involve
 * 1) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Scale is then calculated as a ratio
 * 1) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">For vertical photographs from a flat area, scale depends on the focal length (f) of the camera and the flying height (H) of the platform (aircraft) above the ground. The commonest focal length is 152 mm. However, this may be upto 610 (Ogonda, 2004, 1991).


 * 1) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">If the height of the land (h) is known, and the flying of the aircraft (H) is also known, then H can be determined as: H-h.
 * 2) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">A constant scale is only possible on a uniform terrain. However, on a rugged topography or mountainous area, there distortions in scale.
 * 3) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The top of the mountain being near the camera is on a larger scale.
 * 4) <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Scale calculated in such case is only an approximation although degree of accuracy can be ascertained.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) What is the scale of a photo taken with a camera having a focal length of 300mm and at a height of 1500 ft? <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) An aerial camera with a focal length lens of 150 mm was used to shoot photographs of Langata area at a height of 1200m above the ground. Langata is 1400 m above sea level. Calculate the photo scale. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(c) During photo processing, the following marginal information is included on the photo; Fiducial marks, principal point, nadir among others. Explain the significance of marginal information on photographs.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">EXERCISE **

**<span style="font-family: "Times New Roman","serif"; font-size: 16px;">CHARACTERISTICS OF AERIAL PHOTOGRAPHS ** <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- These are the information printed and observed on aerial photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- The information helps in the interpretation of aerial photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- On the first photograph of each run, information provided include: date, flying height above mean sea level, focal length of the lens, time, flight strip number and strip exposure time. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Printed information on aerial photographs/al include: <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Fiducial marks **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – are fine crosses, dots or half arrows or other geometrical marks on the corners or sides of photographs <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- They serve as reference points/marks <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- A line joining opposite sides of the fiducial marks form x-axis and the other perpendicular line using the other fiducial marks is the y-axis. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Principal point **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – It is the centre of the photograph where images are most clear. Usually point of inter-section between x and y axes. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(c) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Other information include **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – strip exposure e.g., 140; focal length reading; altimeter, clock, among others.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) __<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Aerial Photo Interpretation Equipment __<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> (stereoscope) and
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Analysis and Interpretation of Aerial Photographs **
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The basic photo-interpretation equipment id the **stereoscope** useful in viewing photographs in 3-D.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Adjacent pairs of aerial photographs (**stereo-pairs/stereo grams** with a forward lap of 60% are used.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">There are two types of stereoscopes that are **lens** and **mirror** stereoscopes.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The lens stereoscopes are portable and completely cheap.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Consists of two lens mounted on a simple frame supported by short legs.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The spacing of the lens can be adjusted between 45mm and 75 mm to accommodate users’ individual eye spacing.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) __<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Procedure of stereoscopic viewing __ <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) Choose any two overlapping photographs <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) Place a finger on each of the two images on a feature/object common to both photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iii) Move the photographs until the two fingers coincide under the stereoscope. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iv) Remove the fingers and move the photographs slightly to obtain the clearest image possible.
 * **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Stereoscopy – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">This involve a 3D view of any two consecutive vertical photographs (**stereogram/stereo pairs**).
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">To view verticalphotographs stereoscopically,

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Photo-Interpretation proceeds in three stages <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(i) __<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Stage 1 – General Examination __
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Methods of Photo-Interpretation **
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">This is known as detection stage.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Objective is to get the general impression about the area shown on the photograph.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">General relief, drainage, vegetation and cultural features on the photographs are established.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">(ii) __<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Stage 2 – Identification __ <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(a) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Shape **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – General form, configuration or outline of individual objects. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(b) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Size **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – This is considered in the context of the photo scale <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(c) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Pattern **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – Refers to the spatial arrangement of objects e.g., vegetation, rivers, settlements and roads. Think of packing space/drive-in for instance. Spatial arrangement of trees in orchard and forest are different. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(d) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Tone/hue **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">– Considers the relative amount of brightness reflected by an object. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(e) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Texture **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – The frequency of tonal change on photographs. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(f) **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Shadows **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – Linear vertical features such as row of trees, fences and stone walls. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Enhances usefulness of shape in identifying and recognizing features. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(g) **Situation** – Considering the object’s position in relation to others. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Especially features in vicinity. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(h) **Background Information** – Reference to maps and written information of the area. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Background information can help in the identification and recognition of objects.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Involve recognition of individual objects on photographs.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The **basic/fundamental principles of air photo-interpretation** are used which include; shape, size, pattern, tone/hue, texture, shadows, site and association.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">On vertical photographs, object’s height also defines its shape.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Shape of some objects is so distinctive that they are easily identified.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Every shape is of some significance to the photo interpreter.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">The dimension of the needs to be carefully examined in the context of photo scale.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Compare an object of unknown size to some common object(s) of standard dimensions such as a football field.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">On panchromatic film (black and white photograph), the tone varies from black, through grey to white.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Object with a lighter tone means it reflects a lot.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">For soils, tonal variation indicates differences in drainage.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Light tone shows higher and drier areas.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Dark-tones areas are lower and wetter.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Refers to the overall visual “smoothness”/”coarseness” of image features.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Roughness and smoothness of the surface of objects.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Distinguish features with similar reflectance based on their texture.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Consider smooth texture of green grass and rough texture of green trees on air photograph.

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Assigning images on photographs into their respective groups. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- For example, roads – first, second class and third class roads. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Same with residential areas.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">(iii) ** **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Classification Stage **

<span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Land form analysis **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – distribution of landforms e.g., tectonic features, erosional and depositional landforms. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- Features directly observed or by use of stereoscope. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Vegetation types **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> – can be identified for mapping purposes especially in rural areas. Recognize forests, shrubs among others. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Land use analysis **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> and human impact on the environment. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Land cover analysis – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">grass land, arable land, built up area, forest among others. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Rural land use – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> crop types, agricultural activities, forests among others. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Crop types and farming types – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> maize, wheat, grain farming, dairy and beef farming. <span style="font-family: "Times New Roman","serif"; font-size: 16px;">- **<span style="font-family: "Times New Roman","serif"; font-size: 16px;">Urban land use – **<span style="font-family: "Times New Roman","serif"; font-size: 16px;"> towns and cities planned activity zones. Residential, commercial, industrial, transport and open space.
 * <span style="font-family: "Times New Roman","serif"; font-size: 16px;">Application of Aerial Photographs in Geographical Studies **

**<span style="font-family: "Times New Roman","serif"; font-size: 16px;">SECTION B:BREMOTE SENSING **