Remote Sensing and GIS Questions and Answers

Answer: B

The 'father of GIS' is Roger Tomlinson.

Roger Tomlinson, a British-Canadian geographer, led the development of the Canada Geographic Information System in the 1960s for the Canada Land Inventory, the first computerised GIS, and coined the term 'geographic information system'.

The other names are not associated with founding GIS.

Answer: A

The key's answer is Soil analysis.

GIS (Geographic Information System) layers location data on maps. In agriculture its first and most basic use is soil analysis: mapping soil type, texture, pH and nutrient status across fields so that crops and treatments can be matched to each patch of land.

Honest caution: GIS is also used to map fertilizer needs and to track pest and disease outbreaks, so options B and C describe real uses too, and the question does not say which single one is wanted. The key goes with soil analysis, the standard first application. Speed analysis (option D) is not an agricultural use of GIS, so it is clearly wrong.

Answer: C

From shorter to longer wavelength the order is UV, visible, IR, microwave.

In the electromagnetic spectrum, ultraviolet lies roughly at 10-400 nm, visible light at 400-700 nm, infrared from 700 nm to about 1 mm, and microwaves from about 1 mm to 1 m. So each band in the keyed sequence has a longer wavelength than the one before it (the paper's '\(\gt\)' sign marks the sequence, not a numerical comparison).

The other sequences put the bands out of order: one starts with IR and puts UV after microwaves, another puts microwaves first, and the last puts visible before UV and microwaves before IR.

Answer: A

The term is lineament.

In remote sensing and structural geology a lineament is a mappable linear or curvilinear feature of the landscape, seen on satellite images or aerial photographs, that reflects an underlying structure such as a fault, fracture zone, joint set or dyke. Straight valleys, aligned drainage and tonal lines often mark them, and lineament maps are used in groundwater and mineral exploration.

'Linear' and 'line' are general words, not the technical term. 'Superlineament' is not a standard term; the general definition given in the question is that of the lineament itself.

Answer: C

The system is a GIS, a Geographic Information System.

A GIS is a computer system for capturing, storing, retrieving, analysing and displaying spatially referenced data, so it can overlay layers such as land use, soils and roads and answer questions about where things are and how they relate. The question's wording is the standard definition.

GPS, the Global Positioning System, only determines position using satellites; it collects locations but does not store and analyse spatial data. Landsat is a series of earth observation satellites that supply images. A radiometer is an instrument that measures radiant energy, a sensor rather than a data system.

Answer: C

Remote sensing uses electromagnetic waves.

Remote sensing gathers information about objects without touching them by recording electromagnetic radiation they reflect or emit, in the visible, infrared, thermal and microwave parts of the spectrum. Different surfaces, such as water, vegetation and soil, reflect and emit differently at different wavelengths, their spectral signatures, which lets them be identified.

Sound waves are used in sonar, which is not what remote sensing from aircraft and satellites relies on. 'Electric waves' and 'wind waves' are not the radiation sensed.

Answer: B

Objects on aerial photographs are identified by their Signature.

Every surface reflects and emits energy in its own characteristic way across wavelengths: healthy vegetation reflects strongly in the near infrared, water absorbs it, bare soil rises steadily. This spectral signature, together with tone, texture, shape and pattern, is what an interpreter uses to tell crops, forest, water and buildings apart.

Atmospheric windows are wavelength bands where the atmosphere lets radiation through, and absorption bands are where it does not; both decide which wavelengths a sensor can use, not what an object is. A radiometric error is a distortion in recorded brightness that has to be corrected, the opposite of an identification aid.

Answer: A

Living vegetation appears red.

Healthy leaves reflect near-infrared very strongly because of their internal cell structure. A standard false colour composite displays the near-infrared band as red, the red band as green and the green band as blue, so vigorous vegetation shows bright red, and its intensity indicates its health.

Clear water absorbs near-infrared and appears dark blue to black, bare soil and urban areas appear bluish-grey, and clouds or snow appear white, so the other colours belong to other features.

Answer: B

The region is the atmospheric window.

Atmospheric windows are wavelength bands where gases absorb little, so radiation passes through. The main ones are the visible and near-infrared region and the thermal infrared window at about 8 to 14 µm, through which the Earth radiates to space and which satellite sensors use.

The ozone hole is the springtime thinning of stratospheric ozone over Antarctica. 'Ozone window' is not a standard term, and a black hole is an astronomical object.

Answer: C

The answer is Atmospheric window.

Gases such as water vapour, carbon dioxide and ozone absorb radiation strongly in some wavelength bands. The bands in between, where the atmosphere is nearly transparent, are called atmospheric windows: the visible and near-infrared band, the thermal infrared window around 8-14 micrometres and the microwave region. Remote sensors are designed to work in these windows.

Rayleigh scattering is the scattering of short wavelengths by molecules, which makes the sky blue; it is a loss, not a window. The Raman effect is a change of wavelength in scattered light, and the aurora borealis is light emitted when charged solar particles strike the upper atmosphere near the poles.