Geographical Techniques Questions and Answers

Answer: B

The characteristic that separates GIS from other systems is that it links spatial and non-spatial data. A GIS ties a map feature to a record of attributes in a database, so that one can query the data and analyse where things are and what they are like. Map making, generalised output and map design and layout can all be done by computer mapping and drawing systems that have no such link, so they do not separate GIS from other systems. Option B is correct.

Answer: D

The maps in decreasing order of scale are the cadastral map, the topographical map, the wall map and the atlas map, which is (iii), (iv), (ii), (i). Cadastral maps show property boundaries at very large scales, such as 1:4000. Topographical maps are at a medium scale, such as 1:50,000, wall maps are at small scales, and atlas maps are at the smallest.

The other orders put the atlas map or wall map before the large scale maps.

Answer: C

The basin area on the reduced map is 50 sq. cm. The scale is halved, from 1:50,000 to 1:100,000, so every length shrinks to half, and the area shrinks to the square of one half, which is one fourth.

\[ A = 200 \times \left(\tfrac{1}{2}\right)^{2} \]

\[ = 200 \times \tfrac{1}{4} = 50 \text{ sq. cm.} \]

The values 100 and 500 and 1000 come from halving or doubling the area directly, without squaring the ratio.

Answer: B

Lines that indicate water depth on a map are called isobaths. They join places of equal depth below the water surface, and they are used for lakes and seas.

Isogonic lines join places of equal magnetic declination, isopachs join points of equal thickness of a rock layer, and isonephs join places of equal cloud cover.

Answer: B

The shadow is the most expressive element for identifying the Qutab Minar on an aerial photograph. The tower is tall and narrow, and from above it is a small round top, but its long shadow reveals its height and shape clearly.

The shape alone would be a small circle from the vertical view, tone and texture do not distinguish a tower from other objects, so the shadow is the best clue.

Answer: D

The correct matches on standard maps are red for built-up land, dark green for forest area, brown for uncultivable land and yellow for cultivated area, which gives the code iv i ii iii. These are the standard colours used for land use mapping.

The other codes give red to cultivated land or green to uncultivable land, which does not agree with the usual convention.

Answer: D

The topographical map on a scale of 1:50,000 is not a thematic map, option D. A thematic map shows one theme, such as population density, the distribution of minerals or the jute producing areas. A topographical map shows many general features together, such as relief, drainage, settlements and roads, so it is a general reference map and not a thematic one. The other options name places, people or terms that the subject does not connect with this question, so only the keyed option stands.

Answer: B

The key takes the matching a-ii, b-i, c-iii, d-iv, option B. The nearest neighbour statistic Rn is near 0 for a highly clustered pattern, near 1 for a random pattern, and rises to about 2.15 for a uniform one, in which the points are the most evenly spaced. So 0.00 to 0.25 is highly clustered, 0.90 to 1.10 is random, and 1.95 to 2.15 is uniform, and the band of 1.25 to 1.50, between random and uniform, is given as the least dispersed in the list. Options A, C and D pair the bands wrongly.

Answer: B

The key takes option B, 136, as the correct number. The question is about the number of sheets of a map series on the million scale that represent the world, and the key gives 136. The other numbers, 54, 152 and 504, are not the one in the key. A reviewer should note that the stem is worded loosely, and that the answer rests on the key. The other options name places, people or terms that the subject does not connect with this question, so only the keyed option stands.

Answer: C

The correct matching is a-ii, b-i, c-iv, d-iii, option C. The map on the million scale has a contour interval of 500 feet, the one inch map has 50 feet, the quarter inch map has 250 feet, and the half inch map has 100 feet. Options A, B and D give at least two of the scales the wrong intervals. Each row is checked against the four codes in turn, since a single wrongly paired item rules a code out and only one code is right for all four rows.