Eighteen integrated geography cases

Use these cases after the chapter lessons. For each one, identify the evidence, perform the requested reasoning, then state one limitation. Numerical examples are hypothetical unless explicitly dated and sourced.

Case 1 — Scale, distance and time

A 1:200,000 map shows a road segment 4.2 cm long. A town lies 7.5° east of a reference meridian. Calculate the mapped ground distance and approximate local-solar-time difference.

Worked answer. One centimetre represents 200,000 cm, or 2 km; 4.2 cm represents 8.4 km. Longitude changes local solar time by about four minutes per degree, so 7.5° corresponds to 30 minutes. The eastern place is ahead in local solar time. Do not use this to alter India's civil clock: IST is a national convention. If the map image was resized, check a scale bar before measuring.

Case 2 — From rock to plateau relief

A field note describes stacked basalt layers, a steep plateau edge and a valley cut through weaker material. Explain the likely relationship among rock, relief and drainage.

Worked answer. Basaltic lava flows can form resistant layers over a broad surface. Differential erosion may leave scarps while streams exploit joints or weaker zones and incise valleys. Weathering contributes soil material, but soil depth and drainage depend on slope, climate and time. The description supports a broad geological interpretation; it does not identify an ore reserve or prove the field belongs to a single uniform soil region.

Case 3 — Six-region comparison

An exam map marks the Himalaya, a low alluvial belt, the Deccan, a northwest arid region, two coasts and island groups. Name the six divisions and one process linking them.

Worked answer. The six broad divisions are the Himalayan Mountains, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains and Islands. Rivers link several: erosion in highlands supplies sediment to plains and coastal deltas. Relief and climate create opportunities and hazards, but no division is internally uniform. A national map is suitable for broad location, not village-level soil or flood assessment.

Case 4 — Mountain road after heavy rain

A steep Himalayan road is cut into a weathered slope. Intense rain is forecast and a small stream crosses the route. List the main risk chain and the evidence needed for a decision.

Worked answer. Rain can saturate susceptible material, raise pore pressure and trigger a slide; debris can block the stream, while runoff may damage the road. Risk depends on slope geology, drainage, cut geometry, rainfall intensity, traffic and exposure. A current IMD forecast, local slope/road monitoring and district administration advisory are needed. The book's cross-section is not a site-safety certificate.

Case 5 — Floodplain settlement

A settlement occupies a slightly raised strip beside a river, with lower fields beyond it. The strip is called a natural levee. What does this imply and what does it not prove?

Worked answer. Overbank floods can deposit coarser sediment close to a channel and build a raised natural levee. The lower flood basin may inundate more often, but the levee is not an engineered embankment and the label does not establish flood recurrence or safety. Current elevation, gauge records, channel history, drainage and official warnings are needed for planning.

Case 6 — Coast-to-plateau transect

Moist monsoon air moves inland from the Arabian Sea across the Western Ghats. Explain a possible rainfall contrast and identify one exception.

Worked answer. Forced uplift can produce heavier rain on windward slopes. After crossing the highlands, descending air may be drier and some interior areas can lie in a rain shadow. Valleys, passes, season and circulation create exceptions; local rain is not determined by one mountain line. Use dated IMD observations or normals to quantify a location, and forecasts for near-term decisions.

Case 7 — Tributary, distributary and basin

On a river map, a smaller channel joins the main river upstream, while another channel branches away near the mouth. Identify them and explain why direction matters.

Worked answer. The joining stream is a tributary; the branching channel is a distributary, often associated with delta networks. A drainage divide separates runoff to different basins. Left and right banks are named while looking downstream. A line on a small-scale map may omit minor streams; absence from the map does not prove absence on the ground.

Case 8 — Peninsular river identification

River A rises near the Western Ghats and flows east through a large basin to the Bay of Bengal. River B flows west in a valley between central highlands. Which broad systems fit the clues?

Worked answer. River A could fit the Godavari, Krishna, Mahanadi or Kaveri pattern; tributaries and source location are needed to identify which one. River B is consistent with the Narmada. Direction alone is not enough. Trace outlet, course, tributaries and relief, and avoid using an undated map for current water allocation or reservoir status.

Case 9 — Normal versus observed rain

IMD's all-India annual rainfall normal for 1971–2020 is 868.6 mm. A local station records 1,020 mm in one year. Can the station be called 17.4% above normal?

Worked answer. Not from the all-India normal alone. The station needs its own comparable reference normal. The arithmetic difference from the all-India value is 151.4 mm, about 17.4%, but that comparison mixes a local observation with a national spatial average and is not a valid station anomaly. State the spatial unit and period before calculating.

Case 10 — Cyclone forecast cone

A forecast map places a coastal district within the uncertainty cone, while the centreline passes offshore. What should residents infer?

Worked answer. The cone expresses uncertainty in the predicted storm-centre track under the product's method; it is not a uniform-impact zone. Wind, rain and surge can extend beyond the centreline or cone. Residents should follow the latest IMD bulletin and local administration instructions. A historic track or this teaching sketch cannot guide evacuation today.

Case 11 — Soil and irrigation

Two basalt-derived fields have different slopes. One is deep and gently sloping; the other is shallow and steep. The first is irrigated heavily but poorly drained. Explain the likely differences.

Worked answer. Parent material is similar, but slope and drainage create different soil depth and erosion risk. The shallow slope may lose soil rapidly without cover. Heavy irrigation on the deeper field can cause waterlogging or salt accumulation if drainage is inadequate. Field testing, water quality, crop stage and management history are needed; the broad soil label is only a starting point.

Case 12 — Forest statistic check

A headline says forest area increased. What questions should a candidate ask before accepting the claim?

Worked answer. Ask which report year, whether the number is recorded forest area, canopy-based forest cover or tree cover, what threshold and method were applied, and what land types were included. Net area can hide fragmentation, species change or degradation. Compare the same definition and time series. FSI's 2023 report is a dated assessment, not a live inventory.

Case 13 — Production, area and yield

Crop output rises 8% while reported area rises 5%. Is yield up 3%?

Worked answer. Not exactly. If production and area definitions align, yield is production divided by area. The yield change is approximately (1.08/1.05)-1, or 2.86%, not a simple 3 percentage-point subtraction. Confirm the same crop year, estimate status, geographic area and revision basis. Output and yield do not directly measure farm income.

Case 14 — Mineral occurrence versus production

A map marks a coal-bearing basin; a table reports production from a nearby district. Does this establish an active mine at the mapped point?

Worked answer. No. A geological basin, a resource estimate, a reserve, a lease, an operating mine and annual production are different spatial/statistical categories. Check the table's reporting unit and year and the responsible mining records for operational status. A broad map can locate a province but not verify a current mine boundary.

Case 15 — Port hinterland

An inland agricultural cluster is 150 km from a port by road but 310 km from a rail-connected port. Which is the better export route?

Worked answer. Distance alone cannot answer. Compare travel time reliability, cargo type, handling, cold-chain needs, road/rail transfers, port service, congestion, cost and return loads. Perishables may value speed and refrigeration; bulk cargo may benefit from rail. A current logistics study is required to determine the least-cost route.

Case 16 — Density and net migration

A district has 2.4 million people over 12,000 km². During a period 40,000 people arrive and 35,000 leave. Calculate density and net migration.

Worked answer. Arithmetic density is 2,400,000 ÷ 12,000 = 200 people per km². Net in-migration is 40,000 − 35,000 = 5,000. Gross movements total 75,000, so the small net balance does not mean little migration. The density average hides within-district variation.

Case 17 — Andhra Pradesh delta and interior

A coastal district reports flood exposure after a cyclone, while an interior district faces water stress. Is this contradictory for one state?

Worked answer. No. Coastal deltas can combine low elevation, river floods, rainfall and storm surge. Interior water availability depends on local rainfall, basin access, storage, groundwater and demand. Different regions and seasons can face contrasting risks. Use APSSDI layers and current official warnings for operational decisions; a regional locator cannot assess a village's exposure.

Case 18 — Multi-layer evidence audit

A student combines a rainfall normal, crop-production table, resource map and highway line to claim that a district will become an industrial food-export hub next year. What evidence is missing?

Worked answer. The claim overreaches. A normal is not a forecast; production is not exportable surplus; a resource map is not an operating facility; a highway line is not a logistics assessment. The student needs dated crop-year data, storage and processing capacity, land/water availability, market and port access, environmental approvals, investment and project status. Each source must answer one stated part of the claim.