Topography

• open jungle: widely spread and scattered trees; moderate rainfall
• pack tract: for cattle or human, shorter distance but inaccessible in rain
• a river has causways when it is non perennial and motorable during dry season
• sheet rocks are well polished, hard and smooth sheek like rock that is exposed to the surface due to the erosion of overlying soil layers and their removal by mechanical weathering.
• open scrub: bushes and scrub found in dry area with annual rainfall less than 100cm
• Falls are waterfalls at the given height; in hilly areas due to sudden and almost vertical drop in the course of the river
• sand features like sand dunes are formed by the continuous action of wind which moves, reshapes and redeposites sand.
• fireline is a broad path which is cleared in a jungle to prevent fire from spreading totother parts of the forest
• if a land is not cultivated check for broken ground, sand dunes and lack of perennial rivers for evidence
• trellised drainage indicates presence of limestones
• for pass on a map, look for a pack tract or a foot path (single broken red line)
• lack of settlement: hilly area, dense forest, no roads or any means of transport
• refractive index is a universally accepted scale with no metric system
• Dep is for depression formed by the action of the wind when it blows away and leaves behind a hollow on the surface of sand forming a depression in a desert
• causeway is a raised road or a track that is build across a seasonal river or swamp that is navigable in dry season
• refractuve index is the ratio of distance of two places on the map to the corresponding actual distance on the earth
• countour interval is the difference of height between two consecutive contour lines on a topographic map
• vertical interval is the vertical distance between any two contour lines
• horizontal equivalent is the actual distance between two points on two contour lines
• gradient is the slope of a land calculated by = V.I./H.E.
• spot heights are approximate height of a point on the ground above the mean sea level in meters
• relative height is the height of a feature with reference to the surrounding land and not relative to the sea level.

  relative depth is the depth of a river or tank with respect to the surrounding lands
• triangulated height is the accurate height of a point above the mean sea level calculated trignometrically
• bench mark abbreviated as BM is the accurate height of a place in meters marked on a stone, pillar or a rock as a permanent reference
• dendritic pattern indicates soft surface rocks or soil material for agriculture
• trellised drainage indictaed alternate presence of hard and soft rocks and limestone indicating instability for agriculture
• dissappearing river indicates dry conditions and sandy solid which is unsuitable for agriculture.
• disappearing rivers are formed when the sandy soil absorbs all water before the stream reaches the main river
• in limestone area, the rivers suddenly disappear through shallow hollows and reappear
• perennial rivers mean good agriculture and well irrigated land
• non perennial show moderate to low rainfall and irrigation is by wells, tanks and canals found
• a town which is at the junction of many routes is usually known as a nodal centre
• a nodal centre has dense settlement with radial pattern of communication
• meandering of river would indicate a flat terrain
• the presence of waterfalls indicates steep gradient
• contours are brown coloured, imaginary lines on the map that connect places of the same height above mean sea level
• the scale of a map denotes the proportion that the distance between any two points on the map bears to the corresponding two points on the surface of earth
• three types of scale: statement, linear and refractive index
• statement scale is expressed in words. it is defined in units
• refractive index is the ratio of the length of a line on a map and that corresponding actual distance on the eart's surface