The Declination Diagram on Topographic Maps

The Early maps usually had an arrow indicating to the north direction. By showing the north direction, it is easy for the map user to identify other important directions like west, east and south.

Map Projections: The meaning and examples

Map projection is a technique of flattening the spherical surface of the earth into a 2D map surface. Since the earth is spherical, it is impossible to flatten it out perfectly without causing some distortions to either its shape, distance, size or direction.

Difference between Index, Intermediate and Supplementary Contour lines

Sometimes a map may have several contour lines such that it becomes difficult for the cartographer to label the elevations of each contour line. Thus, in order to make the map easier to read and less cumbersome, every fifth (5th) contour line from the mean sea level is usually labelled with its elevation and sometimes bolded a little bit heavier than the rest. These bolded and labeled contour lines are usually referred to as the index contour lines.

How to Identify the type and nature of the underlying bedrock on a topographic map

 Geological information is not directly indicated on topographic maps. It can, however, be identified through a thorough analysis of the relationship between various geographical aspects.
In topographic map, factors that can help to determine the type and nature of the underlying bedrock of an area include, but are not limited to, the following;

Contour lines on topographic maps

Contour lines are the lines drawn on the map connecting all points on the earth’s surface with equal elevations above a fixed datum line (usually the mean sea level).
The act of using contour lines in order to represent the relief of an area on the map is known as contouring. Contouring is the most common method of showing relief on topographic maps because it has the ability to show all five (5) aspects of relief (shape, orientation, size, elevation and slope) on the map.

Recognizing drainage patterns on topographic maps

A drainage pattern, also known as a river system, is a pattern achieved by a network of river channels and tributaries in a particular drainage basin. The topography of the land and the underlying geology have a great impact on the drainage patterns of rivers. On topographic maps, drainage patterns can be identified by the shape/pattern made by the main river and its tributaries.
Some of the common drainage patterns include:

How to recognize and describe water features on topographic maps.

Water features can be either natural or human-built. Natural water features can include oceans, seas, lakes, swamps, rivers, waterfalls, rapids, estuaries, waterholes, boreholes, wells, and springs, whereas human-built water features include water tanks, canals, dams and cattle dips.

On topographic maps, water features are usually indicated by conventional symbols, as shown in the figure below. 

How to recognize and describe vegetation on topographic maps.

Vegetation can be natural or human-planted. Natural vegetation includes forests, thickets, woodlands, grasslands, scrubs, scattered trees, riverine trees, swamp, marshes, etc., whereas human-planted vegetation includes plantations, human-planted forests, etc. It is important to look for any sign that might indicate whether the vegetation type shown on the map is natural or not, before describing vegetation.

The difference between 'Elevation' and 'Depth'

Both the terms ‘elevation’ and ‘depth’ describe the vertical position of points on the earth’s surface as measured from the mean sea level. However, the term elevation is mainly used when referring to points above the sea level, and depth is used for points below the surface

What does “RELIEF” mean in Geography?

The relief (also known as terrain ) of an area is the physical configuration or appearance of the land surface in terms of shape, orientation, size, elevation, and slope.

The earth’s surface is made up of various natural features such as water bodies, vegetation, landforms, rocks, etc. For any natural feature to be considered a relief feature, it must satisfy the five conditions, known by the mnemonic of ‘SOSES’.

How To Determine And Interpret The Gradient Of A Slope On Topographic Maps.

Slopes represent the rising or falling of the land surface. Slopes can either be gentle or steep.  The slope is said to be steep when the land surface is rising/falling sharply and said to be gentle when the rising/falling of the land surface is mild.
A gradient is usually used to measure how steep or how gentle the slope is. In other words, it measures the rate at which the slope is rising/falling. However, due to the fact that the surface of the land is rarely uniform, gradient measures the average steepness of the slope of a piece of land.

A gradient is basically the average rate at which the ground slopes.
With the help of contours, the gradient of a given slope or a terrain feature can be conveniently determined from a topographic map. This article will show you how to determine gradient from a topographic map, how to express it and, how to interpret it.

Methods of Representing Relief of the Landscape on Topographic Maps

Relief of a landscape is basically the physical configuration or appearance of such a landscape taking into account the elevations, slopes, and shape of natural features found in it.
On maps, cartographers usually use several methods to portray the relief of the terrain. These include; contouring, layer tinting, relief shading, hachuring, benchmarks, trigonometric points, and spot heights. Which method is used on a certain map is usually the choice of the cartographer and a single map can contain more than one of these methods.
This article describes each of these methods in detail.

Difference between Altitude and Elevation

Altitude and elevation are two terms widely used in day to day lives. These two terms can be easily confused with each other since they both describe how high a point or an object is, from a certain a reference point or level. In most cases, the reference point is the mean sea level.
Despite the similarity, these terms are completely different and also used in completely different fields of study. Therefore, it is very important to understand the difference between altitude and elevation.

Marginal Information of Topographic Maps

A map could be compared to any piece of equipment, in that before it is placed into operation the user must read the instructions. The most logical place to begin when reading a map is the marginal information and conventional symbols, where useful information telling about the map is located and explained. All maps are not the same in terms of layout and information, so it becomes necessary every time a different map is used to examine the marginal information carefully.

Printed around the border or margin of the map are the information and additional facts about the specific map sheet that a given user is reading. This is referred to as Marginal Information. They are the basic components of a map since they give supportive details to make a map well defined and understood.


Marginal information found in topographic maps include the following;

GLOSSARY

Here is a list of all the geographic terms and vocabularies used in this blog, with their corresponding definitions.