Geography 12: Mapping Skills

UNIT 2October 9th, 2011

Let's look at our first topic under Mapping Skills - Contour Lines.

Objective

A contour line on a map is a line that joins points of equal elevation.

Contour Lines

The contour line represented by the shoreline separates areas that have elevations above sea level from those that have elevations below sea level

Contour Lines

Lets review the basics of Latitude and Longitude

Objective

(shown as a horizontal line) is the angular distance, in degrees, minutes, and seconds of a point north or south of the Equator. Lines of latitude are often referred to as parallels.

Latitdude

Degrees latitude are numbered from 0° to 90° north and south

Each degree of latitude is about 69 miles (111 km) apart

Latitude

(shown as a vertical line) is the angular distance, in degrees, minutes, and seconds, of a point east or west of the Prime (Greenwich) Meridian. Lines of longitude are often referred to as meridians

Longitude

The degrees continue 180° east and 180° west where they meet and form the International Date Line in the Pacific Ocea

Longitude

To precisely locate points on the earth's surface, degrees longitude and latitude have been divided into minutes (') and seconds

Longitude and Latitude

Scale A map represents some portion of the earth or sky on a two dimensional surface. The size of the individual features need not be indicated if a map scale is given

Objective

two dimensional feature of the earth’s surface.

eg road map, city plan, drainage network map, map showing political boundaries

Planimetric Map

shows three dimensional features of the earth’s surface, that is, the relief or topography of the land surface or ocean floor through the use of contour lines

Topographic map

Map scale expresses the relationship(ratio) between distance on the map and the true distance on the ground (In reality)

Every Map should have its scale clearly indicated

Ex: 1:90000

Scale

Geography 12: Mapping Skills

Lesson 2: October 22, 2010

According my source in BC there would be no reason to use a calculator on the Geography Provincial exam

Review Homework Scale Gradient Military Grid and Map Symbols Topographic map Interpretation Air Photo Interpretation

Today’s Class

Let's look at how to calculate gradient which is a measurement of the steepness of the land or simply slope

Gradient

A method to locate points on a map.

With this method, a system of numbered lines is superimposed on a map and position is stated by quoting the numbers of the lines that intersect at the point in question.

Military Grid

Symbols on a topographic map

Let's look at some basic guidelines to assist you in interpreting an air photograph

Air Photo Interpretation

Shape Cultural features: - some features such as airport runways have a distinctive shape which make them easy to identify

Natural features-- quite easy to tell the difference, for example, between an orchard (rows of trees with regular spacing) and a forest area with irregular tree growth

Feature Identification

formed by the repetition of a featureeg farm fields, rows of trees in an orchard, oil storage tanks at a refinery

Pattern

- high objects such as towers, chimneys, bridges, or high buildings cast shadows which help you to identify the object

Shadow

Cultural Features - roads and tracks will usually

have a light grey tone as they are fairly reflective of light- railways: medium grey- bridges: vary according to construction material

Tone

Natural Features Water

- generally appears dark grey or black since it absorbs much of the light

Tone

Vegetation - most will vary from shades of grey to black

Tone

Soil- bare ground usually has a light colour but the wetter it is, the darker the tone

Tone

Crops- cultivated fields and fallow fields are almost white in tone

Tone

General GuideSpring: sharp, distinct field patterns due to differences in tillage and crop developmentSummer: dark tones for maturing crops and heavily leafed treesFall: distinct field patterns because of the various stages of crop development and harvestingWinter: when there is little or no snow cover, tones are generally drab and dull

Tone

See Notes for Interpretation http://www.sd36.bc.ca/sites/semiah/

mleziva/unit2/U02L09.htm

Homework