How do we indicate direction? Applying map skills and techniques
• Direction - general direction from one feature to another, also known as 'wind directions'. What is scale?
• Compass points - divided into cardinal points and major intermediate points. • Maps produced at various scales.
• Minor intermediate points include north north east (NNE), east north east (ENE), east south • Relationship between map and ground shown differently.
east (ESE), south south east (SSE), south south west (SSW), west south west (WSW), west • Word scale: Map distance and ground distance written in
north west (WNW), and north north west (NNW). abbreviated units.
• Bearing is a more accurate way of indicating direction, measured clockwise from north at o° • Representative fraction: Numerator represents map distance,
through a full circle to 360. denominator represents equivalent ground distance.
• Ratio scale: Map distance relative to equivalent ground
distance.
What is true north? • Line scale: Ratio between map and equivalent ground
distance on scale bar.
• Comprises with north pole on Earth's U1: Mapwork • Map scale allows conversion to ground distances.
surface. techniques (A) • Scales compared for small and large scale maps.
• Meets all meridians or lines of longitude.
How do you calculate distance and area?
What is magnetic north? • Differentiate between straight and curved line distances.
• Use topographic maps and orthophoto maps for distance calculation.
• Earth acts like a magnet with spherical magnetic field.
• Convert map distances to ground distances before calculation.
• Magnetic poles move near true poles due to magnetic forces.
• Convert km2 and m2 area to hectares (ha).
• Magnetic north, located in northern Canada, points to compass.
• Convert km2 to hectares by multiplying by 100 and m2 to hectares by dividing
• Magnetic north shifts east or west of true north.
by 10,000.
What is magnetic declination What is the relationship between
and how is it calculated? contours and cross-sections?
• Defines angle between true north and magnetic north. • Contours are lines connecting equal height places above sea level.
• Variates from place to place and year to year.
• Drawn at regular intervals.
• Maps display magnetic declination and annual change.
• Vertical distance between consecutive contours equals the contour interval.
• Magnetic bearing = true bearing + magnetic
• Spacing between contour lines determined by ground's vertical steepness. Indicates slope - landform.
declination.
• Best viewed in freehand cross-section for general land shape impression.
• True bearing = magnetic bearing - magnetic declination
• Features include far apart, closely spaced, evenly spaced, grouped, convex, and consecutive contours.
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, What is grid referencing?
• Geographic Coordinate System Overview:
• Determines exact location of Earth's features.
• Includes latitude north or south of the equator and longitude east
or west of Greenwich meridian.
• South Africa's location is indicated as south and east, with each
degree subdivided into 6 min and 6 seconds.
• Subdivisions include degrees into 60 min and minutes into 60 sec.
Map and photo interpretation
• Based on physical feature analysis/mapwork techniques.
• Supported by climate, geomorphology, settlements,
economics knowledge.
• Requires observation of interrelationships.
U1: Mapwork
techniques (B)
What do you already know about maps?
• Visual representations of natural and constructed features.
• Scale models of reality.
• Depict geographic objects - roads, towns, railway lines, rivers.
• Show points, lines, surfaces, and space.
• Use different colours for specific object types.
• Display quantities like built area densities, contour values,
How do you use maps and other and intervals.
graphical representations?
How do you read and analyse
• Synoptic Weather Maps:
• Communicate themes through symbols. physical and constructed features?
• Display pressure systems, fronts, lows, ridges, pressure • Map and Photo Interpretation Skills:
gradients, air movement, cyclones, and weather conditions. • Not taught through books.
• Enhance with wind, rainfall, temperature graphs. • Mastery through frequent exercise.
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, What is intervisibility? What is gradient? The South African 1:50 000
• The ability to see features from specific points. • Defines slope's steepness (gentle, moderate, topographic maps
• Crucial to identify which places can be seen from steep, very steep).
another. • Measures slope. • Classification of Maps:
• Determining intervisibility involves examining • Based on projections, purpose, scale, and
contours. information content.
How do you calculate • Topographic maps: detailed, accurate,
• Intervisible points are those with no higher terrain
simplified Earth's surface features.
between them. gradient? • Features include relief, drainage, vegetation,
• Convex slopes indicate summit visibility from foot.
and constructed areas.
• Concave slopes indicate summit and foot intervisibility. • Expresses relationship between vertical and • Map references list features and
horizontal distance.
corresponding signs.
What is vertical exaggeration? • Uses RISE:RUN ratio. • Display geographic zone and coordinate grid.
• Measures units of measurement in meters. • Two-dimensional representations of the
• Cross-section Construction from 1:50,000 • Calculates gradient between top & foot of slope. environment.
Topographic Map: • Horizontal distance between spot heights is 2.1
• Maintains horizontal scale. cm on a 1:2 000 map.
• Exaggerates vertical – clearer height variations. What are the conventional
• Calculates dividing vertical/horizontal scales. map signs and symbols?
• Expresses both scales as representative fractions.
U2: Topographic • Topographic Map Interpretation:
maps • Defines surface features using symbols or
How do you construct cross- signs.
sections from 1:50 000 maps? • Maps convey message through symbols, seen
as language.
• Recommended to view landforms from What are landforms and how are they • Understanding symbols - crucial for
the side. interpretation.
recognised on a topographic map?
• Hills visible against sky in fields.
• Cross-sections or profiles drawn using • Earth's Surface Physical Features – range from large-
contour lines and height clues. scale to minor features. What are contours and landforms?
• Note heights, slopes, water courses, and • Shaped by weathering, erosion, deposition, and plate
• Maps: Two-Dimensional Representations.
features before profiled line drawing. tectonics.
• Show third dimension: height.
• Write contour values on paper above • Contour lines identify landforms. • Methods: spot heights, bench marks,
profiled line. • Essential for topographic map interpretation. trigonometric stations, contours.
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, U4: Examining a selection of satellite images
U3: Interpreting vertical
• Differentiated by spatial and spectral resolution.
aerial photographs
• Captured Earth portion size and revisit frequency.
• Meteosat: Low resolution 1km pixel image used for weather forecasting. Includes 12 bands and 30-minute revisit • Vertical Aerial Photography Overview
interval.
• Recording specific areas at specific
• Landsat: 15m pixel image used for land cover classification and change. 7 bands, 16-day revisit interval. Single times.
image size: 185 km x 170 km.
• Showing objects as they appear in
• Wordview 2: High-resolution image used for security, defence, urban planning, and disaster damage monitoring. reality.
• Easier to read than maps.
• Enables observation of object changes
over time.
U3: Aerial photographs • Interpretation from general patterns to
detail.
and orthophoto maps • Uses known to identify unknown.
• Uses 5 recognition elements: shape,
U4: Geographical pattern, size, texture, shadow, and tone.
Information Systems (GIS)
(A) What are orthophoto
maps and their
identifying features?
Comparing an orthophoto map • Vertical aerial photographs referenced
with a topographic map to precise x:y coordinates.
• True to scale - accurate distance, area,
• Topographic maps and orthophotos have unique characteristics. and angle measurements.
• Use together for landform identification. • Includes scale, place names, contour
• Orthophoto vs Topographic Map Comparison: lines, spot heights, trigonometric
• Orient orthophoto map on topographic map. stations, latitude, and longitude.
• Identify common features: natural, infrastructure, buildings, land use. • All orthophoto maps - 1:100 000 scale.
• Identify corresponding features on both maps. • Uses recognition elements for feature
identification.
• Identify newly built features or landscape changes.
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, Vector and raster data U4: Looking at GIS concepts
• GIS Data Storage Overview: Stores geographic dimensions of Earth's features. What is remote sensing?
• Stores attributes or characteristics of these features.
• Utilizes vector data and raster data structures. • High-resolution image used for security, defence,
• Vector Data: Represents point features by nodes. urban planning, and disaster monitoring.
• Linear features are represented by straight lines. • Spectral resolution of 8 bands.
• End points form an area (polygon). • 1.1-day revisit interval.
• Features' attributes are stored in a database. • Single image size of 16.4 km.
• Raster Data: Area is subdivided into grid cells, each with a numeric value representing a specific feature. • Collects Earth's land and sea surfaces
information.
• Allows geographers to research areas without
physical contact.
• Classified into active and passive systems.
U4: Geographical What is resolution?
Information Systems • Remote Sensing Sensor Resolution
(GIS) (B) Overview:
• Creates sharp, clear images.
• Types: spectral and spatial resolution.
• Spectral Resolution: Detects
information over various spectral
bands.
• GIS Technology Overview: Spatial and attribute data • Spatial Resolution: Defines the quantity
• Data: Clusters of organized facts and information. of detail detected in an image.
• Interpretation: Human or computer interpretation required. • Resolution in Earth's Surface: Low-
• Types of Data: Spatial data and attribute data. resolution depicts larger portions but
• Spatial data: Shape and position of geographical features. fewer features. High and very high-
• Attribute data: Information about spatial characteristics of features. resolution depict smaller portions but
• Characteristics can be qualitative or quantitative. more features.
• Examples: Non-spatial data like photographs.
• GIS Programmes: Utilize spatial data, positional data, scannable maps, and digital aerial and satellite images.
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, What is data manipulation? Data integration Data standardisation, data
• GIS Data Manipulation Procedures: • "Combining Multiple Data Layers for sharing and data security
• Changing map projections. Comprehensive Answers":
• Converting data from raster and vector formats. • Combines spatial and attribute data from all Data standardisation
• Interpolating between points. input layers.
• GIS technology is now integral to business
• Integrating data layers. • Facilitates complex spatial questions. and organizational information
• Creating buffers. • Combines different data layers for realistic, infrastructure.
• Creating models. complete answers. • Integration capabilities enable sharing of
• Conducting statistical analyses. different data sets for broader scenarios.
• Integration reveals relationships, patterns,
and links not visible in one dataset.
• GIS must produce useful information
Buffering products and provide consistent data
U4: Geographical integrity infrastructure.
• Identifies zones at different distances from
geographical features. Information Systems • Open GIS system facilitates geographic data
sharing, integration among GIS
• Example: Planting trees closer than 5m from drainage (GIS) (C) technologies, and non-GIS applications.
channels.
• Solution: Move factory location to avoid overlap with
residential area. Data sharing
• Early GIS focused on individual projects and data sharing.
Querying • Today's GIS integrates and shares spatial and non-spatial
Statistical analysis data for better decision-making.
• GIS for Geographic Information • Most GIS products read directly and transformed with
System:
• GIS Data Analysis Overview: minimal time delay due to open interoperability and new
• Allows querying for simple and
• Utilizes inherent position and technologies.
attribute information for feature
complex geographical questions.
creation.
• Displays solutions graphically. Data security
• Aids in data investigation and
• Example: Identifying shrubs on sandy additional information • Sensitive data for commercial, personal, or national security.
soils. identification. • Access restricted to authorized organizations/persons.
• Compares vegetation data layer with • Includes climatic data averages,
soils data layer. • Data security involves authorization codes.
spatial tendencies, and patterns. • Unrestricted portions of same data set accessible to general users.
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, U5: What are thematic maps? U4: Application of GIS techniques
• Atlas Overview: Who uses GIS?
• Book-format collection of maps.
• Facilitates data query, analysis, mapping,
• Shows spatial information at various scales. modelling, visualization, and display.
• Shows spatial distribution of specific • Serves diverse users - spatial information and
geographical themes. products.
• Includes non-spatial information like • Applicable in various disciplines.
diagrams, graphs, tables.
• Use examples include agriculture, forestry,
police, medicine, archaeology, defence, town
How do we examine thematic maps? planning.
• Thematic Maps Overview:
• Qualitative or quantitative. Who uses GIS?
• Map key includes common symbols. U4: Geographical • Land Information System (LIS): Used for
• Unique colours assigned to features. identifying geographical issues.
• Distinctive colours - value categories/class intervals. Information Systems • Facilities Management System (FMS):
(GIS) (D) Used for managing facilities.
Why do we compare information from • Environmental Information System (EIS):
U5: Using atlases Used for identifying environmental
different maps? conditions.
• Thematic Maps in Geography: • Farming Information System (FIS): Used
for identifying agricultural practices.
• Illustrate mineral distribution, resource use, and
industrial development.
• Recognizing Urban Heat Islands: Utilizes
Developing a paper GIS infrared band for night-time observation
• Provide answers to Geography's Four Big Ideas.
and temperature difference recognition.
• Multiple maps often needed for specific • Displays spatial data through layers representing single
themes/features. • Flood Detection and Monitoring: Utilizes
questions.
satellite imagery for rapid rainfall
• Uneven population distribution attributed to • Linking each spatial object with individual attributes.
estimation and flood extent
climate, resource availability, economic processes, • Allows data manipulation, integration/querying. determination.
water availability, and government policies. • Teaching GIS on paper for non-computer activities. • Spatial Data Management: Provides
• Investigate urban/rural population, climate, • Uses topographic maps with colour groups efficient tools for spatial analysis and
rivers/dams, agriculture, minerals, infrastructure, representing main features. visualization.
and political information.
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