geography f764 - skills

SAMPLING FRAME 

SPATIAL - where that location will be (river study)

NON SPATIAL - who to ask (questionnaire)

METHODS 

• Random 

• Stratified 

• Systematic 

• Pragmatic 

DESCRIPTION 

• random number tables to select sample point with every idividual variable having equal chance of being picked 

ADVANTAGES 

• stat. tests 
• no bias 

DISADVANTAGES 

• may not be representative of total statistical population (miss points)
• takes a long time 

DESCRIPTION 

• underlying subdivisions in total stat. population are taken into account 
• propotinally sampled 

ADVANTAGES 

• no points missed or overepresented 

DISADVANTAGES 

• possible bias - invalidate inferences made from statistical tests 
• possibly no stat test 
• need to get info of underlying patterns
• groups under / over represented in proportional sampling  

DESCRIPTION 

• points are selected at regular intervals 
• spatial (where) + non-spatial (who)

ADVANTAGES 

• easy and quick 
• allows even coverage to test hypothesis 

DISADVANTAGES 

• bias 
• interval may coincide with data / location 
• possibly no stat 
• missed vatiations + regularities not typical 

DESCRIPTION 

• where you can get access to 
• and where changes can be observed 

ADVANTAGES 

• realistic 
• risk assessment based

DISADVANTAGES 

• bias 
• possibly no stat test 

Point

• number of individual points  

Grid 

• Quadrat used at indivial points 

Line 

• transect - measurements along a line 

Belt transect 

• wider transect 

DESCRIPTION 

• level at which data is exact and free from error 

ERRORS

measurement error -

• repeating increases room for error 

operator error -

• idividual / equipment / climatic 

DESCRIPTION

• extent to which sample data reflect the greater whole statistical population 

ERRORS

sampling- 

• inappropriate sampling frame 
• small sample size 

IDENTIFY RISK 

EVALUATE SEVERITY (1-5)

CONTROL MEASURES

RE-EVALUATE SEVERITY (is it acceptable with control?)

DESCRIPTION 

• a small scale preliminary study used to evaluate successes / weaknesses and improvements to study design prior to performance of a full scale research project 

ADVANTAGES 

• identify improvements 
• if given time is acheivable 
• if location is appropriate 
• effectivenesss of sample method - representative, accurate, reliable 
• risk assessment 
• equipment effectiveness

DISADVANTAGES 

• takes time 

TRENDS to be represented 

SPATIAL - patterns between areas 

TEMPORAL - patterns overtime 

TECHNIQUES 

• maps (QUAL/QUANT)

• graphs (QUANT)

• diagrams (QUAL/QUANT)

• annotated field sketches / photos (QUAL)

1. Chloropleth 

2. Dot 

3. Proportional Symbols 

4. Isoline / Isopleth 

5. Flow line 

DESCRIPTION 

• ratio values expressed as densities or percentages 
• use of area 

METHOD 

• standardized values (%)
• divide into classes 
• class sizes (fixed / mathematical calc / dispersion in data)
• colour shading system 
• title, key, scale, direction

ADVANTAGES 

• easy + useful for area census data / good visual patterns 

DISADVANTAGES 

• conceal variations in areas / abrupt changes at bounday / large units dominate / broad boundaries 

DESCRIPTION 

• ratio data 
• areas

METHODS 

• find base map with boundaries 
• decide on dot value (represent low values) + size (just touch in high density areas)
• place on maps 
• key, title, scale, direction 

ADVANTAGES 

• only one which provides info within wards 
• visual + spatial patterns + not interupption at area boundaries 
• statistical ananlysis 

DISADVANTAGES

• high densities dots merge 

DESCRIPTION 

• ratio data in specific location / or absolute 

METHODS 

• suitable scale base map 
• choose symbol + scale 
• calculate size / area of symbol 
• plot in central of area 
• add key, title, scale and direction 

ADVANTAGES 

• good visual + spatial 
• data can be recovered and can show whole range of values 

DISADVANTAGES 

• hard scale to decide upon / larger symbols misread / difficult to place on small maps 

DESCRIPTION 

• ratio data
• uses points 

METHOD 

• suitable scale base map 
• decide on number and value of isolines 
• draw by interpolation 
• number isolines 
• add key, title, scale, direction 

ADVANTAGES 

• clear spatial patterns / shows gradual changes / guess of values between data 

DISADVANTAGES 

• need a lot of points / assuming constant change / only used if variable changes with space

DESCRIPTION 

• ratio data 
• uses lines to show flow paths (routed/ actual pathways or non-routed/ straightlines) 

METHOD 

• suitable scale where flow lines can be recorded 
• number of classes + scale of line (width)
• key, title, scale, direction 

ADVANTAGES 

• visually shows patterns of movements + quick/easy 
• can show different variables of direction 

DISADVANTAGES 

• very generalised + hard to stat. test 
• carefully chose width scale 

Tables 

Charts 

• Bar Charts 
• Divided/Stacked Bar Charts 
• Pie Charts 
• Rose/Star Charts 

Graphs 

• Line Graphs 
• Scattergraph 
• Triangular Graphs 
• Lorenz Curves 
• Kite Diagrams 

DESCRIPTION 

• nominal data (presence or abscence) in form of parish names 
• interval/numerical data in form of % of arable 

• freq. distribution - values grouped into numerical values 
• used to construct histogram 

ADVANTAGES 

• backbone for then contructing futher presentation techniques 
• clearly group data into individual classes
• statistical tests 

DISADVANTAGES 

• no spatial pattern / visual represenatation 

DESCRIPTION 

• interval and discrete data used 
• quantities to be compared 
• width constant and legth varies 

ADVANTAGES 

• visual with temporal/spatial 
• stat. tested + comparable 

DISADVANTAGES 

• non-continuous data cant be used 

DESCRIPTION 

• quatity that can be divided into component parts 
• absolute values or porportions 

ADVANTAGES 

• easy to draw / interpret 
• visual pattern identified 
• stat. test 

DISADVANTAGES 

• too many divisions will confuse 

DESCRIPTION 

• uses % data 
• circular chart divided into segments of a whole sample

ADVANTAGES

• visual and easily comparable 
• precise % allowing stat. tests

DISADVANTAGES 

• not always exact % 
• too many divisions confuse + no temporal change can be shown
• when comparing, order of division has to be standardised 

DESCRIPTION 

• used to show direction 
• length/width of bars show frequency 

ADVANTAGES 

• clearly show direction and spatial changes 
• visual pattern represented 
• can recover stat. if accurrate + to scale 

DISADVANTAGES 

• width/length scale hard to produce 
• may not be able to state exact direction 

DESCRIPTION 

• variations in absolute or % 
• X axis independent and Y dependent 
• X influences Y 

ADVANTAGES 

• trends, patterns and anomalies highlighted 

DISADVANTAGES 

• only continuous 

DESCRIPTION 

• show an overall trend, not just a line of points 
• simplest way of looking at relationship betweek 2 variables 
• first stage in stat analysis 
• closer points in straight line = stronger relationship 

ADVANTAGES 

• correlation suggested (line of best fit) 
• spearman's rank 
• spread of values 
• anomalies 

DISADVANTAGES 

• few points can skew data 
• too many confuse 
• only between 2 variables 

DESCRIPTION 

• visually represents 3 variables 
• must add up to 100% on each side of equilateral triangle 
• spatial and temporal

ADVANTAGES 

• 3 variables can be visually compared 

DISADVANTAGES 

• only % 
• can be difficult to read 
• can be difficult to construct 

DESCRIPTION 

• line graphs that show inequalities in distribution of a phenomena 
• cumulative frequency curves 
• striaght line shows even distribution 
• Lorenz curve shows actual distribution and how much it deviated from even 
• more concave = greater inequality 
• 'gini' coeffiecient calculated to show degree of inequality 

ADVANTAGES

• viual patterns identified 
• plot more than 1 distribution 
• gini coefficient calculated 

DISADVANTAGES 

• time conuming to calculate cumulative freq. 
• no exact quantative measure of degree of inequality 

DESCRIPTION 

• shows how a phenomena's occurence changes over distance 
• e.g bradshaw's model 

ADVANTAGES 

• visually effective 
• recove stat. tests 
• relative phenomena compared 

DISADVANTAGES 

• only show % change, not absolute values (Bradshaw - no values) 

DESCRIPTION 

• box to keep in area sketching 
• add only essential infromation (locational reference points)
• add an approximate scale 
• add title and orientation 

ADVANTAGES 

• simple and easy to interpret 

DISADVANTAGES 

• to be effective needs scale, key, labels, direction 

MAPS 

• plan view indicating scale + direction 
• shows what exists in area (characteristics / economic activity ...)
• flexible scales 
• GIS - shows layering 
• sometimes dated - doesnt show present 
• shows scales + spatial data 

PHOTOS 

• aerial, oblique, ground level, satellite views 
• capture at instant in time 
• shows what is there at that time 
• shows variety of data - colours, veg... 

AEGIS 3 software used in connect with pilot study 

• data stored, organised, combined with other data and then displayed 

ADVANTAGES 

• cope with large amount of data 
• cope with large variety 
• easily change scale 
• dynamic - cope with change 
• allows spatial data to be investigated to show patterns / trends 
• information tied to places 

USES 

1. collecting / recording data - (primary / weather  + secondary / census data) 

2. presenting data - (area / line / point / symbols / colours / overlayed / compared) 

3. analysing / interpreting - (investigate + answer questions)

PRIMARY 

• unprocessed 
• not analysed or interpreted 
• geogrpaher has direct control 

SECONDARY 

• dervived from published documents that has been anlysed/ interpreted 
• includes processed census data, research papers, published maps, textbooks

QUALITY 

Nominal - lowest quality (0 or 1) / only stat tests are Mode + Chi Squared 

Ordinal - rank ordering / only stat tests are Spearman's rank, median, percentiles 

Interval - discrete scale + allows magnitude / stat tests include mean, SD, Spearmans, regression

Mean - includes anomalous data 

Median 

Mode 

Standard deviation - measures central tendancy around mean 

Kurtosis - the taller/steeper the curve the lower the standard deviation 

Distribution - normal (bell shaped curve) +Ve skew (mean greater than mode) -Ve skew (mode greater than mean)

Spearman's Rank Correlation Coefficient 

DESCRIPTION 

• doesnt have to be normally distributed data 

POSITIVES 

• easy and simple 
• doesnt have to be normally distributed (test other variables)

NEGATIVES

• a poor statistical test 
• no magnitude 
• no explanation for causes of strength of relationship 

DESCRIPTION 

• degree of freedom (N-2)
• standard significance level 0.05 (95%)

ADVANTAGES

• can say whether results are respresentative of total stat. population 
• whether they are significant 
• reduces problem of BIAS / due to CHANCE 
• whether we can be 95% sure of this 

NULL H1

• relationship found in sample is not representative of total stat. population 
• testing for no relationship

ALTERNATIVE 

• relationship in sample does accurately reflect total statistical population 

Pearson's product moment correlation coefficient 

DESCRIPTION 

• have to have each individual point normally distributed 

ADVANTAGES

• statistically better
• more specific 
• gives magnitude 

DISADVANTAGES

• can only use normally distributed interval data 
• harder to construct 
• doesnt give reason for relationship 

DESCRIPTION (e.g. corrie orientation)

• observe differences between comparable sets of data (manufacture set from averages)
• null hypothesis put forward - random distibution 
• data collected so can be grouped into classes
• compare to significance test to confirm whether any deviation from random in observed data is by chance 
• if > critical value then we can reject the null hypothesis 

DESCRIPTION 

• allows us to statistically describe the distribution of settlements 
• use 'central place theory' to test this 
• whether they are clustered / random / regular 

0 = CLUSTERED (H1)

1 = RANDOM (H0)

2.15 = REGULAR (H1)

• can be due to many different factors 
• e.g settlement distributions 
• whether you measure as crow flies or along roads 
• SERVICES affect location