What is attribute data?
descriptive and informs spatial data
Steps of attribute data managemnet?
What is validation?
What is manipulation?
Manipulation of Attributes: Creating Different graphs
▪ Single vs multiple variables;
▪ Individual vs classes of values
* Data dictates which graph is best
* Numerous possibilities:
1. Line
2. Bar
3. Cumulative distribution
4. Scatterplot
5. Bubble plot
Calculate geometry:
> Area
> Length
When do we use line graphs?
Display data as a line: Example, Shows data changes over time
When do we use bar charts?
Uses bars to show the number/frequency of values falling within each class
Cumulative distribution graph
pie chart
what are types of Attribute Data?
data can be classified according to its:
* Type
* Measurement scale
Data type refers to how a GIS stores attribute data
* Common types include:
Types of Attribute Data
* Number
* Text
* Character
* Date
* Binary large objects (BLOB) e.g.
images, audio or multimedia
Sorting attributes in GIS - software
types of attribute data: scale and precision table
Precision describes the number of digits that can be stored in the field, while scale describes the number of
decimal places. Negative numbers require additional precision to store the negative sign.
measurement scale of attribute data?
Categorical + Qualitative:
1. Nominal
▪ No ranking/Used for naming
2. Ordinal
▪ Ranking with no number (Large > Medium > Small)
Numeric + Quantitative:
3. Interval
▪ Have known numerical intervals but no absolute zero (Temperature
°F/°C)
4. Ratio
▪ Same as interval but has absolute Zero ((Temperature Kelvin)
Nomianl/ qualitative attribute data?
▪ Categories (“Names of items”)
▪ Subject/theme differences
▪ Grouped in categories based on qualitative data
▪ Not possible to measure the difference between two themes
▪ No rank
▪ For example:
▪ Road vs River
▪ Border or boundary
▪ Land vs. water
▪ Animal species
Ordinal/ qualitative attribute data?
▪ Ordinal measurements describe
order
▪ Ranked categories, no inference to
spaces between rankings
▪ Class differences & rank/position
within class
▪ Grouped in categories based on
quantitative data
▪ For example:
▪ 1st, 2nd , 3rd etc
▪ Degree of soil erosion, e.g. light,
moderate, severe
▪ High/medium/low
▪ Ratings (1, 2, 3 stars)
interval/quantitative attribute data?
▪ Ranked categories with known units
between rankings
▪ Operations of addition and subtraction
have meaning
▪ Based on quantitative data
▪ Zero does not mean no data
▪ For example:
▪ Temperature (Celcius )
▪ Ex. 40 degrees C is warmer than 30 or 20
and 0 means freezing point.
ratio/ quantitative attribute data?
▪ Ranked categories with known units between intervals
▪ Operations of multiplication and division can be employed
▪ Based on quantitative data
▪ But…based on an absolute zero.
▪ Numerical values with the zero feature denotes an absence of a
feature
▪ For example:
▪ Precipitation
▪ Population
▪ Temperature (Kelvin)