GEOM90007 Chap.10 Tableau Mapping, Filters and Calculations
Tableau Mapping, Filters and Calculations
Define Tableau data model
Tableau Mapping, Filters and Calculations connects Tableau data model, filter context and calculated field along an information-visualisation pipeline: data type, visual encoding, perception, task fit and evaluation.
The practical aim is to build a map or dashboard whose data grain, filters and calculation order match the question; the display is defensible only when each encoding choice can be traced back to the analytical question and the structure of the data.
Place Tableau data model at its correct stage: question, data specification, transformation, encoding, perception, tool or evaluation.
For Tableau data model, record the variables, measurement levels, granularity, missingness and comparison task wherever they apply before choosing or judging a chart.
Use filter context to make the next transformation, encoding, layout, interaction or evaluation step explicit.
When filter context involves marks and channels, state which values they represent and check whether scale, ordering, aggregation or filtering changes the apparent pattern.
Use calculated field to test perceptual and task fit.
In Tableau Mapping, Filters and Calculations, ask whether viewers can make the required comparison accurately, whether uncertainty and exceptions remain visible, and whether colour, position, motion or interaction creates an avoidable accessibility or interpretation cost.
Tableau mapping
In GEOM90007, Tableau mapping belongs with Tableau data model and filter context because students use it to build a map or dashboard whose data grain, filters and calculation order match the question.
A defensible use of Tableau mapping should define the term, connect it to the case evidence and test the conclusion through calculated field; repeating the phrase without that chain does not demonstrate understanding.
Trace filter context
For the application — build a map or dashboard whose data grain, filters and calculation order match the question — compare at least one alternative encoding against the same data and task.
Retain the design only if the calculated field evaluation shows that it reveals the intended relationship without introducing a stronger distortion or hiding the evidence needed to challenge it.
Make a compact pipeline audit for Tableau data model: question or data field; transformation; mark and visual channel where applicable; intended task; evaluation evidence; and likely failure.
Locate filter context and calculated field at their actual stages so a technically valid implementation is not mistaken for an effective display.
Test a changed filter context view. Hold the data and question stable, replace the channel most closely tied to filter context, and predict which comparison becomes easier or harder.
Evaluate the result with calculated field, including uncertainty, accessibility and the possibility that an apparent pattern is produced by scale, binning, projection or interaction state.
Critique Tableau Mapping, Filters and Calculations in task order: state the question around Tableau data model, classify the data, describe the role of filter context, predict the perceptual judgement and report the calculated field evaluation evidence.
Revise the first stage where calculated field shows that the visual no longer supports the task instead of adding decoration to a structurally unsuitable chart.
Test with calculated field
A complete response should make the task visible before the detail: identify what must be decided, define the relevant terms, connect the evidence to filter context, and use calculated field to test the result.
The final sentence about calculated field should answer the question actually asked rather than merely repeat the topic.
The controlling limit is specific: A visually correct view can still aggregate at the wrong grain or change meaning under an unnoticed filter.
Keep that calculated field limit beside the worked example, because it separates a careful GEOM90007 answer from one that sounds confident but claims more than the task or evidence supports.
For revision, retrieve Tableau data model, filter context and calculated field without notes, explain their relationship aloud, then complete a changed version of the application: build a map or dashboard whose data grain, filters and calculation order match the question.
Record the first failed filter context reasoning move and repair it before attempting another case.
What this chapter covers
- 01
Tableau data model
- 02
filter context
- 03
calculated field
- 04
Applying Tableau data model
- 05
Limits of filter context and calculated field
Worked example: Tableau Mapping, Filters and Calculations
- 1Mark the starting condition or object represented by Tableau data model.
- 1Write the change, rule or mechanism supplied by filter context as a verb-led link.
- 1Show how that link reaches calculated field; do not skip an intermediate actor, quantity or stage.
- 1Answer the task with the completed chain and preserve this limit: A visually correct view can still aggregate at the wrong grain or change meaning under an unnoticed filter.
Key terms
- Tableau data model
- The relationships and logical tables through which Tableau combines data while preserving an intended level of detail. Use this definition when the task is to build a map or dashboard whose data grain, filters and calculation order match the question.
- filter context
- The set and order of filters that determine which records are available to a Tableau calculation or view. Use this definition when the task is to build a map or dashboard whose data grain, filters and calculation order match the question.
- calculated field
- A reusable expression that derives a new value from existing fields within Tableau's evaluation rules. Use this definition when the task is to build a map or dashboard whose data grain, filters and calculation order match the question.
Tableau Mapping, Filters and Calculations FAQ
What is the main task in Tableau Mapping, Filters and Calculations?
Build a map or dashboard whose data grain, filters and calculation order match the question.
How do Tableau data model and filter context work together?
Use Tableau data model to establish the object or condition, then use filter context to explain how it changes the outcome being analysed.
What must a GEOM90007 answer qualify here?
A visually correct view can still aggregate at the wrong grain or change meaning under an unnoticed filter.
How should I revise Tableau Mapping, Filters and Calculations?
Retrieve Tableau data model, filter context and calculated field, apply them to a changed case, and correct the first point where the evidence no longer supports the conclusion.
Assessment move
Reconstruct the relationship among Tableau data model, filter context and calculated field; complete the chapter application without notes; then test the result against this limit: A visually correct view can still aggregate at the wrong grain or change meaning under an unnoticed filter.
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