SIP Operations

Example from Basic Ops. II: Layer Superimposition (Cover)

A Brief Introduction to GIS

Reading Corner

For next week: Chapter 1: “What is a GIS”

Announcements

Call for Lab Supervisors

• meeting on Thursday Jan 20 2:15-2:50 PM in the GIS Lab

Call for Ombudsman/Ombudswomen

• we will meet in week 5 (early Feb) and week 11

Honorary Mentions

Changes to the course this year

• how many?
• the 1st one being....

During the break —

• I’ll collect GIS 2000 $ 20.- deposits w/note with name/tel/e-mail

Lab Announcements

• Iomega Tools Utility
• Kevin and Robin’s policy on Assignments
• Colleen’s MF Works Tuturial file

Questions?

In Today’s Lecture:

• SIP Data (end from last week)
• SIP Operations
• Example from Basic Ops. II: Layer Superimposition (Cover)
• A Brief Intro to GIS
• Recode and Slice ?

SIP Data (continued from last week)

SIP Operations

• Spatial image processing operations use one, two, or more input layers to do their work, resulting in a new output layer.
• The imaginary 2.5D solid is dynamic in the sense that it grows by accretion of derivative layers.

* Diagram *

Image Processing of Stacked Layers

• Spatial image processing can be viewed as the process of applying a function to one or more stacked input layers(s). The result is a transformed output layer.
• Using symbolic notation we can describe this process as:
• I(x,y,z)(1...n) —f(x,y,z)—> O(x,y,z)
• (P.S.: there’s some, but not much, math in this course)
• Functions are implemented in software as Operations and Procedures.
• A function can be an ‘atomic’ operation, or:
• A function can be a high-level procedure made up of a set of operations (user-composed “macros”).

* Diagram *

A Diagram and Table show our SIP taxonomy

* The Applied Taxonomy Diagram *

* The Applied Taxonomy Table *

The taxonomy consists of four groups, with four operations per group.

Similar to Downhill Skiing, the groups are ordered in the taxonomy by ascending level of user-skill:

Basic I —> Basic II —> Intermediate —> Advanced

This taxonomy is primarily based on an order of teaching/learning—

geared to varying levels of user skill from basic, through intermediate, to advanced.

Overall, sixteen (16) common types of spatial image processing operations are included in the taxonomy

The criteria for placing an operation in a specific group:

Primary: Simplicity and Usefulness, and

Secondary and partial: Type-of-Function

Summary and Conclusion

The goal of the AppliedGrouping is to facilitate the process of mastering spatial image processing.

Mastering involves not only learning the operations, but also developing the ability to combine them in models and procedures.

Mastering use does not have to be so befuddling.

Modern graphic user interfaces (GUIs) illustrate that there is a choice.

We also know that designs aimed at making information accessible can be greater or lesser puzzles.

A parting Hypothesis: By having an explicit applied/user orientation

the taxonomy not only facilitates learning, but

also itself becomes a problem solving and modeling tool.

And a parting note: Scripting is a bit like playing the piano

(or computer programming, problem solving, etc.)

beginners take a while to learn

while maestros are in demand

Example from Basic Ops. II: Layer Superimposition (Cover)

Layer Superimposition is a classic example of a GIS operation

since the layered approach is a fundamental construct in GIS

The Cover operation is often used for layer superimposition

although there are also other ways (operations) that can, and will be used

The Cover operation is used for both:

Transparent Overlay. Creating overlays by using partially transparent layers to augment features.

Mask Overlay. Creating a mask by using partially transparent layers to exclude features.

The common way of specifying a Cover operation:

FusedLayers = Cover map [With map ] ;

Explanation of the operation and its modifiers.

Note that [With map ] can be repeated several times.

An Example.

/* Cover Land Cover with the waterways, the buildings, and the roads */

ViewInContext = Cover «Land Cover» With RankedWaterSheds With Buildings With Transportation ;

The paired Recode and Cover (or vice versa) are a very common sequence in procedures.

A Brief Introduction to GIS

What essentially is GIS?

GIS can be represented by a Venn Diagram that has Automated Cartography, Spatial Analysis, and Geographic Database circles.

[•BlackBoard•]

A further reduction can be often achieved by simply invoking the 2 words Modern Cartography.

note: because cartography can be seen to subsume a degree of data base processing and spatial analsis.

And for the layperson — Modern Map Making and Use is not a bad way to characterize or look at GIS.

GIS paradigms are abundant:

• applied/user paradigm: possibly the broadest category. Think of a 3-D web of interdisciplinary applications, replete with sub-views of what GIS is. [• academic disciplines•]

note : the academic discplines transparency denotes “The Great Export of Geographic Method!”

• analytical cartography paradigm: computational, quantitative, scientific, knowledge representation issues...

• technological: GIS as ‘skill’, keywords: ‘GIS analyst’, college accreditation, ‘technicians’

• software development: computer science oriented (someone has to develop the thing)

What is the student and others’ excitement all about?

• from descriptive to derivative: the ability to progressively generate new information (Michael Gould, GIS World Sourcebook, 1996)

— and the ability to make implicit spatial relations explicit

e.g. multiple distances

from internal to external: from passive cognition to active manipulation—

to think spatially and to be able to actually do something about it

End of Lecture