Analysis in 9.0

What’s Next

• To be really accomplished in GIS (or GIT) you need the following …– Vector GIS (You got it)– Raster GIS (FOR556)– Expert in Vector GIS (FOR558)– GPS FEG XXX– Remote Sensing FEG XXXXXXX– Database management (FEG xxxx)

For Science & Engineering

• Biology – Raster and Vector …For556 and Myra Hall’s xxxx (final project can be same for both)

• Landscape Architecture – Vector GIS (FOR558) and AutoCad

• Forestry – Vector GIS (FOR558 & 556)

• Engineering (see previous slide)

For556, Spatial Modeling• Use IDRISI to solve problems dependent on

continuous surfaces ( elevation, water table, viewsheds, etc.)

• Emphasis is NOT on learning the software – that is easy

• Emphasis is on Creative Thinking through applying the technology to problem solving

• Like 557 has weekly exercises that provide less cookbook instructions as the semester progresses

• Quizzes but no exams; final problem

FOR558 Advanced Topics• Next semester will be ArcGIS

• Emphasis on– Editing vector data – a tricky business

in ArcGIS– Analysis– Using Data Models like

• ArcHydro for hydrologic modeling• Forestry Data Model for forest

management• Planning Data Model

– Grid processing and modeling

The latest and greatest

development in GIS

FOR558 Advanced Topics• Next semester will be ArcGIS

• Emphasis on– Editing vector data – a tricky business

in ArcGIS– Analysis– Using Data Models like

• ArcHydro for hydrologic modeling• Forestry Data Model for forest

management• Planning Data Model

– Grid processing and modeling

Small class – exact topics covered depends of interests of enrollees

Sales Pitch Over

On to

Analysis

In 9

Analysis

• Possibilities are the same as AV3.3– Select by Attribute (Query Builder)– Select by Location (Select by Theme)– Overlay Analysis (GeoProcessing Tools)– XTOOLS (XTOOLS)

(but not the same xtools!)

Selection

IMPORTANT!

Selection Options• Lots of

control of how features are selected

Select by Location

Same stuff as AV3 but use is a little different

Select by location Options

Select Features from

Add to the currently selected features in

Remove from the currently selected features in

Select from the currently selected features in

Select by location Options

Lots of choices here -- and they all do slightly different things

Pick your layers here

Here are some actions…

• Watch the bottom of the dialog and make sure it is doing what you want it to

• That sounds easy but quite often NOT easy

• Here are some of the options

Options:Intersect

Options: Intersect

Options:Touch Bndy of…

Options: Have their Center in…

Options: Are completely w/in…

Options: w/in a distance of…

Options: are contained by…

Overlay Operations

• Overlay operations are like the “select by location” functions but not the same.

• Both use two layers– Select by location just selects

features– Overlay operations create new

feature classes

Toolbox

Overlay: Erase• From Help: Erase feature removes a chunk of

the input feature• It is important to keep Input and Erase feature

correct or GIGO

Overlay: Identity• Computes a geometric intersection

(logic) of the input and identity features• Input features (or portions thereof) that

overlap the identity features will get attribute features from the identity features

• To put it another way: combines the portions of features that overlap the identity features to create a new feature class.

Overlay: Identity• Computes a geometric intersection

(logic) of the input and identity features• Input features (or portions thereof) that

overlap the identity features will get attribute features from the identity features

• To put it another way: combines the portions of features that overlap the identity features to create a new feature class.

Clips by the Input feature and then UNIONS what is

left.

Overlay: Intersect• Computes the geometric

intersection of the input features or portions of features COMMON to all layers.

• This tool builds a new feature class from the intersecting features common in both feature classes. Available with any ArcGIS license.

Overlay: Intersect• Computes the geometric

intersection of the input features or portions of features COMMON to all layers.

• This tool builds a new feature class from the intersecting features common in both feature classes. Available with any ArcGIS license.

Intersect is NOTthe same as

Identity

Overlay: Symmetric Diff

• Computes a geometric intersection of the input and update features. Any features COMMON to ONLY one of the inputs will be written to the output

• Or to put it another way: This tool creates a feature class from those features or portions of features that are not common to any of the other inputs.

Overlay: Symmetric Diff

• Computes a geometric intersection of the input and update features. Any features COMMON to ONLY one of the inputs will be written to the output

• Or to put it another way: This tool creates a feature class from those features or portions of features that are not common to any of the other inputs.

This is the olive drab feature showing

through a hole in the yellow feature!

Overlay: Union

• This computes a geometric intersection of the input and output feature classes . ALL features will be written to the output feature class with the attributes from both.

• Or: This tool builds a new feature class by combining the features and attributes of each feature class.

Overlay: Union

• This computes a geometric intersection of the input and output feature classes . ALL features will be written to the output feature class with the attributes from both.

• Or: This tool builds a new feature class by combining the features and attributes of each feature class.

UNION: another view

Overlay: Update

• Computes the geometric intersection of the input and update features. The attributes and geometry of the input features are replaced by the update features.

• This tool updates the attributes and geometry of an input feature class or layer by the Update feature class or layer that they overlap

Overlay: Update

• Computes the geometric intersection of the input and update features. The attributes and geometry of the input features are replaced by the update features.

• This tool updates the attributes and geometry of an input feature class or layer by the Update feature class or layer that they overlap

Overlay: Summary

IDENTITY INTERSECT SYM-DIF UNION UPDATE

Summary

• The analysis tool in ArcGIS are very powerful

• And fairly easy to understand … one at a time!

• It is the combining of the overlay and selection tools to solve a problem that is the problem!

Sewbuf300

BufferSewersw/in 300m

Streamsnot w/in

20m

SewerOKERASE

Landuse:brush

lucode=300

SoilsSuit > 2

Strmbuf20

Buffer

OK sitesIDENTITY

Land OKIDENTITY

Of selectedpolys

Query

Query

Sel by Theme: Intersection

• Intersected Parcels w/ Cover with Ag Selected

• The red outlines are the selected parcels

Lets Zoom In ----

Select by theme

• You can see that• Entire Parcels

were selected• Parcels with only

a little bit of Ag landuse were selected

Overlay Intersection• BUT THE RESULT IS VERY DIFFERENT!

Red outlines are the parcels selected by Select by theme

Green are the result of the Overlay

So you have to be careful!

• Exercise 6 has you experiment with some simple layers

• And I will be throwing some relatively simple problems your way to provide more practice

• And I will be changing the schedule at bit too.