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: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 NOT the 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!
Sewbuf 300 Buffer Sewers w/in 300m Streams not w/in 20m Sewer OK ERASE Landuse: brush lucode=300 Soils Suit > 2 Strmbuf 20 Buffer OK sites IDENTITY Land OK IDENTITY Of selected polys 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.