Geoprocessing Geoprocessing is a fancy name for Spatial Operations So what is Geoprocessing? Processing or manipulating of geographic/spatial data to create a new dataset.

Example of a simple process Water Sugar Flour MIXED DOUGH

A typical Geoprocessing Input Dataset Output Dataset Geoprocessin g Unprojected Data Project Projected Data A process contains tool And a tool has parameters Input Data Output Data Tool

Geoprocessing/Model building Process

Tools in ArcToolbox There are literally hundreds of Geoprocessing tools available in ArcGIS! Most of the time you will use only a few of them

Geoprocessing Menu Commonly used tools are available from Geoprocessing menu!

Environment Settings Application level settings affect all tools and menus Tool settings affect one execution of one tool

Workspace settings Current and scratch workspace Output coordinate systems

ArcToolbox has many tools

Map Overlay Map overlay brings data from multiple layers into one There are two basic categories of map overlay functions 1. Functions that combine attribute data & 2. Functions that do not

Overlay operations in ArcGIS 1. Erase 2. Clip 3. Union 4. Intersect Overlay operations combine more than one layers into one. Some of the extraction function can also be considered as overlay function Extraction only & does not combine attribute from layers Combine attributes from layers

Select by location Can’t truncate the roads at the boundary!

Clip is the rescue! Clip is used to cookie cut the original ROAD layer into a smaller layer

What is Clip? Clip is used to cookie cut the desired areas

Erase Only the features outside the Erase feature are kept, everything else are erased

Dissolve Dissolve is used to aggregate features based on specified attributes If you don’t choose an attribute, it will dissolve all into one!

How to simplify the landuse data DISSOLVE

Dissolve wizard

What is Union? Union combines two polygon layers together

What is Intersect? Computes geometric intersection of two layers

Example of intersect Areas common between the two layers. INTERSECT 3500’ buffer 2000’ road buffer

Buffering Lines 250’ Buffer

Using attribute table in buffering

Variable buffering using attribute

Multiple Ring Buffer

Buffer around Toxic Sites & water well location