Introducing ArcGIS Chapter 1

Objectives  Understand the architecture of the ArcGIS program.  Become familiar with the types of data files used in ArcGIS.  Learn how to explore data files using ArcCatalog.

Storing Map Data  Vector vs. Raster  x, y coordinates (sometimes z)  Attribute Information represented (i.e., soil type)  Georeferenced Tied to a specific location on the Earth’s surface

Vector Model  Features X, Y coordinates  Points  Lines  Polygons

Vector Model  Point 1 x, y coordinate  Line 2 x, y coordinates  Nodes  Polygon More than 2 x, y coordinates Vertex (vertices)

Vector Model  Feature Classes 1 type of geometry Share a table containing their attributes Have like attributes

Vector Model  FID (feature identification code)  Thematic mapping Displaying features based on their value

Vector Model  Storing feature classes Shapefiles (shp)  One feature class Coverages

More storage… Feature Datasets  Roads  Traffic lights  Railroads  Gas stations

Fact of the day…. A regular hen's egg has about 7,000 tiny pores in its shell.

Two basic models…  Topological Stores spatial relationships between features in addition to their x, y coordinates.  Spaghetti Stores spatial features as a series of x, y coordinates Does not store topological relationships

Benefits of Vector  Stores with high degree of precision  Flexibility  Mapmaking  Compact storage  Certain types of analysis

Drawbacks of Vector  Does not store continuous information well Elevation, precipitation, etc.  Time consuming analysis for some types

Raster Model

 Grid-cell  Row and column  Land use  Resolution Higher=more precise Lower=less precise

Two types of Raster  Discrete Few values repeat themselves  Roads  Continuous Range smoothly from one location to another  Elevation

Benefits of Raster  Continuous data  Analysis are simple to perform  Map algebra Algebraic expression

Drawbacks to Raster  Precision vs. storage  Ability to store attributes To store geology and infiltration values, need two rasters

ArcGIS overview  ArcMap Display, analyze, edit spatial data  ArcCatalog Viewing and maintaining spatial data files ALWAYS use to delete, copy, rename, move files

ArcToolbox  Collection of tools and functions  More can be downloaded

Data Files  Shapefiles Only one feature class Points, lines, polygons Green icons Must contain: .shp The main file that stores the feature geometry .shx The file that stores the index of the feature geometry .dbf The database of attributes

Coverages  Oldest  Multiple feature sets.adf (arc data file)  Yellow icons

Geodatabases  Multiple feature classes  Include tables  Rules Stop light must be on road  2 types: Personal  Ind. & Microsoft Access Enterprise  Groups and editing

Database connections  Permits users to log in and utilize data from an enterprise geodatabase.

Layer Files  Does not contain spatial data  How it should be displayed  Store symbols

Rasters  Binary format

Tables  Unassociated with spatial data set  Standalone tables .dbf (dBase format)

Others  Grids Raster format  Internet Servers Image=print Feature=download  TINs Triangulated Irregular Networks 3-D

CAD drawings  Created in CAD can be read by ArcGIS Cannot be edited unless converted

Metadata  Data about data  Who created?  Time relevant?  Coordinate system?  What the fields mean?

Context Menus  Right click on name

Left click on symbol

Right click on symbol

Object Properties

Arc Catalog  ALWAYS used to copy, delete, rename, modify spatial data.  Viewing files

Preview tab  Geography or Table

Metadata  Decode what the information is telling you!!!

ArcToolbox  About 30 tools  Develop your own tools ModelBuilder

Thank you for your time…. I know that it has been a LOOOONNGG day, but you will get to practice, I promise!!!!