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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
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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
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!!!!