Outline Chapter 1 Introducing ArcGIS What is GIS? Some GIS applications Introducing the ArcGIS products How does GIS work? Basic data formats The ArcCatalog interface 1-1 1-2 A history of products Arc/Info ArcGIS What is ArcGIS? Arc ArcPlot ArcGIS Desktop ArcMap Description and history of the ESRI GIS family ArcEdit Info/Tables GRID ArcView 3x ArcCatalog ArcToolbox ArcInfo Workstation 1-3 Coverages Shapefiles Geodatabases 1-4 1
ArcGIS Desktop ArcGIS functionality ArcView 8 ArcEditor ArcInfo ArcCatalog ArcMap ArcToolbox 1-5 Three levels of functionality and cost 1-6 Spatial Analyst 3D Analyst Publisher/ArcReader Network Analyst Maplex Geostatistical Analyst ArcGIS Extensions Extensions are additional tools and commands that can be added to the core ArcGIS interface Appear as new toolbars and toolsets in ArcCatalog How does GIS work? Data storage The ArcGIS Interface 1-7 1-8 2
Cartographic Model Map-like layer 1-9 1-10 Feature GIS data models Lake Entity Spatial Object Symbol Vector model Raster model 1-11 1-12 3
GIS Data Polygon Vertices Features are stored as a series of x-y coordinates in a rectangular coordinate system. Points Line Y X Nodes 1-13 Some familiar coordinate systems can be found on a topo map. X-Y Coordinate systems/units: Longitude-latitude (degrees) State Plane (feet) UTM (meters) 1-14 Features linked to data Feature classes Each feature is linked to an entry in a data table containing information about the feature. A collection of similar objects with the same attributes States feature class Cities feature class 1-15 1-16 4
Advantages of vectors Precise location of features Storing many attributes Flexible for cartography Compact storage of information Ideally suited for certain types of analysis, especially areas, lengths, connections The raster data model X, Y location Columns Raster data file N rows by M columns Rows X, Y location Georeferenced to earth s surface 1-17 1-18 Types of raster data Continuous data Discrete raster: land use Discrete raster: roads Continuous raster: DEM Continuous raster: image 1-19 Raster is the best way to store continuously changing values such as elevation Analysis faster and more flexible than vectors for many applications Some analysis only possible using rasters 1-20 5
Raster analysis functions Impact of resolution Density Least cost path Distance Interpolation 90m resolution 10m resolution Storage space increases by the square of the resolution Portraying large areas at high precision is problematic Viewshed Buffers 1-21 1-22 Storage of attributes The ArcGIS Interface Menu bar Roads may have other attributes: ownership, speed limit, number of lanes, etc. Would need a new raster for each attribute Context menu Tool bars Tear-off/dock Raster contains 1 value indicating a single attribute road type for example Only numeric attributes may be stored More toolbars Display window 1-23 1-24 6
The Tools toolbar 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Context menus Right-click name Zooming and panning Full extent Pointer tool Identify attributes of features Find text in attributes Measure distances Left-click symbol Right-click symbol Menus pop up when certain objects are clicked 1-25 1-26 Spatial data file Associated properties Held in memory in ArcMap Used as inputs to functions/tools May be saved as a file What is a layer? Layer Properties Property tabs 1-27 1-28 7
Data formats Important Coverages Shapefiles Geodatabases 1-29 Although Windows permits spaces in file and folder names, in GIS they are a BAD IDEA. They often work, but sometimes a certain program or function will fail if it encounters a space in a folder name. Real GIS users FLINCH when they see spaces anywhere in folder/file names even when they re allowed! 1-30 Topology Information and rules stored about spatial relationships between features and feature classes A dangle error the two lines fail to connect B overlap gap A Polygon errors Correct topology Polygon A is composed of a label and two arcs. Polygon A is adjacent to polygon B and shares one common arc. Selfintersecting loop error 1-31 1-32 8
Topology rules Shapefiles in Windows Explorer Shapefiles Coincident boundary Shannon County Bennett County Topology rules establish how features should be spatially related. Pine Ridge Indian Reservation South Dakota Nebraska These three layers show several topology errors. Topology rules may apply within a layer or between layers. No gaps or overlays between counties The Pine Ridge and Bennett County boundaries should match The South Dakota and Pine Ridge boundaries should match 1-33 Shapefiles in ArcCatalog One feature class Multiple files Simple features No topology Dbf tables From ArcView 1-34 Coverages Geodatabases Single file Multiple feature classes Multiple feature classes Topological features Many files Info tables From Arc/Info Access database technology Feature datasets Simple and topological features Validation rules Customized object behavior New to ArcGIS 1-35 1-36 9
Other types of data Metadata Rasters Layer files Tables CAD Drawings Contains information about data that people need to properly understand and use the data Created with and copied with data 1-37 Fig. 22. The metadata toolbar lets you create, view, and edit metadata for your layers. Create Edit Update Import Export 1-38 Geoprocessing Stringing together commands and analysis functions to achieve a result Menus Tools Command line Model builder Scripts AVOID SPACES IN FOLDERS and FILENAMES Spaces are Evil 1-39 1-40 10
Connecting to folders The ArcCatalog Interface Menu/tool bars 1-41 Folder tree Display window 1-42 Three view modes Tables in ArcCatalog Contents Preview Metadata 1-43 1-44 11
Getting Statistics File Properties Right-click file name 1-45 1-46 Did I mention that you should avoid spaces in folder and file names? 1-47 12