Download - ArcView Training - 7-15-2011
ArcGIS 9.3.1
Basic Concepts
Technology makes life easier.
Disclaimer
• The following presentation is not endorsed by any creature, human or otherwise, living or dead.
• The presenter is barely qualified to tie his own shoe.
• If the following presentation causes you any grief, now or later, the presenter will provide you with a full refund.
• By watching this presentation you hereby forfeit any right to criticize the presenter or the presentation.
Mappers used to have a fancier name.
Part 1
Cartographers: (n)People who make maps.
Landmen: (n)People who like to look at maps.
• ArcGIS is very complex.• Luckily, a landman doesn’t
need to know as much about ArcGIS as a mapper.
• Nevertheless, a modern landman should be comfortable using ArcGIS.
Technophobia
Part 2
A
B
Lumberjack
A
B
Farmer
Landman
A
B
Technology makes life easier.
The secret life of data
Part 3
What is data?• Abstractions, or simplified
descriptions, of reality.
Types of data• Qualitative
– Color, shape• Quantitative
– Number, height, weight, length
Geographical data• Cartesian Coordinates, Lat./Long.,
physical address
Communicating data• The same data can be
expressed in different ways.• The clear communication of
data is as important as the data itself.
101
Base Ten Binary
0 01 1
2 103 114 1005 1016 110
Conclusion:• The “best” way to display data
depends on the end user’s needs.• ArcGIS is a database
management system that allows users to capture, display, and analyze data in multiple ways.
What the heck is a database anyways?
Part 4
Database:• A database is simply a
collection of data.
Simplest database• Flat database
– A table, array, or list• 2-dimensional array
–Rows and columns–Rows contain “records” –Columns contain similar data
about each record• Excel spreadsheet
Database Management System (DBMS):
• A DBMS is a collection of data and routines to perform operations on that data.
Example database operations• Query• Sort• Statistical operations• Joins and relates
– Primary key– Called an FID in ArcGIS
Junk in, junk out• A collection of unorganized,
unrelated data, is practically useless.
Relational Database• A collection of data grouped by
common attributes.– Example: All the oil and gas leases
in Karnes County covering more than 500 net acres.
Multi-table Relational Database
Units
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Leases
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Wells
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Surface Tracts
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Relates
Joins
ArcGIS can display the same data in more than one way
• Maps• Tables• Reports
Lease
Provisions
Thematic Map
Table
Report
Summary:• ArcGIS is a relational database
management system that allows users to capture, display, and analyze data in multiple ways.
• Its strength is in dealing with data related to specific positions in space, called georeferenced data.
• Georeferenced data– Data associated with a specific place on
earth.
Georeferenced data
Part 5
Georeferencing: • The science of showing the relationship
between data and its position on earth.• We accomplish this by using a
coordinate system.– Data + coordinates = georeferenced data
Elements of a coordinate system–Ellipsoid, datum, projection,
units.
Ellipsoid• A good enough model of the earth.• There’s more than one model.• Provides us with a frame of reference in which to
locate features on Earth.
Datum• A set of benchmarks from which
measurements on Earth are made.• Global datum
– NAD 83– WGS 84 (GPS)
• Local datum– NAD 27– Meades Ranch, KS
• Differences in accuracy
Local datums
Not Good Better Even Better
Projection• How to get a 3D Earth onto 2D paper.• Distortions
Units• Feet or meters.
– NAD 27 is typically in feet– Global datums are typically in meters
NAD 27, Texas South Central (4204), feet
Re-projecting layers• If you combine map layers created
with different coordinate systems, they will not line-up.
• ArcGIS re-projects layers on the fly.
Conclusion:• A coordinate system allows us to
relate data to places on Earth using a commonly accepted system of location.
• This georeferenced data can be stored, analyzed, and communicated in a concise, efficient manner.
All this talk about layers
Part 6
ArcMap supports layering
Units
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Leases
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Wells
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Surface Tracts
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Map layers are a depiction of the multiple tables in a map
Map layers• Vector
– ESRI shapefiles• Geometric shapes: Points, lines,
polygons, polylines• Raster
–Aerial photographs
ESRI shapefiles• 6 different files combine to make a shapefile
Shapefile parts• Geometry (.shp)
–Points, lines, polygons, polylines• Attributes (.dbf)
–Tabular data• Projection (.prj)
–Coordinates
Attributes (.dbf)• The data behind the shapes• Can be exported to a dbase file, which can be opened in Excel.
Raster data• Aerial photos must be georeferenced and in the same projection
as the other map layers
Getting started with ArcGIS
Part 7
ArcGIS is a combination of programs• ArcCatalog
–Manage layers and sources–Create new, empty layers
• ArcMap–View and edit data
Menu barTool bar
File tree
Contents pane
ArcCatalog
Menu barTool bar
Table of Contents
Drawing toolbar
Display area
ArcMap
Maps
Data Frames
Layers
Map Features
Maps contain Data Frames.
Data Frames contain Layers.
Layers contain Map Features.
Each geometric, or vector, map feature in a layer also has a record in the attribute table for that layer.
Primary Key
Lease layer Lease attribute table
Static data– Layers saved to your
desktop
Dynamic data– ArcSDE
ArcSDE• How to provide map data on a multi-user system.• SDE layers live on a server. They can only be edited
by users with editing rights.