Mid-Semester Lecture Exam Vocabulary Obvious steps within GIS –Selection and query processes –Working with tables –Classification concepts Projections –What are they – what do they change –Coordinates – how are they relevant

Home Work 1 In ArcToolBox –Coversion Tools Import to coverage –Import from interchange file Define projection for coverage In ArcMap –Data Export to shapefile Project shapefile to whatever you want Dealing with an exchange format

Data types – raster vs. vector How does GIS differ from a mapping or CAD package The three basic components of ArcGIS Define vs Projection Metadata More questions about coordinates –What information is critical for a coordinates to be relevant? Cardinality When do you use a join and when relate?

Tables Continued Adding Fields and Records

There are several data types There are two basic types common used: Text Data Numeric Data Left JustifiedRight Justified

Data Types TextDateShortLongBLOBFloatDouble Smith 10/06/ It is very important to choose the right data type.

ArcGIS can handle several tabular data formats: Coverages use an INFO format. These are an older format, cumbersome, but still frequently used. A shapefile uses a.dbf format. Much more sophisticated than an INFO file. We are currently using.dbf files in the lab exercises. Geodatabases uses a RDBMS format. Very sophisticated and powerful but more complex. We will use them in a few weeks time.

Very often you need a new field in a table.

Specify the Name and the Data Type -32,000 to +32, billion to + 2 billion Integers – No Decimals

Precision is the number of digits to be stored. Scale is the number of decimal places. Numbers with Decimal Places

Date Text It is important to specify a length to accommodate your attribute but not too long.

Calculating a Value

The selected records are assigned the calculated value Notice that text values are enclosed in double quotes

Calculating a Numeric

Convert from one data type to a different data type Text type Numeric type

Add a new numeric FIPS field then calculate the text field as a numeric field.

Create a New Table

Open the new table in ArcMap and then add data

You can use ascii files