Glossary for Geospatial Science

expression: A line in a query or script that compares values.� An expression evaluates to �true� (1) or �false� (0).� Example: numlines < 3.� It compares the numlines variable for the current node element with the number 3.� The expression is true only if the value of numlines is less than three.� Also, an expression can evaluate to a number (for example: 2*YIELD).� If such an expression is used where true and false values are needed, 0 is treated as false, and anything else is treated as true.