gis overlay and geoprocessing

Question 1

geoprocessing

Answer 1

analysis of spatial data layers, such as dissolving, intersecting and merging. A GIS operation used to manipulate GIS data. A typical geoprocessing operation takes an input dataset, performs an operation on that dataset, and returns the result of the operation as an output dataset. Common geoprocessing operations include geographic feature overlay, feature selection and analysis, topology processing, raster processing, and data conversion. Geoprocessing allows for definition, management, and analysis of information used to form decisions.

Question 2

map overlay

Answer 2

to combine two spatial data layers either for display or to evaluate the relationships between them. A spatial operation in which two or more maps or layers registered to a common coordinate system are superimposed, either digitally or on a transparent material, for the purpose of showing the relationships between features that occupy the same geographic space.
[analysis/geoprocessing] In geoprocessing, the geometric intersection of multiple datasets to combine, erase, modify, or update features in a new output dataset.

Question 3

clip

Answer 3

A command that extracts features from one feature class that reside entirely within a boundary defined by features in another feature class.

Question 4

erase

Answer 4

In ArcInfo, a command that removes or deletes features from one coverage that overlap features in another coverage. Overlay function tht removes features lying inside the external boundary of another polygon feature class

Question 5

intersect

Answer 5

an operation to overlay two spatial data layers and find the the areas common to both while discarding areas unique to either. A geometric integration of spatial datasets that preserves features or portions of features that fall within areas common to all input datasets.

Question 6

union

Answer 6

operation to create a new feature or set of features by combining all the areas from two inout layers. A topological overlay of two or more polygon spatial datasets that preserves the features that fall within the spatial extent of either input dataset; that is, all features from both datasets are retained and extracted into a new polygon dataset.

Question 7

sliver

Answer 7

small polygon created during map overlay due to slight boundary differences in the inputs; usually considered an error. A small, narrow, polygon feature that appears along the borders of polygons following the overlay of two or more geographic datasets. Sliver polygons may indicate topology problems with the source polygon features, or they may be a legitimate result of the overlay.

Question 8

XY tolerance

Answer 8

setting used for geoprocesing that defines the minimum allowable distance between vertices

Question 9

dissolve

Answer 9

combine features together when they share the same value for an attribute

Question 10

buffer

Answer 10

delineated area within a specified distance of a feature

Question 11

append

Answer 11

a function that combines features from two different feature classes

Question 12

merge

Answer 12

combine two or map features into one feature or combine two or more data layers into one

Question 13

ArcToolbox

Answer 13

set of functions and commands for processing spatial data

Question 14

Model Builder

Answer 14

graphical interface used to combine existing tools to create new tools and scripts

Question 15

script

Answer 15

a program including ArcGIS commands and functions

Question 16

Environment settings

Answer 16

program level or tool level stings that impact how tools run or set characteristics of the output such as cell size or coordinate system

Question 17

parameters

Answer 17

specific values associated with map projections that define how it appers; variables that serve as inputs to models