spatial database structure

Question 1

database

Answer 1

structured set of data that has a connection or relationship to each other
database may contain both non-spatial and spatial data
GIS directly deals with spatial data

Question 3

advantages of digital databases

Answer 3

multiple access methods
data sharing more efficient
redundancy and costs mininmizes
central control and maintenance
efficient analysis and production of info for decision mkaing

Question 5

data relationships

Answer 5

draw pic slide 7

Question 6

relational (tabular) db model

Answer 6

most common
data is stored in and relationships are created between one or more flat files or tables where each pair of tables has a field in common or key
data extracted using SQL

Question 7

geodatabase model

Answer 7

container of db files
data model uses an object-relational arrangement of the data
2 parts: data types and database schema
types: feature classes, raster datasets and tables
db schema contains info about objects and their relationships

Question 8

querying the db

Answer 8

attributes (non-spatial)
location (spatial)
graphics (geometry)

Question 9

GIS data input sources

Answer 9

keyboard entry: entering values into tables/templates
manual digitizing: digitizing tablet
automatic digitizing: large format scanner
data transfer: data from GPS

Question 10

maps present unique problems

Answer 10

deformation
generalization
artifical errors

Question 11

quality and accuracy standards

Answer 11

data interoperability

Question 12

data source 1: GPS

Answer 12

constellation of earth orbiting satellites maintained by the USA for the purpose of defining geographic positions on and above the surface of the earth

Question 13

3 segments of GPS

Answer 13

space - satellite
control - base stations
user - gps receivers

Question 14

challenges with gps recevier

Answer 14

selective availability
multipath errors
dilution or precision

Question 15

selective avail

Answer 15

us dept of defense distort the satellite time signal reducing positional accuracies

Question 16

multipath errors

Answer 16

signals coming directly from the satellite and reflected off other objects interfere and create location errors

Question 17

dilution of precision

Answer 17

geometry of satellites in the horizon are not equally spread out but clustered

Question 18

data source 2: canadian census

Answer 18

census table
census geog

Question 19

data source 3: open data

Answer 19

avail on web

Question 20

data interoperability

Answer 20

deals with seamless interactions b/w people, data and systems
goal is to share, preserve and manage data, info and knowledge

Question 21

metadata is needed to

Answer 21

identify geospatial resources
exchange
manipulate
catalouge

Question 22

stylesheets

Answer 22

used to format the metadata
determine the layout and other style info aboht the data

Question 23

documenting data quality

Answer 23

location accuracy and precision
attribute accuracy and precision
logical consistency
completeness
data currency
accessibility