Module 7

Question 1

Joined Vs. Related

Answer 1

Join:▪ separate tables can be joined based on the unique identifier, which is shared between each table – in this case the two tables are combined into a new table that contains all of the information of the two separate tables
-▪ joins are very useful for incorporating standalone tables into a GIS analysis

Related:▪ separate tables can be related based on the unique identifier, such that when you select a specific feature in one table, the associated records in the 2nd table are also selected

Question 2

Standalone Tables

Answer 2

▪ standalone tables often do not have explicit spatial coordinate variables, so they cannot be mapped - they contain attribute data but no feature data

Question 3

direction

Answer 3

.you must correctly choose which table to add the 2nd table to

▪ the destination table is the table that will accept the additional attribute data from the other table
▪ the source table is the table containing the information you want to add
-it is important that the destination table contain spatial features so that the newly joined data can be mapped – if you make a standalone table the destination table, there will be no way to map the data

Question 4

many types of relationships between tables, and these are defined by their cardinality: 4 describe each

Answer 4

1. one-to-one cardinality
   - one record in table 1 corresponds with 1 record in table 2 (eg, one table contains census tracts, the other contains unemployment rate)
2. one-to-many cardinality
   - for every record in table 1, there are several records in table 2 (eg, one table contains all of the national parks in Canada, the other table contains individual lakes found in national parks – each national park may have more than 1 lake)
3. many-to-one cardinality
   - each record in the source table could fit into more than one record in the destination table (eg, a table listing the properties of major highways is joined to a table containing city boundaries)
4. many-to-many cardinality
   - several records in 1 table can be related to many records in another table (eg, different soil types can grow more than one type of crop, and different crops can grow in different soil types)

Question 5

Rule of Joining****

Answer 5

there must be one and only one record in the source table for each record in the destination table
-this rule is broken by the “many to one cardinality”

Question 6

we can’t use a join in a many-to-one relationship, but we can use a ______

many-to-many relationship cannot be joined – the most effective way would be to establish several…

Answer 6

relate

many-to-one relationships from the data and then create multiple relates to bring them all together

Question 7

DBMS

Answer 7

tool to find the aspatial data and where it is stored

Question 8

the ______ in ArcGIS is the primary tool

for database management

Answer 8

Catalog

Question 9

3 main Steps in using a Data Management System

Answer 9

1. Data Entry
2. Verification(checking data vs. original source)
3. Updates

Question 10

multiple membership

Answer 10

where an individual can

exist in more than one group and potentially at more than one level

Question 11

______ data structure cannot handle multiple membership data connections

Answer 11

hierarichal

Question 12

relational databases

Answer 12

relational databases are one of the paradigm shifts
that redefined how DBMS’s could be built
▪ the relational model uses many tables that contain
unique levels of attribute data, but the individuals in
the tables are linked by some unique identifier

Question 13

GIS Summarize function

Answer 13

▪ the summarize function is useful for performing

statistical analysis on groups of data

Question 14

in a raster the count field in the atribute table is..

Answer 14

a count field that displays how many raster cells are of each code – the count field can be thought of as an area field as well, since you know the cell dimensions (eg, 30 x 30 m)

Question 15

clip and erase tools

Answer 15

clip would keep everything within the clip shape

erase would erase everything within the shape

Question 16

object-oriented database

Answer 16

the object-oriented database allows the user to specify both the structure of the objects and the processes that can be applied to them, such that:
▪ the ‘state’ of an object is the set of values of its attributes, and the ‘behaviour’ represents how those attributes might change

.object-oriented databases are potentially more appropriate for geographic data
than the relational model, since they allow for the modeling of complex, real-world
objects, does not distinguish between spatial and attribute data, and is appropriate
for graphics operations

Question 17

The ______ database type is the best for GIS because…3

Answer 17

.object-oriented databases are potentially more appropriate for geographic data
than the relational model, since they allow for the modeling of complex, real-world
objects, does not distinguish between spatial and attribute data, and is appropriate
for graphics operations

– the packaging together of the description of state and behaviour
in each object
– the ability to re-use some or all of the characteristics of one object
in another object
– the specific implementation of operations like draw, create, or
delete for each object

Question 18

faults of the object oriented databases

Answer 18

▪ since many geographic ideal have implicit uncertainty and the spatial objects
that we require our databases to model are often the products of interpretation
or generalizations, it can be difficult to represent the world as rigidly bounded
objects
▪ the methods of creating object-oriented models are in their infancy and much
work is need to simply implement them, either practically or theoretically