data aq

in RDBMS a table is called a

Relation

What does RDBMS stand for

Relational Database Management System

Primary Data

Collected in digital format specifically for GIS

Secondary Data

data adapted for use in GIS

Data is

observations made from monitoring real world,

often numbers

Information is

data with meaning and context added

Knowledge is

information that helps in drawing

conclusions

What are the dimensions of data

temporal, thematic (descriptive info), spatial

Keycoding

keyboard entry used for attribute tables only available on paper

Analogue data encoding includes

Keycoding, digitizing of paper maps, scanning

File format reading can happen 3 ways

translation, on the fly, natively

How does file translation work in gis

format is converted externally to vendors own format

• Usually requires user to carry out conversion prior to use of data

how does on the fly file processing work in GIS

conversion is accomplished internally and “automatically”

• No user action needed, but usually no ability to change data

how does native/transparent file processing work in GIS

normally implies

• No special user action needed

• ability to read and write (change or edit) the data

data interoperability

Move data across format barriers

ArcGIS Interoperability Extension

an integrated spatial extract, transform, and

load (ETL) toolset that runs within the geoprocessing framework. Spatial ETL tools

are user-created geoprocessing tools that can transform data between different data

models and different file formats.

Geocoding

refers to the process of assigning spatial locations to data that are in

tabular format but have fields that describe their locations.

address matching

most common type of geocoding, plots street addresses as point features

geosearch

find and display addresses, places, etc

batch geocoding

uses a locator to find multiple places at once

reverse geocoding

turns coordinates into place name or addy

ReGRID

Nationwide parcel map in Living Atlas

ArcGIS Hub

Where organization creates open data sites

GeoJSON

open standard format represents geographical features with attributes, stores CRS and coordinates for web based mapping

What does a .shp do

hold geometry

what does a .shx do

hold indices

what does a .dbf stand for and do

Database table, holds attributes

what does a .prj do

projection info

other optional data files in a shapefile include

Ancillary files (*.sbn, etc)

Metadata files (*.htm, .xml, .txt)

Parts of a Shapefile

A feature dataset contains

feature classes

Metadata is FAIR

Findable, accessible, interoperable, usable

Natural Data

represent natural real world features

Artificial Data

Represents artificial features like utilities and infrastucture

Planimetric Data

features that have a physical manifestation in the real world

Cadastral Data

Politically or legally defined by not visible, like parcels

Discrete Data

Data that are limited to a finite number

of potential values.

Continuous Data

Data that can take on an infinite number of

potential values

Nominal Data

names objects, but does not allow

comparisons between the different objects

Classified, e.g. land use, soils map

Ordinal Data

Ranked (classification based on a single spectrum

representing a single set of circumstances) , eg road type, school district ranks

Interval Data

Relative, ZEROES MEAN SOMETHING, like temperature, pH

Ratio Data

Absolute, ZERO MEANS NOTHING, length, height, rainfall concentration

Integer cell values are best for

representing categorical (discrete) data

Floating point cell values are good to represent the

Continuous Surfaces

Hybrid data models include

Geodatabase (esri proprietary) and Geospatial PDF (portable document format from Adobe), Geopackage (Open source), KML (Google Earth)

What is a Record?

A row on a table

What is a field?

A column on a table

What is an attribute value?

A cell in a table

Precision in a data structure is

Number of significant digits allowed

Scale in a data structure is

Number of decimal places allowed

What does BLOB stand for

Binary Large Object

What does GUID stand for

Globally Unique Identifier

When did databases begin to be used

1960s

What is a database model

a set of constraints that describe the organization of

data

Flat Database

A spreadsheet whereby all data are stored in a single, large table

Hierarchical Database

Composed of records that are connected by links, 1:M

Hierarchical Database Example

Network Database

Client server architecture that Reduces redundancy, 1:M or M;M, faster processing and better search

Network Database Example

Relational Database

Dominates GIS, series of tables linked by keys

In relational databases a table is called a

Relation

In relational database a row is called a

tuple

In a relational database a column is called an

attribute

Relational Database advantages

tables separately prepared, maintained, reduces redundancy

DBMS

Controls storage, retrieval, maintenance, and modification of large datasets, Allows users to deal with data without having to understand storage and

structure of database

DBMS is accessed through

SQL, Microsoft Access

First RDBMS was built when and where

at MIT in the early 1970s

What is RDBMS

A software package that records information in such a way that data can be accessed without reorganization of the tables

database schema meaning

DEFINES THE PHYSICAL
STRUCTURE ALONG WITH RULES, RELATIONSHIPS, AND
PROPERTIES OF EACH DATASET WITHIN THE GEODATABASE

what is a schema report

A human readable Excel, JSON, PDF, or HTML report detailing how the geodatabase schema is defined.

should you define PKs (primary keys) when not required?

yuh

3 rules of tidy data

Each variable forms a column, and contains values.

• Each observation forms a row.

• Each type of observational unit forms a table.

Wickham’s third rule of tidy data aligns with

the relational database model, because it reduces redundancy

What does Relate do

Pointer between related datasets, defined as a layer property.

What does a Join do

Appends origin dataset with destination dataset

Advantage of Relate

Improved editing performance

Advantage of Join

good for labeling and symbology

Cardinality is

one-to-one, one-to-many, many-to-one, or many-to-many

1:1

Every feature has exactly one related record in the other table

1:M

Features in one table may have more than one related record in the other table

M:1

Multiple features in one table have one related record in the other table

M:M

Multiple features in one table have multiple records in another

Relate supports what cardinalities

One to many and many to many, it defines the link between datasets

Join supports what cardinalities

One to One and Many to one.

Relationship classes support what type of cardinality

All types, and related objects update automatically

Comparing relationships

What is an Aspatial query

Select by attribute

What is SQL

(Structured Query Language) is commonly used computer language

developed to query attribute data within a RDBMS

What is a clause

A grammatical unit in SQL and a language element that includes Select, From, Where, Order By, Having

Select clause

denotes what attribute table fields you wish to view

From clause

denotes the attribute table in which the information resides.

Where clause

denotes the user-defined criteria for the attribute information that must be met in order to be included in the output set

Order By Clause

denotes the sequence in which the output set will be displayed.

Having clause

denotes the predicate used to filter output from the ORDER BY clause.

Relational SQL operator

A construct that tests a relation between two entities using symbols like < or >

Arithmetic SQL operator

Include mathematical functions such as addition (+), subtraction (-), multiplication

(*), and division (/

Boolean SQL operator

A construct that performs a logical comparison

• Include the statements AND, OR, XOR, and NOT

What is XOR

either/or

4 types of spatial query

Distance, Containment, Intersection, Adjacency