Podcast
Questions and Answers
What is meant by geospatial data?
What is meant by geospatial data?
- Data that can only be used in urban planning
- Data with locational information such as coordinates and addresses (correct)
- Data obtained only from field surveys
- Data that lacks geographic elements
Which method is considered a primary GIS data capture technique?
Which method is considered a primary GIS data capture technique?
- Manual digitizing
- Vectorization
- Differential Global Positioning System (DGPS) (correct)
- Scanning paper maps
What is an advantage of the raster data capture method?
What is an advantage of the raster data capture method?
- It allows for cost-effective and organized data collection (correct)
- It provides highly detailed physical maps
- It guarantees the fastest data capture
- It is the only method that requires physical surveying
Which method falls under secondary GIS data capture techniques?
Which method falls under secondary GIS data capture techniques?
What distinguishes primary GIS data capture from secondary methods?
What distinguishes primary GIS data capture from secondary methods?
What technique uses aerial photographs for data capturing?
What technique uses aerial photographs for data capturing?
Which of the following is NOT a source of geospatial data?
Which of the following is NOT a source of geospatial data?
What is a disadvantage of the vector data capture method?
What is a disadvantage of the vector data capture method?
What are the two main types of operations involved in data manipulation?
What are the two main types of operations involved in data manipulation?
What is the purpose of data output in a GIS?
What is the purpose of data output in a GIS?
Which step is NOT part of the general procedure for a GIS project?
Which step is NOT part of the general procedure for a GIS project?
What is one of the main sources of spatial data errors in GIS analysis?
What is one of the main sources of spatial data errors in GIS analysis?
Which category of error includes mistakes resulting from natural variations?
Which category of error includes mistakes resulting from natural variations?
What practice does data management emphasize?
What practice does data management emphasize?
What is required for effective data management?
What is required for effective data management?
What constitutes the manipulation process in GIS?
What constitutes the manipulation process in GIS?
What is the primary purpose of digitizing in relation to raster data?
What is the primary purpose of digitizing in relation to raster data?
What are the two main types of data to be entered into a GIS?
What are the two main types of data to be entered into a GIS?
Which device is NOT commonly used for data input in GIS?
Which device is NOT commonly used for data input in GIS?
Which statement is true regarding geographic reference data?
Which statement is true regarding geographic reference data?
What characterizes manual data input in GIS?
What characterizes manual data input in GIS?
What is a key advantage of digitizing data for development planning purposes?
What is a key advantage of digitizing data for development planning purposes?
How is data storage structured in GIS?
How is data storage structured in GIS?
What does data manipulation and processing involve in GIS?
What does data manipulation and processing involve in GIS?
Flashcards
Geospatial Data
Geospatial Data
Data with geographic information, like coordinates or addresses.
Primary GIS Data Capture
Primary GIS Data Capture
Capturing data directly using surveying methods (raster/vector).
Raster Data Capture
Raster Data Capture
Capturing data without physical contact, e.g., satellite imagery.
Vector Data Capture
Vector Data Capture
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Secondary GIS Data Capture
Secondary GIS Data Capture
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GIS Data Capture
GIS Data Capture
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Field Survey Data
Field Survey Data
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Data Sources
Data Sources
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Raster Data Scanning
Raster Data Scanning
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Digitizing
Digitizing
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Data Input (GIS)
Data Input (GIS)
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Manual Data Entry
Manual Data Entry
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Geographic Reference Data
Geographic Reference Data
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Attribute Data
Attribute Data
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Data Storage in GIS
Data Storage in GIS
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Data Manipulation & Processing
Data Manipulation & Processing
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Data Manipulation
Data Manipulation
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GIS Data Output
GIS Data Output
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GIS Project Procedure
GIS Project Procedure
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Data Management
Data Management
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Data Errors in GIS
Data Errors in GIS
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Sources of Data Errors
Sources of Data Errors
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Data strategy
Data strategy
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Data Management Skills
Data Management Skills
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Study Notes
Chapter 5 Outline
- Geo spatial data
- Data capturing and data entry
- Sources of spatial data errors and its correction measures
What is Geospatial Data?
- Geospatial data has a geographic component.
- Data records include location information like coordinates, addresses, city, or ZIP codes.
- GIS data is a type of geospatial data.
Source of Data
- Field survey data
- Existing tabular data and maps
- Remote sensing data
- Aerial photographs and satellite imagery
- Soft ideas/ undocumented knowledge
Data Capture
- GIS data capture is a method to digitize map attributes, facilities, resources, and organizational information into a GIS system's layers.
- Two types of methods are commonly used
- Primary GIS Data Capture Method
- Secondary GIS Data Capture Method
Primary GIS Data Capture Method
- Uses surveying technologies like raster and vector data capture.
Raster Data Capture Method
- Captures attributes and data without physical contact.
- Often uses satellite imagery and aerial photography.
- Offers consistency and organization for accurate, cost-effective data.
Vector Data Capture Method
- Involves physical surveying techniques like DGPS and ETS.
- Though effective, it is often time-consuming and expensive.
Secondary GIS Data Capture Method
- Employs technologies such as scanning, manual digitizing, vectorization, photogrammetry, and feature construction to capture data.
- Scanning raster data: high-resolution scanners provide accurate raster images from hard copies, which can be georeferenced and digitized.
- Digitizing: the process of entering digital codes of analyzed data into a computer; can be manual (using digitizing tablets) or automatic (using scanners).
Data Entry
- Data input is encoding data into a computer format and recording it in the GIS database.
- Two types of data are entered in a GIS: spatial (geographic location of features) and non-spatial (descriptive or numeric details).
- Data input types include manual entry, digitizing, and scanning.
Data Storage
- Data organization within a GIS system, considering spatial and attribute data by their location and interrelationships.
- Spatial data is often stored on hard drives or diskettes.
Data Manipulation and Processing
- Data manipulation and processing provide useful information from existing data.
- Two types of operations include:
- Editing data to remove errors and update data sets
- Analytical operations to answer specific questions.
Data Output
- Display or presentation of data in various formats, including maps, graphs, reports, tables, and charts.
- Data can be output as hard copies, screen displays, or text files for further analysis in other programs.
Data Management and Analysis
- Used to facilitate data input, storage, management, retrieval, analysis, and presentation.
- The general procedure involves:
- Determining the objectives of a GIS project
- Designing the database
- Building or creating a GIS database
- Entering data
- Analyzing data
- Presenting results/information
Data management
- Data management involves securely, efficiently and cost-effectively collecting, keeping and using data.
- This includes the process of ingesting, storing, organizing and maintaining data.
- Data management effectively requires a data strategy and dependable methods to access, integrate, cleanse, manage and prepare data for analysis.
- Data management skills involve the abilities to effectively manage and use information.
Errors in GIS Data
- Errors can be introduced at many points in GIS analysis, with data collection being a major source.
- Each new dataset introduces potential errors.
- Understanding data quality is essential due to the diverse sources of data.
- Errors are categorized by Burrough (1986) into:
- Obvious sources of errors
- Errors from natural variations or original measurements
- Errors during processing
Errors Arising During Processing
- These errors are the hardest to detect, demanding specific knowledge of information systems.
- These errors can occur in various ways and in multiple sets which makes them potentially more insidious in GIS projects.
General Sources of Error in GIS Data
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Conception
-
Measurement
-
Representation
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Analysis
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GIS data errors can be corrected through careful data collection and editing.
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Good data management techniques helps to manage errors.
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Description
This quiz covers the essentials of geospatial data, including its definitions, sources, and methods of data capture. Explore the intricacies of acquiring data for geographic information systems (GIS) and understand the types of errors that can occur. Perfect for students or professionals looking to deepen their knowledge in geospatial technology.