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Web GIS. MCQ




Certainly! Here are 100 multiple-choice questions (MCQs) along with their answers on the topic of web GIS:

1. What does GIS stand for?
   a) Geographic Information System
   b) General Information System
   c) Graphical Information System
   d) Global Information System
   Answer: a

2. What is the primary purpose of web GIS?
   a) Data visualization
   b) Data analysis
   c) Data storage
   d) Data sharing
   Answer: d

3. Which technology is commonly used for web GIS?
   a) HTML
   b) Java
   c) JavaScript
   d) Python
   Answer: c

4. Which component is essential for web GIS?
   a) GPS
   b) Internet connection
   c) Satellite imagery
   d) Desktop computer
   Answer: b

5. What is a web map?
   a) A map created using web technologies
   b) A map printed from a web page
   c) A map displayed in a web browser
   d) A map downloaded from the internet
   Answer: c

6. Which programming language is commonly used for web mapping?
   a) C++
   b) PHP
   c) HTML
   d) JavaScript
   Answer: d

7. Which software is commonly used to build web GIS applications?
   a) ArcGIS
   b) AutoCAD
   c) QGIS
   d) Google Earth
   Answer: a

8. Which file format is commonly used for web mapping?
   a) CSV
   b) PDF
   c) TXT
   d) GeoJSON
   Answer: d

9. What is a basemap in web GIS?
   a) A map showing geographical features
   b) A map used as a background for other data layers
   c) A map created using aerial imagery
   d) A map created using satellite imagery
   Answer: b

10. What is geocoding in web GIS?
    a) The process of converting addresses into geographic coordinates
    b) The process of converting geographic coordinates into addresses
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

11. What is a web feature service (WFS)?
    a) A service that provides access to geospatial data
    b) A service that provides access to satellite imagery
    c) A service that provides access to basemaps
    d) A service that provides access to geocoding services
    Answer: a

12. Which of the following is an example of a web GIS application?
    a) Google Maps
    b) Microsoft Word
    c) Adobe Photoshop
    d) Spotify
    Answer: a

13. What is a web service in the context of web GIS?
    a) A software application that provides access to geospatial data or functionality
    b) A website that allows users to download maps
    c) A social media platform for sharing geospatial data
    d) A tool for analyzing geospatial data
    Answer: a

14. What is a spatial query in web GIS?
    a) A query that involves spatial relationships between geographic features
    b) A query that retrieves data based on non-spatial attributes
    c) A query that retrieves data based on temporal attributes
    d) A query that retrieves data based on alphabetical order
    Answer: a

15. Which of the following is an example of a web GIS data format?
    a) Shapefile
    b) MP3
    c) Excel spreadsheet
    d) JPEG image
    Answer: a

16. Which technology allows web GIS applications to display dynamic data?
    a) AJAX
    b) FTP
    c) SMTP
    d) HTTP
    Answer: a

17. What is a geoprocessing service in web GIS?
    a) A service that performs spatial analysis operations on geospatial data
    b) A service that converts addresses into geographic coordinates
    c) A service that provides access to satellite imagery
    d) A service that allows users to create web maps
    Answer: a

18. What is a mashup in web GIS?
    a) A combination of different web services to create a new application
    b) A map created using satellite imagery
    c) A map displayed in a web browser
    d) A tool for analyzing geospatial data
    Answer: a

19. Which of the following is an example of a web GIS data source?
    a) OpenStreetMap
    b) Netflix
    c) Instagram
    d) Amazon
    Answer: a

20. What is a web mapping API?
    a) A set of programming instructions that allows developers to embed maps into web applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

21. What is the purpose of a legend in a web map?
    a) To provide information about the map's data layers and symbols
    b) To display the latitude and longitude coordinates
    c) To indicate the scale of the map
    d) To display the title of the map
    Answer: a

22. What is a spatial index in web GIS?
    a) An optimized data structure that improves the speed of spatial queries
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

23. What is a web map service (WMS)?
    a) A service that provides access to geospatial data as images
    b) A service that provides access to geocoding services
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

24. What is a heat map in web GIS?
    a) A map that shows areas of high and low temperatures
    b) A map that shows the density of certain geographic phenomena using color gradients
    c) A map that shows the location of earthquakes
    d) A map that shows the elevation of the land surface
    Answer: b

25. What is a web GIS portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for sharing photos with friends and family
    c) A website for streaming movies and TV shows
    d) A website for online shopping
    Answer: a

26. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for measuring distances between geographic features
    Answer: a

27. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social media platforms
   

 c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

28. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

29. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

30. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

31. Which of the following is an example of a web mapping library?
    a) Leaflet
    b) Photoshop
    c) Excel
    d) Spotify
    Answer: a

32. What is a web GIS application programming interface (API)?
    a) A set of programming instructions that allows developers to interact with web GIS services and data
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

33. What is a geocoding service in web GIS?
    a) A service that converts addresses into geographic coordinates
    b) A service that converts geographic coordinates into addresses
    c) A service that provides access to basemaps
    d) A service that provides access to geospatial data
    Answer: a

34. What is a web mapping server?
    a) A server that provides geospatial data and services to web mapping applications
    b) A server that provides access to satellite imagery
    c) A server that provides access to basemaps
    d) A server that provides access to geocoding services
    Answer: a

35. What is a geospatial web portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for social networking
    c) A website for online shopping
    d) A website for streaming movies and TV shows
    Answer: a

36. What is a web GIS client?
    a) A software application that allows users to access and interact with web GIS services
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

37. What is a tile map in web GIS?
    a) A map that is divided into small image tiles for efficient display and navigation
    b) A map that shows the locations of all the tiles in a web GIS application
    c) A map that displays real-time traffic information
    d) A map that displays the locations of all the web mapping servers
    Answer: a

38. What is a geospatial web application?
    a) An application that provides access to geospatial data and services through the internet
    b) An application for creating 3D visualizations of geographic data
    c) An application for converting raster data into vector data
    d) An application for measuring distances between geographic features
    Answer: a

39. What is a geospatial web server?
    a) A server that provides geospatial data and services to web GIS applications
    b) A server that provides access to social media platforms
    c) A server that provides access to basemaps
    d) A server that provides access to satellite imagery
    Answer: a

40. What is a web GIS framework?
    a) A software framework that provides tools for building web GIS applications
    b) A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for analyzing geospatial data
    Answer: a

41. What is a geospatial web viewer?
    a) An application that allows users to view and interact with geospatial data through the internet
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

42. What is a geospatial web service interface?
    a) An interface that allows applications to access and use geospatial web services
    b) An interface that allows applications to convert addresses into geographic coordinates
    c) An interface that allows applications to convert geospatial data into a different format
    d) An interface that allows applications to measure distances between geographic features
    Answer: a

43. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

44. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social media platforms
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

45. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

46. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

47. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

48. Which of the following is an example of a web mapping library?
    a) Leaflet
    b) Photoshop
    c) Excel
    d) Spotify
    Answer: a

49. What is a web GIS application programming interface (API)?
    a) A set of programming instructions that allows

 developers to interact with web GIS services and data
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

50. What is a geocoding service in web GIS?
    a) A service that converts addresses into geographic coordinates
    b) A service that converts geographic coordinates into addresses
    c) A service that provides access to basemaps
    d) A service that provides access to geospatial data
    Answer: a

51. What is a web mapping server?
    a) A server that provides geospatial data and services to web mapping applications
    b) A server that provides access to satellite imagery
    c) A server that provides access to basemaps
    d) A server that provides access to geocoding services
    Answer: a

52. What is a geospatial web portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for sharing photos with friends and family
    c) A website for streaming movies and TV shows
    d) A website for online shopping
    Answer: a

53. What is a web mapping framework?
    a) A software framework that provides tools for building web mapping applications
    b) A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for analyzing geospatial data
    Answer: a

54. What is a geospatial web viewer?
    a) An application that allows users to view and interact with geospatial data through the internet
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

55. What is a geospatial web service interface?
    a) An interface that allows applications to access and use geospatial web services
    b) An interface that allows applications to convert addresses into geographic coordinates
    c) An interface that allows applications to convert geospatial data into a different format
    d) An interface that allows applications to measure distances between geographic features
    Answer: a

56. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

57. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social media platforms
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

58. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

59. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

60. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

61. Which of the following is an example of a web mapping library?
    a) Leaflet
    b) Photoshop
    c) Excel
    d) Spotify
    Answer: a

62. What is a web GIS application programming interface (API)?
    a) A set of programming instructions that allows developers to interact with web GIS services and data
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

63. What is a geocoding service in web GIS?
    a) A service that converts addresses into geographic coordinates
    b) A service that converts geographic coordinates into addresses
    c) A service that provides access to basemaps
    d) A service that provides access to geospatial data
    Answer: a

64. What is a web mapping server?
    a) A server that provides geospatial data and services to web mapping applications
    b) A server that provides access to satellite imagery
    c) A server that provides access to basemaps
    d) A server that provides access to geocoding services
    Answer: a

65. What is a geospatial web portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for sharing photos with friends and family
    c) A website for streaming movies and TV shows
    d) A website for online shopping
    Answer: a

66. What is a web mapping framework?
    a) A software framework that provides tools for building web mapping applications
    b) A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for analyzing geospatial data
    Answer: a

67. What is a geospatial web viewer?
    a) An application that allows users to view and interact with geospatial data through the internet
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

68. What is a geospatial web service interface?
    a) An interface that allows applications to access and use geospatial web services
    b) An interface that allows applications to convert addresses into geographic coordinates
    c) An interface that allows applications to convert geospatial data into a different format
    d) An interface that allows applications to measure distances between geographic features
    Answer: a

69. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

70. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social

 media platforms
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

71. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

72. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

73. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

74. Which of the following is an example of a web mapping library?
    a) Leaflet
    b) Photoshop
    c) Excel
    d) Spotify
    Answer: a

75. What is a web GIS application programming interface (API)?
    a) A set of programming instructions that allows developers to interact with web GIS services and data
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

76. What is a geocoding service in web GIS?
    a) A service that converts addresses into geographic coordinates
    b) A service that converts geographic coordinates into addresses
    c) A service that provides access to basemaps
    d) A service that provides access to geospatial data
    Answer: a

77. What is a web mapping server?
    a) A server that provides geospatial data and services to web mapping applications
    b) A server that provides access to satellite imagery
    c) A server that provides access to basemaps
    d) A server that provides access to geocoding services
    Answer: a

78. What is a geospatial web portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for sharing photos with friends and family
    c) A website for streaming movies and TV shows
    d) A website for online shopping
    Answer: a

79. What is a web mapping framework?
    a) A software framework that provides tools for building web mapping applications
    b) A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for analyzing geospatial data
    Answer: a

80. What is a geospatial web viewer?
    a) An application that allows users to view and interact with geospatial data through the internet
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

81. What is a geospatial web service interface?
    a) An interface that allows applications to access and use geospatial web services
    b) An interface that allows applications to convert addresses into geographic coordinates
    c) An interface that allows applications to convert geospatial data into a different format
    d) An interface that allows applications to measure distances between geographic features
    Answer: a

82. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

83. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social media platforms
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

84. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

85. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

86. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

87. Which of the following is an example of a web mapping library?
    a) Leaflet
    b) Photoshop
    c) Excel
    d) Spotify
    Answer: a

88. What is a web GIS application programming interface (API)?
    a) A set of programming instructions that allows developers to interact with web GIS services and data
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

89. What is a geocoding service in web GIS?
    a) A service that converts addresses into geographic coordinates
    b) A service that converts geographic coordinates into addresses
    c) A service that provides access to basemaps
    d) A service that provides access to geospatial data
    Answer: a

90. What is a web mapping server?
    a) A server that provides geospatial data and services to web mapping applications
    b) A server that provides access to satellite imagery
    c) A server that provides access to basemaps
    d) A server that provides access to geocoding services
    Answer: a

91. What is a geospatial web portal?
    a) A website that provides access to a collection of geospatial data and services
    b) A website for sharing photos with friends and family
    c) A website for streaming movies and TV shows
    d) A website for online shopping
    Answer: a

92. What is a web mapping framework?
    a) A software framework that provides tools for building web mapping applications
    b)

 A tool for converting geographic coordinates into addresses
    c) A tool for converting geospatial data into a different format
    d) A tool for analyzing geospatial data
    Answer: a

93. What is a geospatial web viewer?
    a) An application that allows users to view and interact with geospatial data through the internet
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for measuring distances between geographic features
    Answer: a

94. What is a geospatial web service interface?
    a) An interface that allows applications to access and use geospatial web services
    b) An interface that allows applications to convert addresses into geographic coordinates
    c) An interface that allows applications to convert geospatial data into a different format
    d) An interface that allows applications to measure distances between geographic features
    Answer: a

95. What is a web mapping framework?
    a) A software library that provides tools for building web mapping applications
    b) A tool for converting geospatial data into a different format
    c) A tool for publishing geospatial data on the web
    d) A tool for analyzing geospatial data
    Answer: a

96. What is a geospatial web service?
    a) A service that provides access to geospatial data or functionality through the internet
    b) A service that provides access to social media platforms
    c) A service that provides access to basemaps
    d) A service that provides access to satellite imagery
    Answer: a

97. What is a web GIS viewer?
    a) An application that allows users to view and interact with web maps
    b) A tool for creating 3D visualizations of geographic data
    c) A tool for converting raster data into vector data
    d) A tool for analyzing geospatial data
    Answer: a

98. What is a geospatial database in web GIS?
    a) A database that stores geospatial data and allows for spatial queries and analysis
    b) A database that stores non-spatial data in a tabular format
    c) A database that stores images and videos
    d) A database that stores social media posts
    Answer: a

99. What is a spatial analysis in web GIS?
    a) The process of examining geographic patterns and relationships within geospatial data
    b) The process of converting addresses into geographic coordinates
    c) The process of visualizing geographic data on a map
    d) The process of sharing geographic data through the internet
    Answer: a

100. Which of the following is an example of a web mapping library?
     a) Leaflet
     b) Photoshop
     c) Excel
     d) Spotify
     Answer: a



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In photogrammetry, aerial photographs are categorized based on camera orientation , coverage , and spectral sensitivity . Below is a breakdown of the major types: 1️⃣ Based on Camera Axis Orientation Type Description Key Feature Vertical Photo Taken with the camera axis pointing directly downward (within 3° of vertical). Used for maps and measurements Oblique Photo Taken with the camera axis tilted away from vertical. Covers more area but with distortions Low Oblique: Horizon not visible High Oblique: Horizon visible 2️⃣ Based on Number of Photos Taken Type Description Single Photo One image taken of an area Stereoscopic Pair Two overlapping photos for 3D viewing and depth analysis Strip or Mosaic Series of overlapping photos covering a long area, useful in mapping large regions 3️⃣ Based on Spectral Sensitivity Type Description Application Panchromatic Captures images in black and white General mapping Infrared (IR) Sensitive to infrared radiation Veget...
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Photogrammetry – Geometry of a Vertical Photograph

Photogrammetry is the science of making measurements from photographs, especially for mapping and surveying. When the camera axis is perpendicular (vertical) to the ground, the photo is called a vertical photograph , and its geometry is central to accurate mapping.  Elements of Vertical Photo Geometry In a vertical aerial photograph , the geometry is governed by the central projection principle. Here's how it works: 1. Principal Point (P) The point on the photo where the optical axis of the camera intersects the photo plane. It's the geometric center of the photo. 2. Nadir Point (N) The point on the ground directly below the camera at the time of exposure. Ideally, in a perfect vertical photo, the nadir and principal point coincide. 3. Photo Center (C) Usually coincides with the principal point in a vertical photo. 4. Ground Coordinates (X, Y, Z) Real-world (map) coordinates of objects photographed. 5. Flying Height (H) He...
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Raster Data Structure

Raster Data Raster data is like a digital photo made up of small squares called cells or pixels . Each cell shows something about that spot — like how high it is (elevation), how hot it is (temperature), or what kind of land it is (forest, water, etc.). Think of it like a graph paper where each box is colored to show what's there. Key Points What's in the cell? Each cell stores information — for example, "water" or "forest." Where is the cell? The cell's location comes from its place in the grid (like row 3, column 5). We don't need to store its exact coordinates. How Do We Decide a Cell's Value? Sometimes, one cell covers more than one thing (like part forest and part water). To choose one value , we can: Center Point: Use whatever feature is in the middle. Most Area: Use the feature that takes up the most space in the cell. Most Important: Use the most important feature (like a road or well), even if it...
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Photogrammetry

Photogrammetry is the science of taking measurements from photographs —especially to create maps, models, or 3D images of objects, land, or buildings. Imagine you take two pictures of a mountain from slightly different angles. Photogrammetry uses those photos to figure out the shape, size, and position of the mountain—just like our eyes do when we see in 3D! Concepts and Terminologies 1. Photograph A picture captured by a camera , either from the ground (terrestrial) or from above (aerial or drone). 2. Stereo Pair Two overlapping photos taken from different angles. When seen together, they help create a 3D effect —just like how two human eyes work. 3. Overlap To get a 3D model, photos must overlap each other: Forward overlap : Between two photos in a flight line (usually 60–70%) Side overlap : Between adjacent flight lines (usually 30–40%) 4. Scale The ratio of the photo size to real-world size. Example: A 1:10,000 scale photo means 1 cm on the photo...
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Logical Data Model in GIS

In GIS, a logical data model defines how data is structured and interrelated—independent of how it is physically stored or implemented. It serves as a blueprint for designing databases, focusing on the organization of entities, their attributes, and relationships, without tying them to a specific database technology. Key Features Abstraction : The logical model operates at an abstract level, emphasizing the conceptual structure of data rather than the technical details of storage or implementation. Entity-Attribute Relationships : It identifies key entities (objects or concepts) and their attributes (properties), as well as the logical relationships between them. Business Rules : Business logic is embedded in the model to enforce rules, constraints, and conditions that ensure data consistency and accuracy. Technology Independence : The logical model is platform-agnostic—it is not tied to any specific database system or storage format. Visual Representat...
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