History of GIS

1. 1832 - Early Spatial Analysis in Epidemiology:

- Charles Picquet creates a map in Paris detailing cholera deaths per 1,000 inhabitants.

- Utilizes halftone color gradients for visual representation.

2. 1854 - John Snow's Cholera Outbreak Analysis:

- Epidemiologist John Snow identifies cholera outbreak source in London using spatial analysis.

- Maps casualties' residences and nearby water sources to pinpoint the outbreak's origin.

3. Early 20th Century - Photozincography and Layered Mapping:

- Photozincography development allows maps to be split into layers for vegetation, water, etc.

- Introduction of layers, later a key feature in GIS, for separate printing plates.

4. Mid-20th Century - Computer Facilitation of Cartography:

- Waldo Tobler's 1959 publication details using computers for cartography.

- Computer hardware development, driven by nuclear weapon research, leads to broader mapping applications by early 1960s.

5. 1960 - Canada Geographic Information System (CGIS):

- Roger Tomlinson develops the world's first operational GIS in Ottawa, Canada.

- CGIS used for Canada Land Inventory, incorporating data on soils, agriculture, wildlife, etc.

6. 1964 - Laboratory for Computer Graphics and Spatial Analysis:

- Howard T. Fisher establishes the Laboratory for Computer Graphics and Spatial Analysis at Harvard.

- Develops influential software code and systems distributed worldwide.

7. Late 1970s to Early 1980s - Commercialization of GIS:

- Public domain GIS systems MOSS and GRASS GIS in development.

- Commercial vendors (M&S Computing, ESRI, Intergraph, Bentley Systems, CARIS, ERDAS) emerge with features from CGIS.

8. 1986 - Desktop GIS Emerges:

- Mapping Display and Analysis System (MIDAS), the first desktop GIS, is released.

- Renamed MapInfo for Windows in 1990, marking the shift from research to business.

9. Late 20th Century - Consolidation and Standardization:

- Rapid growth in GIS systems consolidates on a few platforms by the end of the century.

- Users begin exploring GIS data over the Internet, requiring format and transfer standards.

10. 21st Century - Integration with IT and Internet Infrastructure:

- Integration of GIS with IT and Internet technologies like relational databases, cloud computing, SAAS, and mobile computing becomes a major trend.

- Growing number of free, open-source GIS packages customized for specific tasks.

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Photogrammetry – Types of Photographs

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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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