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Study / GIS Fundamentals
GIS Fundamentals
Start here if the terms are new. Each topic is a short theory note. Where a hands-on practical exists, its icon sits beside the topic.
8 theory notes
Foundations
1 guide- 01GIS Fundamentals: A Beginner's GuideWhat GIS is, how it differs from GPS and remote sensing, how spatial data is stored, and how coordinate systems, EPSG codes, WGS84, UTM and Web Mercator fit together.
Preparing data
5 guides- 02Where Spatial Data Comes From: Open Data, Web Services and OpenStreetMapThe main sources of spatial data, how licences and credit work, how web tile and map services deliver data, and how OpenStreetMap stores features as tags.
- 03Rainfall and Weather Data Products: Gauges, Satellites and ReanalysisWhere rainfall and weather numbers come from, how a gauge, a satellite estimate, a blended product and a reanalysis differ, and how to choose one and report it honestly.
- 04Georeferencing, Digitization and TopologyHow a scanned map becomes usable GIS data: place it with control points, trace its features into points, lines and polygons, and keep the relationships between features clean with topology.
- 05Transformations in GIS: Datum, Coordinate and Image TransformationsThe four things GIS calls a transformation: reprojection, datum shifts, georeferencing fits and resampling, with the types, how many control points each needs and how to judge the error.
- 06Mosaicking, Tiling and Clipping RastersWhy satellite and elevation data come in tiles, what has to match before tiles can be joined, how overlaps and seams are handled, and how clipping, cropping and masking differ.
Storing data
2 guides- 07Spatial Databases, Spatial Indexing and PostGISWhat makes a database spatial, how a spatial index speeds up location queries, and what PostGIS adds to PostgreSQL for working with large geographic datasets.
- 08Geospatial File Formats: GeoTIFF, GeoPackage and ShapefileWhat GeoTIFF and GeoPackage are, how a shapefile compares with a GeoPackage, and how to decide between vector and raster data.