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“What is a port?” · “Why is my code erroring?”
Two geometries relate in one of a fixed set of ways, and a spatial predicate is the true or false test that names which one, with intersects doing most of the real work.
How Geometries Relate: Topology and Predicates
Two geometries relate in one of a fixed set of ways, and a spatial predicate is the true or false test that names which one, with intersects doing most of the real work.
Buffers and Proximity: What Is Near What
A buffer draws a zone at a fixed distance around a feature, and getting that distance right depends on projecting to a metric CRS before drawing it.
Overlay: Clip, Intersect, Union, and Difference
Overlay combines two polygon layers into a genuinely new one, and clip, intersect, union, and difference are four distinct ways to do that combining, each answering a different question.
Spatial Joins: Combining Data by Location
A spatial join attaches one layer's attributes to another based on where two geometries sit, not on a shared key, using a predicate like within or nearest and often needing a groupby afterward to summarize a one-to-many match.
Raster Analysis: Map Algebra and Terrain
Map algebra runs the same arithmetic on every cell of a raster at once, which is how a grid of elevation turns into slope, slope turns into suitability classes, and several criteria collapse into a single answer.
Density, Interpolation, and Zonal Statistics
Turning scattered points into a smooth surface, filling gaps between measurements, and summarizing a raster inside each polygon are the three moves that make raw spatial data usable.