Spatial Analysis
Query in GIS The fundamental purpose of any GIS is to retrieval of desired information. This is achieved through a process known as query. Query are of two types - spatial and attribute . Spatial Query A s patial Query is a fundamental analytical operation used to retrieve spatial features based on their topological relationships , g eometric properties or thematic properties within a defined geographic space. Example for topological query - The Scenario: Urban Planning Imagine you are working with a city's GIS database containing three layers: Parcels (Polygons representing land ownership) Zoning Districts (Polygons for Residential, Industrial, etc.) Utility Lines (Lines representing water pipes) 1. Adjacency (What is next to what?) The Query: "Find all residential parcels that share a boundary with an industrial zone." 2. Containment (What is inside what?) The Query: "Select all water valves located wi...