Reclassification

Overview Reclassification is a raster GISGISGeographic Information Systems (GIS) enable users to analyze and visualize spatial data to uncover patterns, relation... operation that transforms cell values from one set of categories or value ranges into a new classification scheme. By mapping original values to new values through a reclassification table or function, analysts can convert continuous data into discrete categories, simplify complex datasets, standardize multiple layers to a common scale, or update outdated classification schemes.

Several approaches to reclassification serve different analytical needs. One-to-one reclassification maps each unique input value to a specific output value, useful for updating land cover codes. Range-based reclassification assigns new values based on value ranges, such as classifying elevation into low, medium, and high terrain categories. Conditional reclassification applies logical expressions to assign new values based on multiple criteria. Reclassification can also invert value scales, merge categories, or isolate specific features by assigning all other values to NoData.

Reclassification is integral to multi-criteria suitability modeling, where different input rasters must be standardized to a common 1-to-10 scale before weighted overlayWeighted OverlayWeighted overlay is a raster analysis technique that combines multiple reclassified layers by assigning each a relati.... Land cover classificationLand Cover ClassificationLand cover classification is the process of categorizing Earth's surface into distinct classes such as forest, cropla... outputs from remote sensingRemote SensingRemote sensing is the science of collecting data about Earth's surface without direct physical contact, primarily usi... are often reclassified to match specific classification schemes required by different agencies or reporting standards. Slope reclassification supports construction suitability analysisSuitability AnalysisSuitability analysis evaluates geographic locations against multiple criteria to determine how well each area meets t... by categorizing terrain into buildable and non-buildable grades. Flood risk assessment reclassifies elevation data relative to flood stage heights to identify inundation zones.

Document reclassification rules thoroughly to ensure reproducibility. Verify that input data values match expected ranges before applying reclassification tables. Consider the impact of NoData handling on analysis results. When reclassifying continuous data into discrete classes, choose break points that are meaningful for the application rather than arbitrary equal intervals.