Converting data

ArcGIS Spatial Analyst allows you to convert from features to a raster or from a raster to features.

Converting features to a raster
You can convert point, line, and polygon features from any type of source file to a raster using both string and numeric attribute fields. If you use a string field, ArcGIS Spatial Analyst assigns each unique string in the field a unique value in the output raster. It then adds a field to the table of the output raster to hold the original string value from the features.

When you convert points, Spatial Analyst assigns each cell the value of the point found within it. Cells that do not contain a point are assigned a NoData value. If more than one point is found in a cell, the cell is given the value of the first point it encounters.

When you convert lines, Spatial Analyst assigns each cell the value of the line that intersects it. Cells that are not intersected by a line are assigned a NoData value. If more than one line intersects a cell, the cell is assigned the value of the first line it encounters when processing.

When you convert polygons, Spatial Analyst assigns each cell the value of the polygon that contains the centroid of the cell.

Converting a raster to features
When converting a raster to point features, Spatial Analyst creates a point for each non-NoData cell. The point coordinates are those of the centroid of the cell.

When converting a raster representing linear features to polyline features, Spatial Analyst creates lines from connected chains of same-value cells so that the lines pass through the center of the cells.

When converting a raster representing areas, Spatial Analyst builds polygon features from groups of connected same-value cells. The bounding lines are created from the external cell borders.