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.