public Collection<Column<V>> columns() {
		List<Column<V>> result = new ArrayList<>();
		Collection<Column<V>> values = columnsByIndex.values();
		for (Column<V> column : values) {
			result.add(column);
		}
		return result;
	}
Returns the columns in this location map, sorted from lowest index to highest 

@return the columns in this location map, sorted from lowest index to highest
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/LayoutLocationMap.java