SpatialTools

cpc.sau.lulctools
Class SpatialTools

java.lang.Object
  cpc.sau.lulctools.SpatialTools

public class SpatialTools
extends java.lang.Object

This class contains various tools that can operate on individual cells, parcels or the landscape. For cells, there are methods that create LulcCell objects using raster files, identify edges of cells across the landscape, locate individual cells given a coordinate position, and indentify neighbors of individual cells.

For parcels, there are tools that create Parcel objects from either the LULC type or the parcel ID, locate a parcel using its parcel ID, and calculate the Euclidean Nearest-neighbor distance between two parcels of the same LULC type.

Other methods include the ability to split parcels or properties up to a user-specified maximum size and a method to determine the number of parcels on a property.

These methods can be called using the syntax: SpatialTools.theMethodName(parameter list).

SpatialTools

public SpatialTools()

createRasterSpace

public static java.util.ArrayList createRasterSpace(java.lang.String propertyFile,
                                                    java.lang.String lulcFile,
                                                    java.lang.String parcelFile)

Creates a new RasterSpace object that represents the modeling landscape through three approaches: property IDs, LULC values, or parcel IDs.

Parameters:

propertyFile - an ESRI ASCII Raster file containing property IDs for all cells

lulcFile - an ESRI ASCII Raster file containing LULC values for all cells

parcelFile - an ESRI ASCII Raster file containing parcel IDs for all cells

Returns:

List containing LulcCell objects on the landscape

setCellEdge

public static void setCellEdge(java.util.ArrayList<LulcCell> coverList)

This method calculates the cell edges across the landscape and initializes the edges and isEdgeCell attributes of all cells. For each LulcCell object, it identifies its 4-neighbor cells. If there is a neighboring cell with a different parcel ID, the edges attribute of the cell increases by one.

Parameters:

coverList - the list containing all LulcCell objects on the landscape

edge

public static int edge(LulcCell lc,
                       LulcCell lc2)

Checks whether there is an edge between two adjacent cells. If the parcel IDs of these two cells are different, an edge exists.

Parameters:

lc - an LulcCell object

lc2 - an LulcCell object

Returns:

A 0 if no edge exists, and 1 if an edge does exist.

getCellAt

public static LulcCell getCellAt(java.util.ArrayList coverList,
                                 int x,
                                 int y)

Returns an LulcCell object at the position(x,y).

Parameters:

coverList - the list containing all LulcCell objects on the landscape

x - the x coordinate of the LulcCell object

y - the y coordinate of the LulcCell object

Returns:

the LulcCell at the position(x,y)

getNeighborLulc

public static java.util.ArrayList<LulcCell> getNeighborLulc(LulcCell lc,
                                                            java.util.ArrayList<LulcCell> coverList)

Returns neighboring land use around an LulcCell object, using the 4-neighbor relationship. The order of the neighborhood list is west, north, east, south.

Parameters:

lc - LulcCell object

coverList - list containing all LulcCell objects on the landscape

Returns:

a list containing all neighborhood LulcCell objects around a cell

parcelListByID

public static java.util.ArrayList<Parcel> parcelListByID(java.util.ArrayList<LulcCell> coverList)

Converts a list of LulcCell objects to a list of Parcel objects using the parcel IDs. This method uses the unique parcel ID of cells to classify the parcels.

Parameters:

coverList - the list containing all LulcCell objects on the landscape

Returns:

list containing all parcels on the landscape

parceListByType

public static java.util.ArrayList<Parcel> parceListByType(java.util.ArrayList<Parcel> pList)

Converts a list of LulcCell objects to a list of Parcel objects using the LULC type. All contiguous cells on the landscape with the same land use type are grouped into parcels and the cells in each parcel are given the ID of the parcel.

Parameters:

pList - the list containing all parcels based on their unique parcel IDs. This list can created with the parceListByID method.

Returns:

list containing parcels based on land use type

getParcel

public static Parcel getParcel(java.util.ArrayList<Parcel> pList,
                               java.lang.String pid)

Locate a parcel by its parcel ID.

Parameters:

pList - the list containing all parcels on the landscape

pid - the parcel id

Returns:

a parcel with parcel ID as the parameter

getEnn

public static double getEnn(Parcel parcel,
                            java.util.ArrayList<LulcCell> coverList)

Return the Euclidean Nearest-Neighbor distance(ENN). It equals the distance, in meters, to the nearest neighboring patch of the same type(class), based on shortest edge-to-edge distance when computed from cell center to cell center. ENN is undefined and reported as -1 if the patch has no neighbors(i.e. no other patches of the same class). ENN approaches 0 as the distance to the nearest neighbor decreases. The minimum ENN is constrained by the cell size. Here we use the 4-neighbor rule, so the minimum ENN is the distance between diagonal neighbors.

Parameters:

parcel - the parcel of interest

coverList - the LulcCell list for the landscape

Returns:

the distance from the parcel to the nearest neighboring patch of the same LULC type(class).

shortDist

public static double shortDist(Parcel p,
                               Parcel p2)

Calculates the shortest distance between two parcels. It is based on edge-to-edge distance. The calculation is between edge cells. It calculates the distance from every edge cell in one parcel to every edge cell in a second parcel and returns the shortest distance.

NOTE: This alorithm may not operate very efficiently on large landscapes. A more efficient version will be made available in the future.

Parameters:

p - parcel of interest

p2 - second parcel with the same LULC as parcel p

Returns:

the shortest distance between the two parcels.

getNumParcelsOnProperty

public static int getNumParcelsOnProperty(java.util.ArrayList<Parcel> pList,
                                          java.lang.String propertyid)

Returns the largest parcel id on a property with the given property ID. The parcel ID on a farm is a sequence integer. This method identifies the largest parcel ID on the property. It is useful for creating a new parcel ID for a newly divided parcel.

Parameters:

pList - the list containing all parcels on the landscape

propertyid - the property ID

Returns:

the maximum parcel ID on a property

splitByScore

public static java.util.Set<LulcCell> splitByScore(java.util.ArrayList<LulcCell> covers,
                                                   int max)

Splits a property or parcel based on the suitability scores of its cells. It chooses a cell with best score as the seed cell and begins a growth algorithm. From the seed cell, it searches its neighboring cells and finds the cell with best suitability score.

This cell is added to the first. It then searches all cells neighboring the two selected cells and chooses the one with the best score and selects it. This process continues until the maximum number of cells desired is reached. These cells are then taken from the original parcel and converted to a new parcel

Parameters:

covers - list containing all LulcCell objects on the landscape

max - the maximum size of the subdivision

Returns:

a new list containing the subdivided cells