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Patch analysis是一款不错的景观生态学分析软件,的最大特点在于能够借助于ARCGIS平台对矢量图层(shipfile)和栅格图层(GRID)进行分析,指数虽然没有软件丰富,但也能常规需求。该软件作为Arcview 3.X的扩展模块由Avenue语言编写,需要空间分析模块(Spatial Analyst)支持,能够对shape或Grid进行常用的景观指数计算。软件开发者开发了能够搭载ARCGIS9.X和ARCGIS10版本的适用程序,计算结果也可以直接转入Excel或其它关系数据库软件或统计中分析。
软件下载地址为:http://www.cnfer.on.ca/SEP/patchanalyst/。
Metric Definitions (from McGarigal and Marks, 1994 and McGarigal and Marks, 1995)
Class Area (CA)
Sum of areas of all patches belonging to a given class.
Example: Conifer Class Area (CA) = 359047.844+......+65819.984
CA = 69.6626 hectares
If the map units are not specified (i.e., Data Frame properties; see Set map units) and "State areas in Hectares" has not been selected in the "Advanced Options" of the "Spatial Statistics" dialog box, then the resulting statistics will be reported in native map units (vector layers (themes) only).
In the example; CA = 696626.012 (map units). This is the case for most statistics.
Landscape Area (TLA)
Sum of areas of all patches in the landscape.
Example: Landscape Area (TLA) = 46872.719 + 359047.844 +... + 62423.574 TLA = 184.11 hectares
Percentage of Landscape (ZLAND)
When analyzing by class, ZLAND is the percentage of the total landscape made up of the corresponding class (patch type).
Number of Patches (NumP)
Total number of patches in the landscape if "Analyze by Landscape" is selected, or Number of Patches for each individual class, if "Analyze by Class" is selected.
Example: Class Level: Number of Patches (NumP)
Mixedwood = 5, Conifer = 4, Deciduous = 5
Landscape Level: Number of Patches (NumP) = 14
Patch Richness (PR)
PR is the number of different patch types within the landcape's boundary.
Patch Richness Density (PRD)
PRD is equal to PR divided by the total area of the landscape (metres squared) multiplied by 10,000 and then 100 (to convert to hundreds of hectares).
Largest Patch Index (LPI)
The LPI is equal to the percent of the total landscape that is made up by the largest patch.
When the entire landscape is made up of a single patch, the LPI will equal 100. As the size of the largest patch decreases, the LPI approaches 0.
Mean Patch Size (MPS)
Average patch size.
Example: Mean Patch Size of Conifer Patches (Class Level)
MPS = (359047.844 + 139531.484 ...+ 65819.984)/4
MPS = 17.42 hectares
Example: Mean Patch Size of Patches (Landscape Level)
MPS = (46872.719 + 359047.844 + ... + 62432.574)/14
MPS = 13.15 hectares
Median Patch Size (MedPS)
The middle patch size, or 50th percentile.
Example: Median Patch size of Conifer Patches (Class Level)
MedPS = 13.22 hectares
Example: Median Patch size of all patches (Landscape Level)
MedPS = 7.59 hectares
Patch Size Standard Deviation (PSSD)
Standard Deviation of patch areas.
Example: Patch Size Standard Deviation of Conifer Patches (Class Level)
PSSD = 11.05 hectares
Example: Patch Size Standard Deviation of all patches (Landscape Level)
PSSD = 9.51 hectares
Patch Size Coefficient of Variance (PSCoV)
Coefficient of variation of patches.
Example: Coefficient of Variation of Conifer patches (Class Level)
PSCoV = PSSD/MPS = (11.05 hectares / 17.42 hectares) *100 = 63
Example: Coefficient of Variation of all patches (Landscape Level)
PSCoV = (9.51 hectares / 13.15 hectares)*100 =72
Total Edge (TE)
Perimeter of patches.
Example: Total Edge Conifer (Class Level)
TE = Sum of perimeter of all conifer patches.
TE = 10858.88 metres
Units are expressed in native maps units.
Example: Total Edge all patches (Landscape Level)
TE = Sum of perimeter of all patches
TE = 28607.27 metres
Important
In the case of vector layers (themes), edge calculations include all the edge on the landscape including boundary edge. The contrasted weighted edge feature allows edge weight at the boundaries to be set to zero. In the case of raster (grid) layers (themes), edge calculations do not include the edges that surround the landscape boundary edge or any interior edges that include pixels classified as No Data.
Edge Density (ED)
Amount of edge relative to the landscape area.
Example: Edge Density Conifer (Class Level)
ED = TE / TLA
ED = 10858.88 metres/184.11 hectares = 58.98 metres/hectare
Example: Edge Density of all Patches (Landscape Level)
ED = 28607.27 metres/184.11 hectares = 155.38 metres/hectare
Mean Patch Edge (MPE)
Average amount of edge per patch.
Example: Mean Patch Edge Conifer (Class Level)
MPE = TE / NumP
MPE = 10858.88 metres/4 patches = 2714.72 metres/patch
Example: Mean Patch Edge all Patches (Landscape Level)
MPE = TE / NumP
MPE = 28607.27 metres/14 patches = 2043.38 metres/patch
Contrasted Weighted Edge Density (CWED)
CWED is a measure of density of edge in a landscape (metres per hectare) with a user-specified contrast weight.
CWED is equal to 0 when there is no edge in the landscape, in other words the whole landscape and it's border are made up of a single patch. It's value increases as the amount of edge in the landscape increases and/or as the user increases the contrast weight.
Landscape Shape Index (LSI)
LSI is the total landscape boundary and all edge within the boundary divided by the square root of the total landscape area (square metres) and adjusted by a constant (circular standard for vector layers, square standard for rasters). The LSI will increase with increasing landscape shape irregularity or increasing amounts of edge within the landscape.
Double Log Fractal Dimension (DLFD)
DLFD is a measure of patch perimeter complexity. It nears 1 when patch shapes are 'simple', such as circles or squares and it approaches 2 as patch shape perimeter complexity increases.
Mean Perimeter-Area Ratio (MPAR)
Shape Complexity.
Example: Mean perimeter-area ratio Conifer (Class Level)
MPAR = Sum of each patches perimeter/area ratio divided by number of patches.
MPAR = (132 m/ha + 112 m/ha + 201 m/ha + 84 m/ha)/4 patches
MPAR = 182 metres/hectare
Example: Mean perimeter-area ratio all patches (Landscape Level)
MPAR = (200 m/ha + 132 m/ha + ... + 175 m/ha)/14 patches
MPAR = 185 metres/hectare
Mean Shape Index (MSI)
Shape Complexity.
MSI is equal to 1 when all patches are circular (for polygons) or square (for rasters (grids)) and it increases with increasing patch shape irregularity.
MSI = sum of each patch's perimeter divided by the square root of patch area (in hectares) for each class (when analyzing by class) or all patches (when analyzing by landscape), and adjusted for circular standard ( for polygons), or square standard (for rasters (grids)), divided by the number of patches.
Area Weighted Mean Shape Index (AWMSI)
AWMSI is equal to 1 when all patches are circular (for polygons) or square (for rasters (grids)) and it increases with increasing patch shape irregularity.
AWMSI equals the sum of each patch's perimeter, divided by the square root of patch area (in hectares) for each class (when analyzing by class) or for all patches (when analyzing by landscape), and adjusted for circular standard ( for polygons), or square standard (for rasters (grids)), divided by the number of patches. It differs from the MSI in that it's weighted by patch area so larger patches will weigh more than smaller ones.
Mean Patch Fractal Dimension (MPFD)
Shape Complexity.
Mean patch fractal dimension (MPFD) is another measure of shape complexity. Mean fractal dimension approaches one for shapes with simple perimeters and approaches two when shapes are more complex.
Area Weighted Mean Patch Fractal Dimension (AWMPFD)
Shape Complexity adjusted for shape size.
Area weighted mean patch fractal dimension is the same as mean patch fractal dimension with the addition of individual patch area weighting applied to each patch. Because larger patches tend to be more complex than smaller patches, this has the effect of determining patch complexity independent of its size. The unit of measure is the same as mean patch fractal dimension.
Mean Nearest Neighbor (MNN)
Measure of patch isolation.
The nearest neighbor distance of an individual patch is the shortest distance to a similar patch (edge to edge). The mean nearest neighbor distance is the average of these distances (metres) for individual classes at the class level and the mean of the class nearest neighbor distances at the landscape level.
Interspersion Juxtaposition Index (IJI)
Measure of patch adacency.
Approaches zero when the distribution of unique patch adjacencies becomes uneven and 100 when all patch types are equally adjacent.
Interspersion requires that the landscape be made up of a minimum of three classes. At the class level interspersion is a measure of relative interspersion of each class. At the landscape level it is a measure of the interspersion of the each patch in the landscape.
Mean Proximity Index (MPI)
Measure of the degree of isolation and fragmentation.
Mean proximity index is a measure of the degree of isolation and fragmentation of a patch. MPI uses the nearest neighbor statistic. The distance threshold default is 1,000,000. If MPI is required at specific distances, select Set MPI Threshold from the main Patch pull-down menu and enter a threshold distance.
Both MNN and MPI use the nearest neighbor statistic of similar polygons in their algorithm. Occasionally a blank or zero will be reported in MNN and MPI fields. This happens when one polygon vertex touches another polygons border but the two similar polygons do not share a common border. When this happens a manual edit (move) of the touching vertex will correct the problem in the layer (theme). This problem will not happen when analyzing raster (grid) layers (themes).
Shannon's Diversity Index (SDI)
Measure of relative patch diversity.
Shannon's diversity index is only available at the landscape level and is a relative measure of patch diversity. The index will equal zero when there is only one patch in the landscape and increases as the number of patch types or proportional distribution of patch types increases.
Simpson's Diversity Index (SIDI)
Measure of relative patch diversity.
Simpson's diversity index is only available at the landscape level and is a relative measure of patch diversity. The index will equal zero when there is only one patch in the landscape and increases as the number of patch types or proportional distribution of patch types increases.
Shannon's Evenness Index (SEI)
Measure of patch distribution and abundance.
Shannon's evenness index is equal to zero when the observed patch distribution is low and approaches one when the distribution of patch types becomes more even. Shannon's evenness index is only available at the landscape level.
Simpson's Evenness Index (SIEI)
SIEI is a measure of the distribution of area among patch types. It equals 1 when the distribution of area among patches is exactly even. SIEI approaches 0 as the distribution of area among the patches become more and more dominated by one patch type.
Modified Simpson's Diversity Index (MSIDI)
MSIDI is a measure of patch diversity. It equals zero when there is only one patch in the landscape and increases as the number of different patch types (PR) increases and the area among patch types becomes more equal.
Modified Simpson's Evenness Index (MSIEI)
MSIEI is a measure of the distribution of area among patch types. It equals 1 when the distribution of area among patches is exactly even. SIEI approaches 0 as the distribution of area among the patches become more and more dominated by one patch type. It differs from SIEI in that it is derived from the Modified Simpson's Diversity Index (MSIDI) rather than the Simpson's Diversity Index (SIDI).
Important
Direct analyses of Core Area through the spatial statistics dialogue are only available for raster (grid) layers (themes). If core area statistics are required for vector layers (themes), first Create Core Areas (create a new core area theme) from the Patch pull-down menu and then calculate statistics for the new layer (theme) as you would for a normal vector layer (theme). The results will be core area statistics.
Total Core Area (CA)
The total size of disjunct core patches.
The total size of disjunct core area patches (hectares).
Mean Core Area (MCA)
The average size of disjunct core patches.
The mean size of disjunct core area patches (hectares).
Number of Core Areas (NCA)
The total number of disjunct core areas within each patch of a corresponding patch type (or class).
Mean Core Area Index (MCAI)
MCAI is the average percentage of a landscape patch that is core area. It will be equal to 0 when there is no core area present in any patch in the landscape and it increases (towards 100%) when patches contain mostly core area.
Core Area Standard Deviation (CASD)
Measure of variability in core area size.
The standard deviation of disjunct core areas (hectares).
Core Area Density (CAD)
The relative number of disjunct core patches relative to the landscape area.
The total number of all disjunct patches divided by the landscape area (number of disjunct core patches/hectare).
Total Core Area Index (TCAI)
Measure of amount of core area in the landscape.
Total core area index is a measure of the amount of core area in the landscape. Total core area index is a proportion of core area in the entire landscape and is equal to zero when no patches in the landscape contain core and approaches one as the relative proportion of core area in the landscape increases.
Core Area Percentage of Land (C_LAND)
C_LAND is the percentage of the total landscape which is made up of core area.
Mean Core Area per Patch (MCA1)
MCA1 is the average core area per patch (as opposed to all distunct core areas).
It equals the sum of the core areas of each patch or corresponding patch type, divided by the number of total patches of the same type, divided by 10, 000 (to convert to hectares).
Core Area Coefficient of Variance (CACOV)
CACOV represents the variability in size of disjunct core areas in relation to the mean core area.
Patch Core Area Standard Deviation (CASD1)
Measure of variability in patch core area size.
The standard deviation of patch core areas (hectares).
Patch Core Area Coefficient of Variation (CACV1)
The standard deviation in core areas (CASD) divided by the mean core area per patch (MCA) and multplied by 100 (%).
The variablility in core area among patches relative to the mean core area. | 度量定义(从McGarigal和标志,1995年,1994年和McGarigal和标记) |
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