vLATE 1.0
[Vector-based Landscape Analysis Tools
Extension for ArcGIS - 1.0]
General information
- You'll have to use a polygon shapefile (*.shp). GRID and Geodatabase files
are not supported. The vLATE 1.0 command is grayed out
until you will load a shapefile into ArcMAP.
- If you have problems
exporting
class level data to a *.txt file and re-importing it into ArcMAP
it is recommended to switch to English regional settings. Make sure that the decimal
delimiter is a dot and not a comma.
- On-the-fly projections are not supported yet, only the original data will be
used for calculations. It is therefore strongly recommended to use projected
files, e.g. using the UTM system. You should use meters for map and
display units.
- For larger polygon shapefiles (~ more than 1500 polygons)
processing
time will increase significantly. This is mainly caused by the lack of
topological information in the *.shp format. So any calculations that
require multiple loops (Nearest Neighbour,
Proximity and Dissolve-ID) may take some time. Note that in fact the program works very stable and even
if it seems to cease do not interrupt. You may let the computer work overnight.
- If there is no class
field available
(e.g. your shapefile has only one class) the extension will automatically
create one.
- Where calculation is not
applicable field values in the shapefile will set to -999.
- For more information about the implemented landscape metrics consult the
IDEFIX database.

Description of functions
- Calculates Area and Perimeter for the selected polygon shapefile.
The tree structure of calculations [1], [4]-[9] provides a
guideline for a logical order of analysis. If you, for example, want to
perform the Edge Analysis you'll have to calculate Area/Perimeter first. To use the buttons of the different categories of analysis
[4]-[9] you need to calculate Area/Perimeter
only
once.
- Proximity Analysis:
Nearest Neighbour calculation for selected classes. This will add
three fields to the table: Distance to Nearest Neighbour (NNDist),
the ID of the NN polygon (NNID) and the Area of the NN (NN_Area).
Proximity (fragstats):
Calculates the proximity as implemented in Fragstats
(McGarigal & Marks, 1995). There will be a respective field added
to the shapefile table (PXfg_PB
- where PB stands for the chosen Proximity Buffer size)
- Information field:
Shows the currently chosen class field and selected classes.
Use the change
buttons to change the class field or the classes for the calculations.
- Area Analysis: Calculates Number of patches (NP), Class Area
in m² (CA), Mean Patch Size in m² (MPS), Patch Size
Standard-Deviation in m² (PSSD) for selected classes. Results
can be saved as text file (*.txt).
- Edge Analysis: Calculates Mean Patch Edge in m (MPE), Total
Edge in m (TE) and Edge Density in m/ha (ED) for selected classes.
Results can be saved as text file (*.txt).
- Form Analysis: Calculates Mean Shape
Index (MSI), Mean Perimeter-Area ratio (MPAR), Mean Fractal
Dimension (MFRACT) on class level and Fractal Dimension (FD),
Perimeter-Area Ratio (PARATIO), Shape Index (SHAPE) on patch
level for selected classes. Results can be saved as textfile (*.txt). The
results on patch level will added in three different fields to the attribute
table (Paratio, Shape_Idx and Frac_Dim). If the Patch
Area is equal or smaller than 1 map units, the Frac_Dim value will
be set to -9999 ("No Data").
- Core Area Analysis: Creates a new theme/layer representing the interior
of a patch (core area) based on a user-specified buffer distance and produces
a table. Calculates Total Area in m² (TA), Total Core Area in
m² (TCA), Core Area Index in % (CAI), Number of Core Areas
(NCA), Total Class Core Area in m² (TCCA) and CORITY
(equals the # of patches minus # of patches without core area divided by #
of resulting core area (including size = 0!)).
NB: The resulting core area may differ from core area calculation in ArcView
3.x due to differing algorithms. It seems that buffering in ArcGIS is now
more accurate.
- Diversity Analysis: Calculates Richness, Shannon´s
Diversity Index, Shannon´s Evenness Index, Dominance
and Proportion of class for selected classes. Results can be saved
as text file (*.txt).
- Subdivision Analysis: Calculates Landscape Division Index (DIVISION),
Splitting Index (SPLIT) and Effective Mesh Size (MESH). Results
can be saved as text file (*.txt).
- Dissolve ID: Creates a Dissolve ID for every adjacent polygon of
the same class. Based on this Dissolve_ID field one can use the GeoprocessingWizard
of ArcMAP to dissolve the adjacent polygons of the same class (without this
Dissolve_ID the GeoprocessingWizard will create multipart shapefiles for every
class, which are not suitable for implemented calculations).
- Delete Fields: Delete one or several fields in the attribute table.
- IDEFIX Database: Launches the IDEFIX (Indicator Database for Scientific
Exchange) database, if available under the specified path.
- Help: Opens this help file (if stored in the same folder as the V_LATE_1.dll)
Overview categories and
abbreviations:
