How to calculate the the number and area of habitat patches in Arcview 10

Question

I'm currently working on my masters thesis and having real trouble with GIS. I've downloaded the arc gis grid data set from http://www.kew.org/gis/projects/mad_veg/datasets_gis.html

Ive sucessfully plotted it in arcmap 10. The map consists of various different habitats. I want to know how I could take one of those habitats types, say "humid forest", and calculate how many patches of that habitat there are, and how big each patch is.

I've been been at this for weeks and haven't made much headway. someone suggested I look at zonal geometry as a table http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z000000w5000000.htm which look promising but I gave the coding a try and I couldnt get it to work. I posted some of my attempts below.

>>> import arcpy
>>> from arcpy import env
>>> from arcpy.sa import *
>>> env.workspace = "Q:/MADGIS"
>>> outZonalGeometryAsTable = ZonalGeometryAsTable("zones.shp", "Classes      "zonalgeomout", 0.2)
Runtime error <class 'arcgisscripting.ExecuteError'>: ERROR 000626: Tool     ZonalGeometryAsTable is not licensed. 
>>> arcpy.CheckOutExtension("Spatial")
u'CheckedOut'
>>> outZonalGeometryAsTable = ZonalGeometryAsTable(inZoneData, zoneField, "AREA",       cellSize)
Runtime error <type 'exceptions.NameError'>: name 'inZoneData' is not defined

The problem is some of the things ive copied in the example are specific to the example, but i'm not sure. If someone could even point me in the right direction it would be a big help

Answer 1

It seems that you didn’t set some parameters. According to the link above, you must set this parameters:

# Set local variables
inZoneData = "YourShapefileName.shp"
zoneField = "Classes"
outTable = "zonalgeomout02.dbf"
processingCellSize = 0.2

# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")

Update:

You must use this code for your raster data:

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/Users/Puya/Downloads/Documents/StackOverflow/veg_grid"
inZoneData = "vegetation"
zoneField = "Value"
outTable = "zonalgeomout02.dbf" 
processingCellSize = 29
arcpy.CheckOutExtension("Spatial")
outZonalGeometryAsTable = ZonalGeometryAsTable(inZoneData, zoneField, "AREA", processingCellSize)

Also, in ArcMap you can use ArcToolbox -> Spatial Analyst -> Zonal -> ZonalGeometryAsTable and select above parameters and run ZonalGeometryAsTable.