OPERATIONS ON ZONES

OPERATIONS ON ZONES - errors may cancel out Distance from...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
OPERATIONS ON ZONES (GROUPS OF PIXELS) Identifying zones by comparing adjacent pixels, identify all patches or zones having the same value give each such patch or zone a unique number set each pixel's value to the number of its patch or zone Areas of zones measure the area of each zone and assign this value to each pixel instead of the zone's number o alternatively output may be in the form of a summary table sent to the printer or a file Perimeter of zones measure the perimeter of each zone and assign this value to each pixel instead of the zone's number o alternatively output may be in the form of a summary table sent to the printer or a file length of perimeter is determined by summing the number of exterior cell edges in each zone note: the values calculated in both area and perimeter are highly dependent upon the orientation of objects (zones) with respect to the orientation of the grid o however, if boundaries in the study area do not have a dominant orientation such
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: errors may cancel out Distance from zone boundary measure the distance from each pixel to the nearest part of its zone boundary, and assign this value to the pixel o boundary is defined as the pixels which are adjacent to pixels of different values Shape of zone measure the shape of the zone and assign this to each pixel in the zone o one of the most common ways to measure shape is by comparing the perimeter length of a zone to the square root of its area o by dividing this number by 3.54 we get a measure which ranges from 1 for a circle (the most compact shape possible) to 1.13 for a square to large numbers for long, thin, wiggly zones commands like this are important in landscape ecology o helpful in studying the effects of geometry and spatial arrangement of habitat e.g. size and shape of woodlots on the animal species they can sustain e.g. value of linear park corridors across urban areas in allowing migration of animal species...
View Full Document

Ask a homework question - tutors are online