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Dear all,
I am trying to create a vector file of a 25Mb raster landuse image so that I
may link landuse to a database. The image contains 30 different landuse
types. I am using Idrisi32 with the latest update on a Windows 98 machine.
The area of interest (a watershed) is surrounded by pixels with a value of
zero - ie the backround.
POLYVEC successfully converts the image to a vector layer, however two
contiguous (different values) landuse areas in the raster image are not
converted into polygons. All other contiguous areas that share the same
value are displayed correctly. The area of the 'unformed' polygons in the
new vector layer is identified correctly when clicked on within Idrisi32 but
the area does not highlight. One of these areas appears to be 'open' to the
backround value (ie there is no line separating the background and the
landuse, even though the boundary is clearly defined in the raster image.
Although the areas are contiguos, their natural shape is very contorted (one
layer has 26 'islands') and sometimes only one pixel wide (one layer is a
road). Could thin diagonals and/or and the contorted shape of some landuse
areas be causing this problem? How can I fix it? The vector image takes a
very long time to load in CartaLinx (a program that I am unfamiliar with)
and when it does load boundaries appear correctly formed.
Thanks in advance for any suggestions.
Les McNamara
University of Western Sydney
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