Hi Michael,
...even the time to vectorialize a raster with continuous data like DTM084 is
incredibly long...
In theory in mostly case an user chooses one of Raster->Vector tool according
to the type of the raster she/he wants to convert:
a) a continuous raster like a DTM. Data are scattered in a continuous interval
descibing a measure that gradually changes, for instance the elevation or a map
of temperatures. An user wonts to convert into a contour lines (Raster to
contours) or trasform into a discrete raster (eg. defining intervals of the
measure: 10-30% slope, 31-50% slope and so on
a) a discrete raster can be converted to a polygon layer (the case of Raster to
Polygons. See file UsoSuolo.tif by Roberto: each number with 3 digits (512,
111, etc) define a unique usage of the soil (forsets, cultivar, urban, etc).
There is neither no uniform measurement (a forest is different from a city) nor
a continuous gradually change (after 111 there would be a 231 in the scale, for
instance): we use number because we get advance (and the limit) that the Z
value of a raster accept only a number (float, double, integer or whatever, but
only a number not a string).
Of coarse, if we consider the limit of the interval and the cell size, all the
raster are tecnically discrete (each output polygon can have a size of the cell
size: see Stefan's tools, create a grid of points/of polygons).
When I added this plugin to OpenJUMP I wanted to bypass in one time two
problems:
a) Sextante Raster to Vector tool on discrete raster sometimes was giving
wierd results: island of no data where it was supposed to have valid data
b) the version of Raster to Polygon tool in OpenKLEM, derived from AdbToolbox
software, was taking a longer time and giving sometimes a strange outputs (like
sometimes self intersection polygons).
This plugin seems to solve both situations. OpenKLEM now refers to
VectorizeAlgorithm class, part AdbToolbox. While embedded OpenJUMP plugin can
use both algorithm. They both work, except if user wants to convert a
continuous raster to polygons with AdbToolbox.
I will give a look and atry to correct or to add some type of check, studing a
way to distinguish in OpenJUMP a continuous vs discrete raster, not sure if it
possible (an histogram is required and OJ raster histogram plugin can take a
very long time according the intervals.
Best regards
Peppe
---
** [bugs:#510] Create Polygon From a Raster bug**
**Status:** open
**Milestone:** OJ_1.16
**Created:** Tue Nov 10, 2020 12:59 PM UTC by michael michaud
**Last Updated:** Tue Nov 10, 2020 12:59 PM UTC
**Owner:** nobody
The plugin has two modes : AdbToolbox and Sextante. With tiff images of type
float like DTM084 from Roberto Rossi, I can vectorize with Sextante, but Adb
throws en exception :
java.lang.ArrayIndexOutOfBoundsException: Index -9999 out of bounds for length
1925123
at
org.openjump.core.rasterimage.algorithms.VectorizeAlgorithm.toPolygonsAdbToolBox(VectorizeAlgorithm.java:113)
at
org.openjump.core.ui.plugin.raster.VectorizeToPolygonsPlugIn.run(VectorizeToPolygonsPlugIn.java:170)
at
com.vividsolutions.jump.workbench.ui.task.TaskMonitorManager$TaskWrapper.run(TaskMonitorManager.java:151)
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