On Thu, 2008-01-31 at 09:00 +0200, Maris Nartiss wrote: > I'm sorry to interrupt Your advanced discussion, but if there are just > some "holes" that are required to be converted to polygons, then why > not use v.digit? Simply digitising new centroid inside a hole > (enclosed from other polygon boundaries) will turn hole into polygon.
Yes, it is simple(r). And there is no need to "save as shapefile" and re-import in GRASS the modified vector file. > > WBR, > Maris. > > 2008/1/31, Nikos Alexandris <[EMAIL PROTECTED]>: > > Hi! > > > > On Wed, 2008-01-30 at 23:52 +0200, David Epstein wrote: > > > Hi Nikos, > > > > > > Thank you for that suggestion. Indeed, I did NOT realize that v.extract > > > was used to create new geometry in a layer. However, I too need some of > > > the islands (is there a technical difference between island, hole, and > > > missing polygon?). > > > > I am not sure! > > > > Would be nice to have a kind of GRASS-GIS lexicon with (basic and > > non-basic) definitions! > > > > * island... I suppose are small poylgons within larger ones > > > > * holes... just "nothing" within larger polygons > > > > * missing polygon... ? > > > > > > > > There is a single missing polygon that I now have attribute data for and > > > I want to create the polygon (from the existing points and lines) and > > > fill-in the related attribute fields. > > > > > > I imagined some sort of interactive process of clicking on the relevant > > > bounding elements and *presto* the polygon would jump into existence. I > > > tried this in v.digit but was not able to get the desired result. > > > > If you just need to quickly correct a small number of polygons try with > > the "fresh-baked" QGIS (r0.9.2.rc1), which works as a GRASS frontend. > > > > 1. you need to add in your /etc/apt/sources.list following source: > > deb http://ppa.launchpad.net/timlinux/ubuntu gutsy main > > > > 2. sudo aptitude update && sudo aptitude upgrade > > > > --- if not already installed... "sudo apt-get install qgis > > qgis-plugin-grass"--- > > > > 3. Load GRASS plugin > > > > 4. Open your GRASS mapset within QGIS > > > > 5. Load your vector (polygon) file > > > > 6. Play with the tools... ( I have seen the new digitising tools... must > > be really what you are looking for!) and edit your polygons. > > > > *** You need first to "right click" on your vector layer and "save as > > shapefile" -- Then you can edit. 7. Re-import in GRASS with v.in.ogr > > > > > > > > > > > > This is a really basic step that people do several times a day, right? > > > > > > -david > > > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user -- Nikos Alexandris . Department of Remote Sensing & Landscape Information Systems Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg . Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris . Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
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