Hello Jason, For both TopologyPreservingSimplifier and DouglasPeuckerSimplifier the distance tolerance refers to the distance of any vertex in the output (simplified) geometry from the input geometry. It is not the distance between vertices in the output, and not necessarily the distance between input and output vertices.
Michael On 25 May 2011 00:51, Jason Ferguson <[email protected]> wrote: > I seem to be doing something wrong here, but it may just mean that I > don't understandard what values to use when calling simplify(). > > I used the values of 1.5, 0.5, and 0.1 for a distance tolerance, but > it simplified a feature with 1900 points to _6_ points, which is a bit > too much. Can anyone give me pointers on what to use? > > Jason > > On Tue, May 24, 2011 at 5:57 AM, Jason Ferguson <[email protected]> > wrote: >> Okay, it's looking like TopologyPreservingSimplifier is what I need. >> However, a question: how do I determine what value to use for the >> distance tolerance? The only example I found used a value of 0.1, so I >> don't know if that simplifies to 0.1 (meters/feet/whatever), or it >> means something else. In general, I'm happy with 1.5 Meters or 5 feet >> or so. >> >> Jason >> >> On Mon, May 23, 2011 at 9:58 PM, Jody Garnett <[email protected]> wrote: >>> JTS does provided a Precision object you can use with a Gometry factory to >>> explicitly control precision. That combined with simplify geometry >>> operations should give you the control you need? >>> Note we also make use of "decimation" to skip over points that would >>> otherwise render into the same pixel; perhaps that code could be a useful >>> example for you? >>> While there is a page in the user guide >>> (http://docs.geotools.org/latest/userguide/library/jts/simplify.html) I >>> could really use a code example if you can produce one :-) >>> >>> -- >>> Jody Garnett >>> >>> On Tuesday, 24 May 2011 at 10:47 AM, Jason Ferguson wrote: >>> >>> I am attempting to store data from the TIGER/Line shapefiles into a >>> database table, but am having issues with reducing the precision from >>> the 5 decimal places to 3 decimal places. >>> >>> What I find is that after I dig down and get the coordinates, then >>> eliminate duplicates, I'm left with a list of coordinates something >>> like this (which I call semi-duplicates for lack of a better term): >>> >>> 45.900, 178.353 >>> 45.900, 178.355 >>> 45.900, 178.361 >>> 45.900, 178.363 >>> >>> I end up with the same latitude, but several intermediate longitudes >>> (or vice versa). I don't need all of these intermediate points, but I >>> realize that this is an artifact of brute force rounding. >>> >>> Is there a "better" way to reduce the decimal precision? >>> >>> Jason >>> >>> ------------------------------------------------------------------------------ >>> vRanger cuts backup time in half-while increasing security. >>> With the market-leading solution for virtual backup and recovery, >>> you get blazing-fast, flexible, and affordable data protection. >>> Download your free trial now. >>> http://p.sf.net/sfu/quest-d2dcopy1 >>> _______________________________________________ >>> Geotools-gt2-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users >>> >>> >> > > ------------------------------------------------------------------------------ > vRanger cuts backup time in half-while increasing security. > With the market-leading solution for virtual backup and recovery, > you get blazing-fast, flexible, and affordable data protection. > Download your free trial now. > http://p.sf.net/sfu/quest-d2dcopy1 > _______________________________________________ > Geotools-gt2-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > ------------------------------------------------------------------------------ vRanger cuts backup time in half-while increasing security. With the market-leading solution for virtual backup and recovery, you get blazing-fast, flexible, and affordable data protection. Download your free trial now. http://p.sf.net/sfu/quest-d2dcopy1 _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
