Okay so the example is going through the steps of drawing a geometry onto the screen. There are not one by *two* steps involved. 1. from data to world 2. from world to data
I am going to change the title of this section to make that clear... do the concepts make sense to you? Here is some examples for making a geometry: - http://docs.codehaus.org/display/GEOTDOC/01+How+to+Create+a+Geometry That said it looks like you are using RendererUtilities and MapContexts and a bunch of stuff I have not figured out yet; chances are it is doing all these steps in side those methods.... > Hi all: > > I was trying to fix an example[1] but I'm lost in the dark. The example > says: > > Geometry screenGeometry = geometry.transform( screenCRS, transform ); > > But I don't know how to get a Geometry, so I go to the Geometry section > in the user manual[2] but: > > GeometryBuilder builder = new > GeometryBuilder(DefaultGeographicCRS.WGS84); > > it doesn't work because org.geotools.geometry.GeometryBuilder package > (I'm using 2.3) doesn't exist. > Use the JTS Geometry classes (as shown in the link above): > And even if I get this working: how can I create the screenCRS? > Um? Based on your graphics object (is it a window?) you are drawing onto? > I've look at the source code of > RendererUtilities.worldToScreenTransform but it's not applicable to make > a simple example. > Perhaps this is not the best example to make the point - the point is use the CoordinateReferenceSystem and MathTransforms. > Please. I need help in A LOT of simple things. I will send then back to > the list as _working_ code snippets so the user manual gets updated and > other people can learn from my faults. > No worries; I banged out that example based on a very common bit of confusion (ie that there is an x axis). I really appreciate the feedback. > Thanks! > > > P.S: IMHO the user manual has many "underexplained" examples. That is actually by request; the previous set of documentation had so much explanation it confused people (and nobody felt smart enough to contribute). > It's very hard to a newcomer to learn how to use GeoTools in deep. Indeed; I do hope that separating out the GIS from the programming will make things clearer; if you are interested we do have writing guidelines for the user guide. > I know many of you life from supporting GeoTools by contract, but I also > think that > having a good documentation would make that a lot of people use the > library and this will end in many more company programmers using > GeoTools, programmers from companies that will pay you for support. :) > No worries; I have been doing this user manual on my own time. Mostly based on answer questions on the user list here. Jody ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
