Thought I'd pitch in my 2c work. This seems like good work to do. The various geometry function plugins evolved over several years, which has led to a bunch of inconsistencies. It would be great to get this all cleaned up.
I have a few further answers: 4 & 5. As Michael wrote, Simplify D-P uses the standard Douglas-Peucker algorithm for simplication of *individual* geometries. This algorithm is not guaranteed to preserve polygonal topology, which is why JTS also offers a Topology-Preserving Simplification algorithm. This is the one that is provided as "Simplify (preserve topology)". IMHO, these should be packaged into a single menu item which supplies a dialog to choose between them. As Michael said, S(pt) doesn't work for polygonal coverages - this would be a useful extension. 3: Mostly this is due to the varied history of plugin development. A standard terminology would be nice to have. I'm not sure it's possible or helpful to try and get every spatial functions appearing in only one menu function. There's often different behaviours for the ways in which functions are invoked, which can be useful. But it would be good to minimize the confusion, as long as no functionality is lost. Martin Uwe Dalluege wrote: > Hi, > > this is an attempt to get a summary of all geometry-functions. > The first block shows the programs and the second block the functions > with the number of programs. > Behind the programs you can see the different notations for the layers, > functions and parameter.. > After this litttle work I have some questions: > > 1. What is the different between Tools>Analysis and Tools>Queries? > 2. Buffer is (one time) under Tools>Generate but Union (one Layer) is > under Tools>Analysis? > 3. Is there a reason why we have different notations (for example): > Source, source layer, Layer A, Layer, Source Layer? > 4. What is "Simplify D - P"? > 5. What is "Simplify (preserve topology)"? > 6. Thank you for your help! > > > > 1 = Tools>Analysis>Geometry Functions (Source, Function, Parameter, Mask) > 2 = Tools>Analysis>Join Attributes Spatially (target layer, source > layer, ...) > 3 = Tools>Analysis>Overlay > 4 = Tools>Analysis>Spatial Join of Geometries (Layer A, Relation, > Parameter, Layer B) > 5 = Tools>Analysis>Union > 6 = Tools>Analysis>Union by Attribute Value > 7 = Tools>Generate>Buffer > 8 = Tools>Generate>Convex Hull > 9 = Tools>Generate>Convex Hull on Layer > 10 = Tools>Generate>Create Thiessen Polygons > 11 = Tools>Queries>Simple Query (Layer, Operator, Value) > 12 = Tools>Queries>Spatial Query (Source Layer, Relation, Mask Layer, > Parameter) > > > Boundary 1 > Buffer 1, 7 > Centroid of Source 1 > Contains 2, 4, 11, 12 > Convex Hull 1, 8, 9 > Covers 4, 12 > Crosses 4, 11, 12 > Difference A -- B 1 > Difference B -- A 1 > Disjoint 4, 12 > Envelope 1 > Equals 4, 12 > Is Covered by 2, 4, 12 > Is Disjoint 11 > Is Includet in 11 > Is Within Distance 4, 11, 12 > Interior Point 1 > Intersects 1, 2, 3, 4, 11, 12 > Line Merge 1 > Line Sequence 1 > Overlaps 4, 11, 12 > Polygonize 1 > Reverse Line Direction 1 > Simplify D -- P 1 > Simplify (preserve topology) 1 > Similar 4, 12 > Symmetric Difference 1 > Thiessen Polygon 10 > Touches 4, 11, 12 > Union with one Layer 5 > Union with two Layers 1 > Within 4, 12 > > > > Regards, > > Uwe > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Jump-pilot-devel mailing list > Jump-pilot-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel > > -- Martin Davis Senior Technical Architect Refractions Research, Inc. (250) 383-3022 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
