Hi,
> <snip> > > I did some experiments with shapely and I'll like to ask (for now), if it > > would be possible: > > - for the .project method to return the actual point (in LineString) as > well > > as its distance? I think the API is easier to understand if methods do only one thing. > I do agree. However project as a methods name implies (at least for me) that it would return a point when we are projecting points. > We can always follow up with a call to interpolate. In many (probably > most) cases, we'll know that point already. > However when you are constructing new geometries, you may need to create helper geometries. Then it would be handy to be able to grap to some of the "intermediate" results as well. > > > - for the .project method to accept MultiPoints as well? > > And return a list of distances? I think this increases the complexity > too much. Given a linestring and multipoint like > > >> from shapely.geometry import * > >>> a = LineString(((0, 0), (10, 10))) > >>> b = MultiPoint([(i, i) for i in range(11)]) > > it is simple to gather distances and interpolated points together like this > > >>> [(a.interpolate(d, True), d) for d in [a.project(p, True) for p in b]] > [(<shapely.geometry.point.Point object at 0x73b570>, 0.0), > (<shapely.geometry.point.Point object at 0x73b390>, > 0.10000000000000001), (<shapely.geometry.point.Point object at > 0x73b770>, 0.20000000000000001), (<shapely.geometry.point.Point object > at 0x73b550>, 0.29999999999999999), (<shapely.geometry.point.Point > object at 0x73b5b0>, 0.40000000000000002), > (<shapely.geometry.point.Point object at 0x73b5d0>, 0.5), > (<shapely.geometry.point.Point object at 0x73b5f0>, > 0.59999999999999998), (<shapely.geometry.point.Point object at > 0x73b6b0>, 0.69999999999999996), (<shapely.geometry.point.Point object > at 0x73b810>, 0.80000000000000004), (<shapely.geometry.point.Point > object at 0x73b830>, 0.90000000000000002), > (<shapely.geometry.point.Point object at 0x73b850>, 1.0)] > I just try to avoid pure python loops. Especially when dealing with intermediate geometries, it would be nice if python could act as efficient "glue". > > > - to add method .extrapolate (similar than .interpolate) but operates > > outside the end points as well? > > > > This I do like. > > > I do realize tough that above kind of functionality may not be relevant > for > > majority of shapely users. However shapely could just be the "common > > denominator" for many different pythonical geometrical "packages". I do > also > > agree with the Zope's component philosophy, just hoping interfaces would > be > > part of the "official" python. > > > > Are there people needing/ interested of additional geometrical > operations/ > > primitives (on top shapely, without infering its current functionality)? > If > > so, perhaps we could discuss more detailed manner on the requirements. > > > > > > Regards, > > eat > > Good idea. PostGIS, for example, has a bunch of useful functions that > are additions to the standard OGC methods. See > http://www.postgis.org/docs/ch08.html. The sub-linestring function, > for example, could be handy. > Sub-linestring functionality would indeed be handy. Even more so if you could specify any start and end value from (-inf, inf). Do you see any possibilities to interface directly with PostGIS from "outside of SQL"? Does there exist any major functionality in the geos-library not yet supported by shapely? > > -- > Sean > > > Regards, eat
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