Constrained simplification of arbitrary polylines in the context of arbitrary planar geometries. Download and try it on Windows, Linux or Mac.
Open a terminal (command line) from the directory containing an executable (constdp[.exe] for 64bit, constdp_32bit[.exe] for 32bit systems). Simplification options are made available through the use of a TOML file (config.toml). Execute constdp with the following command :
./constdp -c ./config.toml If a -c option is not provided at the terminal e.g. ./constdp, it assumes ./config.toml as the default configuration file. Change config.toml to configure your simplification.
# input file is required
Input = "/path/to/input.[wkt]"
# output is optional, defaults to ./out.txt
Output = ""
# this is optional
Constraints = "/path/to/file.[wkt]"
# type of simplification, options : DP, SED
SimplificationType = "DP"
# simplification threshold (in metric units as input geometric coordinates)
Threshold = 0.0
# minimum distance from planar contraints - provide value if `DistRelation = true`
MinDist = 0.0
# relax distance for non-planar intersections - provide value if `NonPlanarSelf = true`
RelaxDist = 0.0
# are polylines independent or a feature class ?
# if false planar and non-planar intersections between polylines are not observed
IsFeatureClass = false
# observe planar self-intersection
PlanarSelf = false
# observe non-planar self-intersection
NonPlanarSelf = false
# avoid introducing new self-intersections as a result of simplification
AvoidNewSelfIntersects = false
# observe geometric relation (intersect / disjoint) to planar objects serving as constraints
GeomRelation = false
# observe distance relation (minimum distance) to planar objects serving as constraints
DistRelation = false
# observe homotopic (sidedness) relation to planar objects serving as constraints
SideRelation = falseInput in config.toml should point to a text file containing WKT strings or toml arrays.
LINESTRING (30 10, 10 30, 40 40)
# linestring with 3d coordinates (x, y, time)
LINESTRING (30 10 1, 10 30 2, 40 40 3)
See sample input and constraints WKT text files : Input, Constraints.
1=[[30, 10], [10, 30], [40, 40]]
2=[[30, 8], [10, 15], [40, 25]]
#lines with 3d e.g.: (x, y, time)
3=[[30.1, 8.2, 2.4], [10.4, 15.9, 5.6], [40.8, 25.0, 9.8]]Note that the toml input uses an id=array, contents of the array must be of the same type (all coordinates as integers or floats). A point is [x , y] or [x, y, z]. A polyline is a string of points [[x,y],[x,y],...]. A polygon is a string of of polylines:
[string 1, string 2, ...] == [[[x,y],[x,y],...], [[x,y],[x,y],...], ...];
the fist is a shell (outer boundary) and subsequent strings are interior holes (for polygon with holes).
For example,
WKT string:
POLYGON ((35 10, 45 45, 15 40, 10 20, 35 10),(20 30, 35 35, 30 20, 20 30))
TOML arrays:
1=[[[35, 10],[45, 45],[15, 40],[10, 20],[35, 10]], [[20, 30],[35, 35],[30, 20],[20, 30]]]See sample input and constraints toml text files : Input, Constraints. Since constraints can be of the form point, polylines, or polygon its toml is of the format:
[points]
id=array
id=array
[polylines]
id=array
id=array
[polygons]
id=array
id=array Given a polyline in resource/input.wkt
Input = "resource/input.wkt"
Output = ""
Constraints = "resource/constraints.wkt"
SimplificationType = "DP"
Threshold = 50.0
MinDist = 20.0
RelaxDist = 30.0
IsFeatureClass = false
PlanarSelf = true
NonPlanarSelf = true
AvoidNewSelfIntersects = true
GeomRelation = true
DistRelation = true
SideRelation = trueOriginal polyline in the context of planar objects:
Constrained simplification with respect to config options(above):
Unconstrained simplification with these options turned false:
IsFeatureClass = false
PlanarSelf = false
NonPlanarSelf = false
AvoidNewSelfIntersects = false
GeomRelation = false
DistRelation = false
SideRelation = false