Michael Sumner

Recently Published

fun with Voronoi
Tidy-only segment decomposition - #2
Turn sf m-poly layer into segments, first with tidyr gather/spread join, then with silicate SC. The performance is compelling.
Tidy-only segment decomposition
Turn sf layer into segments, first with tidyr gather/spread join, then with silicate SC. The performance is compelling. The first needs to clean up row_per_path.
silicate multipatch
The silicate TRI and SC models applied to a 3D multipatch shapefile of NYC building footprints.
Polygon constrained triangulation via ear clipping
rgl lines
p5 volcano
Plotting contours of the volcano data set with p5
Earcut in R
Using V8 to drive the js Mapbox earcut library for polygon ear-clipping triangulation
TMS with raster/rgdal
sf and deldir
Plot Tasmania
silicate topology
segments, edges, nodes and arcs in silicate - this doesn't explain much but it's a happy preview of where things can go
track KDE
simple space-time KDE with stkde
New in ggplot > 2.2.1
tidync select_var
silicate topology
Arc-node basics
silicate finally has a sensible basis for decomposing neigbouring polygonal features to arc-node form
Noded polygons
Topology of shared boundaries between neighbouring polygons requirings "conforming elements" where all edges are atomic
The Raster Abstration (WIP)
a work in progress outline of the basics of raster in R
proto silicate-for-osm
rgdal now has HDF5 amongst others for the Windows binary build on CRAN, making it more consistent with general facilities across platform
mesh topology for OpenGL in R
A relief map of North Carolina counties from a few lines of R code. In-development package
drop large triangles
silicate rationale
Argument for a general common form, a normalization of complex hierarchical structures such as planar shapes
throw away
mesh plot
consistent polygon/raster lossless reprojection via mesh plot
comparison of AIC from gam
gam seems to return AIC in several different ways, unclear what each means
El Windows
El Capitan
El Debian
ring rewinder example2
Re-wind polygons to remove internal boundaries
This does my head in because it juggles relational ids of segments and the structure id of the paths they must take to join together in turtle form. It's just a record to show a basic working example, to be tidied up
tidync for thredds
Seasonal sea ice trends
Draft geo-faceted summary of sea ice changes
tidync and noaaErddap
tidync all variables from a given grid
library(tidync) f <- tail(raadtools::sstfiles()$fullname, 1) library(dplyr) tab <- tidync(f) %>% hyper_tibble(lon = lon > 50 & lon < 100, lat = lat > -75 & lat < -45) %>% dplyr::select(anom, err, ice, sst, lon, lat) library(tidyr) tablong <- tab %>% gather(variable, measure, -lon, -lat) %>% dplyr::filter(! library(ggplot2) ggplot(tablong, aes(x = lon, y = lat, fill = measure)) + geom_raster() + facet_wrap(~variable)
finite element reprojection
Reprojecting after decomposition to smaller pieces to avoid wrapping issues
tidync NetCDF and dplyr::tbl_cube
Sample output from a 4D ocean model, using tidync to pass tbl_cube data to ggplot2
geofacet grid hack
raadtools leaflet extras
3D convex hull etc
spdep from scratch
Distance to coast
Decomposition to triangles to apply continuous measures via finite elements
Tidy NetCDF prototype
hyperslab read NetCDF with dplyr idiom
filtrate is a function to define the hyper slab index in a NetCDF
sf union
tidync early experiment
Raster extract is amazing for extraction of grid values with cell indexes, this seems under-used in R and it's partly because it's tricky to juggle the outputs of the index-building functions.
AMSR sea ice Arctic polar stereographic
Basic georeferencing of the standard grid used for passive microwave sea ice products. As per
Fill between lines
filling between lines is a dark art
angstroms - early examples
Working with ROMS in R, angstroms package
Raadtools extraction
R Mapping Tips
Mapping broad-scale marine stuff
Polygon monotones
neighbours - set
neighbours by join, for all nc counties
neighbours by join
ACE Ecosystems compute
polygon textures
Inside-out nesting
The tidyr::nest tables perform version of normalization, to reduce duplication in data. This document illustrates an "inside-out" version of the nest process to produce two tables.
sf ggraph
Simple features topology with ggraph
Graticule auto-experiments
sf vs sp plotting
This document shows a migration of exsting sp code to the 0.2-7 (CRAN now has 0.2-8). The dev version of sf requires significant changes to get the same result.
Leaflet - TopoJSON
Albers Equal Area Conic with Antarctica from R, no cartographic catastrophe.
ROMS Mapping
plotting ROMS data with R in a few different ways
Automatic Graticules
Polygon with holes with topography
Polygon decomposed to small triangles, merged with global topography, plotted with plotly
rangl plotly
Build mesh from maps for plotly
Spatial normal forms
A long description of the lack of topology in spatial data structures, and development tools to convert to mesh/network data structures while keeping the database-object framework common to GIS.
Nesting spatial
FTCA 1967 timeline 01
A timeline of the bushfire extent on 7 February 1967
Leaflet draw projection
Simple features at the zoo
Incomplete survey of building and plotting polygons with holes