- Dissolve polygons in r sf by_feature: logical; if TRUE, union each feature if y is missing or else each pair of features; if FALSE return a single feature that is the geometric union of the set of features in x if y is missing, or else the unions of each of the elements of the Cartesian product of both sets Aug 25, 2023 · Everything looks great, except that there are internal boundaries within Russia where it crosses the 180th meridian, and it appears that st_union() won't dissolve polygons across that boundary, at least as I am using it. Here is a minimal example Jul 26, 2012 · After converting a raster file to polygon (using gdal_polygonizeR NOT rasterToPolygon due to runtime issues), I have been able to 'Dissolve Boundaries' of individual polygon features within the same layer ('poly' in code below) by applying the following steps (NB: I have provided example output related to the number of features in the output datasets change after specified functions are run): Sep 27, 2021 · In my opinion, the sf package is the premiere tool for working with spatial data in R. The code below is the one I am playing with Arguments x. Creating sf polygons from a dataframe. finding the centroid of a polygon, detecting whether pairs of feature geometries intersect, or find the union (overlap) of two polygons. Dissolve holes in polygon in R. I have tried the functions gUnion and gUnaryUnion included in the rgeos package. Apr 3, 2019 · Have the shape file which has multiple polygons with logical division of Zones and Plots. Sep 22, 2023 · I am trying to extract touching polygons using R. object of class sf, sfc or sfg (optional). However, by flattening the entire dataset into one multipolygon then casting back out into individual polygons, we lose all the info about each original row (e. sf method actually uses the st_union function under the hood, but in the case of this shapefile the alignment seems imperfect. I am trying to "dissolve" (fuse, merge) the spatial polygons of a shapefile by a certain code that is loaded from a csv file (e. The canonical examples are mean and sum. 999 0. Arguments x. Below is what I've tried so far. Mar 22, 2023 · The easiest way might be to generate the buffer zone (just the outer part), rasterize it, assign raster cells to nearest polygon ID, then polygonize, then join to the original polygons and dissolve on polygon ID aggregate an sf object, possibly union-ing geometries. If I were to do one grid Oct 28, 2020 · Intersection of polygons in R using sf. 0 R SF: Transforming the format of sf geometry. May 13, 2023 · I am trying to plot the boundaries from this geojson file. This can be changed using something like: sf::st_set_precision(1e8) Apr 7, 2021 · I am having trouble finding the best way to merge multiple sf polygons into one new sf polygon. On a much smaller scale (100 points) usin Mar 15, 2021 · In R, we can apply this sort of simplification with a few functions from the packages sf and, for some special cases explained below, rmapshaper. Simplifying polygons in rgeos and maintaining data in Aug 10, 2023 · I'm trying to aggregate a simple features collection using a group variable that is a factor. buff, as I one was to nbrs. The second argument should be a data. 017). 1 m works for cleaning these kind of polygons. Follow Dissolve holes in polygon in R. Using st_intersection and then aggregating by row ID seems viable, but I’m unsure how to do the aggregation procedure. COMMENT I was using dplyr::summarize() on a large (3. Here plots are on top of the Field Zones. When I use st_touches(), it gave all (empty) value. y: object of class sf, sfc or sfg (optional). I have tried the code below but it creates both linestring and multilinestring types. In this walkthrough I would like to share the process in a workflow I built on the sf package. st_union seems appropriate only for aggregating together ALL interesting polygons to a single mass polygon. overlaps (FALSE/TRUE) Dissolve overlapping polygons, negates using attribute Apr 3, 2017 · There currently doesn't seem to be a dissolve feature as part of sf. Load 7 more Mar 30, 2020 · R sf aggregate polygons at various geographic levels. dots. A dissolved POLYGON or MULTIPOLYGON object. For point layers, replaces a group of points with their centroid. However, there is no dedicated sf::st_dissolve(). May 13, 2017 · Stack Exchange Network. Plots are overlapping over Zones. If y=NULL all polygons will be dissolved into a single attribute, unless there is spatial discontinuity (eg. Put another way, I want to combine neighboring polygons but exclude the polygon that touches all its neighbors. Nov 18, 2023 · Dissolve polygon feature calss. 9. x: An sf POLYGON or MULTIPOLYGON object. Jun 19, 2020 · r-sf; r-sp; Share. Hot Network Questions Aug 13, 2019 · I would like to merge/combine/union different features within a shapefile by attribute value. object of class sf. Nov 22, 2020 · Doesn't actually seem like any of the lines after the polygons layer is changing the map, but I'm fine with that if I can get rid of the census tract lines. Yep - small gaps. Modified 4 years, 11 months ago. Aug 31, 2022 · As I commented, your problem might be solved by buffering -which means to extend the polygon homogeneously-, dissolve and then use a negative buffer to approximately restore it to its original size; your polygons had remarkably large gaps of around 100 m, usually 0. A pair of data frames, data frame extensions (e. FUN should be a function that takes as first argument a vector, and that returns a single number. envelope. In the past it took 16 hours. 013 0. see corresponding function in package dplyr. , gaps) in the data. file ("ex/lux. I hope to remain within the sf environment. shp", package = "terra") p <-vect (f) p ## class : SpatVector ## geometry : polygons ## dimensions : 12, 6 Apr 10, 2018 · I want to find the fastest way to union a set of polygons into one large polygon. Hi, I am a student in spatial data. If you imagine a Venn diagram – the part in the middle where the circles overlap is erased, leaving the parts that don’t overlap. Feb 15, 2018 · Depending upon the shapefile I need to either dissolve by group or just use st_union for all. from 4000 to 3900 if say 200 polygons overlap pairwise. Apr 4, 2024 · x: An sf POLYGON or MULTIPOLYGON object. Below is a simple example. list of polygons of class extending SpatialPolygons, or an sf or sfc object containing non-empty (multi-)polygon objects row. names character vector of region ids to be added to the neighbours list as attribute region. 5 gb) file with just shy of 1 million polygons to do a dissolve. 2. May 21, 2014 · My question here is also how to deal with bad polygon data in R – Pascal. Something like the procedure below might work (watch out for typos) library (sf) # extract the geometry of the conservation areas to a new variable # to get rid of all other attributes polygon_outlines <- st_geometry (conservation_area_polygons) %>% st_as_sf() # add a new field to the polygon_outlines to identify points within or without # so points that Apr 10, 2018 · I want to find the fastest way to union a set of polygons into one large polygon. 9 f <-system. #' @title Dissolve polygons #' @description Dissolve polygon feature calss #' #' @param x An sf POLYGON or MULTIPOLYGON object #' @param y An attribute in x to dissolve by, default is NULL #' @param overlaps (FALSE/TRUE) Dissolve overlapping polygons, negates using attribute #' #' @details #' If a dissolve attribute is defined, the result will be a #' MULTIPOLYGON with the grouping attribute I want to dissolve some polygons, and I am doing the following: Batching in the shapefile (DA. x: object of class sf, sfc or sfg. I would now like to take that polygon file and merge any polygons containing less than 6 pixels with its Jun 2, 2017 · I created a spatial polygon file from a gridded dataset using the grid2polygons function in R. point_order. Commented Feb 18, 2015 at 12:01. object of class sfc or sfg containing a POLYGON with the envelope for a voronoi diagram; this only takes effect when it is larger than the default envelope, chosen when envelope is an empty polygon. Dissolve polygon feature calss. 5, 1. 2 Jun 7, 2024 · You got close, but there was one thing you needed to factor in. Aug 13, 2016 · I would like to dissolve only the overlapping features into separate polygon features (one feature per par of overlapping polygons) and preserve the other features as they are. Similar threads I’ve quered: Dissolve only overlapping polygons in R Jul 19, 2022 · A polygon or set of polygons that is composed of only the group-level. buff geometry!!! when I create u = st_union(rbind(nbrs. Nov 13, 2022 · Then, I create buffers around the fields using sf::st_buffer(). I am able to plot all the boundaries using sf in R. The dissolve using the geos Sep 24, 2020 · The main issue is that there is a hole in one of my polygons, but I can't figure out how to make an sf object where this hole is recognized and where I can specify the correct crs. 0 Transform a sfc_LINESTRING geometry to sfc_MULTIPOLYGON . then converted back to sf using sf::st_as_sf(). Ask Question Asked 12 years, 5 months ago. see corresponding function in dplyr. Modified 8 years, Removing holes from polygons in R sf. . 2)), sq(c(0,0)), sq(c(1, -0. add. 2,4. Here is spplot of the shape file. id , default seq(1, nrow(x)) ; if pl has row. sf dissolve/remove inner borders of POLYGON. Is there a better way to go? Mar 19, 2018 · This works great! And thanks for the tip on sf! Is there a downside to loading a shapefile in sf? I'm getting crazy loading performance differences (Ethiopia 2 in rgdal: user system elapsed 0. I was wondering if i can randomly dissolve polygons, that are from the same dataset, in Rstudio. 0. This question has been asked before here: Dissolve only overlapping polygons in R but I am looking for an approach that uses the sf package. In this example, we dissolve all polygons to create a single outline of the state of Maine. How can I dissolve the boundaries so that they don't show up on my map? I would prefer answers that use sf. This tutorial demonstrated how to: (1) read in, transform, and minimize a shapefile; (2) select a single state’s counties from the Census Bureau cartographic boundaries file; (3) plot a shapefile using the simple plot() function; (4) dissolve internal boundaries of a state using the dplyr::group_by() function and the sf::st_union() function; (5) calculate the geographic centers type transformations (e. Example: all counties within the same metropolitan statistical area will be dissolved into one polygon with geometry only for said MSA. R sf: st_intersection on a list of polygons. I have a shapefile with about 1500 polygons. The function union_sf takes as required arguments a sf data frame (in the first position, so it is pipe friendly) and a name of a column. 4 Can R merge latitude and longitude points to areas in spatial polygon? 3 Merge two polygon regions into a single polygon region in R May 5, 2022 · contour_poly <- as. The reproducible examples is as follows - three clusters of rectangles of which two have overlap: sq = function(pt, sz = 1) st_polygon(list(rbind(c(pt - sz), c(pt[1] + sz, pt[2] - sz), c(pt + sz), c(pt[1] - sz, pt[2] + sz), c(pt - sz)))) x = st_sf(box = 1:6, st_sfc(sq(c(4. 4. The length of my dataset should therefore reduce e. sf, 'POLYGON') not give you what you want? – mrhellmann. g. frame( lon = c(0, 1, 1, 0, 0, 0, 1, 1, 0, 0 Mar 18, 2019 · Also, since it looks like most polygons intersect most others, if the result could be computed it would have on the order of (# polygons)^2 holes - or about 100M holes! It's highly unlikely this could be computed or represented. Jun 24, 2017 · R returns an error when I try to dissolve polygons' boundaries using the summarize function in the sf package. Let’s get started. If you st_buffer() %>% st_difference each polygon will get buffered (filling in the gaps) and then the st_difference cleans everything up so that the shared boundary is the same. Obviously, this is a rather clumsy workaround. Instead you can simply define a grouping variable in your data and use dplyr::group_by and dplyr::summarize. I want to aggregate census sectors by modelo and cnes, to create another dataset with new boundaries. May 16, 2019 · I want to union all polygons that overlap with other polygons. I would now like to take that polygon file and merge any polygons containing less than 6 pixels with its I am used to Linux and programming in C, but not to R and its syntax. Ask Question Asked 4 years, 11 months ago. The polygons are some wall facades and gaps. To dissolve all polygons that share at least one line segment, simply pass the object name to sf’s st_union function while making sure that the by_feature option is set to FALSE. I have used dissolve=TRUE in the terra::as. Another bonus would be if it happens in a spatially constrained way. Each SpatialPolygonsDataFrame contains about 500 polygons. This is slightly different if you want to merge contiguous members of the tract together, but all you would have to do is remove the first element (the entire state) from the polygon, and then run gUnaryUnion on the remainder, and then re-add the contiguous tract members to a copy of the gUnaryUnion-ized state. logical; if TRUE, union each feature if y is missing or else each pair of features; if FALSE return a single feature that is the geometric union of the set of features in x if y is missing, or else the unions of each of the elements of the Cartesian product of both sets dissolving the inner polygon (the center) dissolving the outer polygon (the outskirts) joining the center and outskirts back to one sf data frame; One important hack that I learned is to extend (buffer) the borders of the city neigbourhoods by half a meter. , to join counties' polygons by its FIPS State code to obtain a single polygon(s) for each State). Oct 5, 2018 · @noriega You can load the sahpefile into R with sf::st_read("your_shapefile. Dissolving polygon features with the sf Dec 11, 2020 · If two polygons overlap then this function allows you to remove the overlapping areas from two polygons. Each polygon has a property code. Here is a minimal example of how that function might work. Something like the procedure below might work (watch out for typos) library (sf) # extract the geometry of the conservation areas to a new variable # to get rid of all other attributes polygon_outlines <- st_geometry (conservation_area_polygons) %>% st_as_sf() # add a new field to the polygon_outlines to identify points within or without # so points that library (terra) ## terra 1. x, y. polygons(patches(my_spat_raster > 1), dissolve = TRUE) and some other variations captured from similar threads, but nothing seems to reproduce it. polygons(, dissolve=TRUE) step because I want to aggregate all the fields/gridpoints together. shp - sensitive information hence first two sample records and only first three columns shown) Batchin Nov 30, 2018 · I have a tidy dataset for census sectors in sf format (setores_sp_ok. First, let’s load the required libraries. This almost works, but creates polygons that overlap with adjacent features. I have tried to do a 250m buffer on a multipart feature and then do a 250m negative buffer. Processing with gUnion is done this way: Aug 5, 2021 · I found that st_within() is a bit slow. However, I would like to merge some polygons together - e. Jul 7, 2013 · I have a list of 300 Spatial Polygons Data Frames in R that I wish to dissolve geometrically. #' @param overlaps (FALSE/TRUE) Dissolve overlapping polygons, negates using attribute #' @details #' If a dissolve attribute is defined, the result will be a Aug 4, 2020 · Is there any way to dissolve lines by a certain column in SF? This is such an easy task in QGIS or ArcGIS. Arguments. by_feature. I've figured out how to do everything but write the revised polygon back to original sf. 1. In the following, I will show how to apply them and what the effects of their parameters are. ignored. How to dissolve polygon in R and transferring original attribute information. Oct 11, 2024 · x: object of class sf, sfc or sfg. data. Feb 28, 2017 · I have a set of polygons of which some intersect and/or touch (common borders). 8)), sq(c(0. Sep 30, 2022 · I'm quite new to geospatial analysis in R and need help with dissolving polygons based on their location. I am still fairly new to the sf-package and haven't been able to figure this out. logical; if TRUE, return lines, else return polygons. y. The task is to dissolve / merge plots with Zones with no overlapping. Aug 10, 2024 · A common GIS task is to dissolve boundaries based on shared boundaries of polygons. Viewed 3k times Aggregates using specified field, or all shapes if no field is given. Aug 16, 2021 · sf dissolve/remove inner borders of POLYGON. buff, one)) (as suggested by @Spacedman) and then run st_difference() it creates correct output! For as far as these functions use package rgeos, (lines, polygons, dissolve = TRUE), they are deprecated as rgeos will retire; try using sf::aggregate instead. , POL_STN_NM = PS RAJ PARK Apr 24, 2018 · I'm trying to remove overlapping areas from multiple polygons using sf like the following: # sample polygon poly <- data. Take the NC county shape in the sf package (imagining it had some gaps). A simple, motivating example would be to recreate state shapefiles from a geographic dataset that inclu create a line sf with just the border between my shapefiles; from this line create a buffer polygon just big enough to cover all gaps; join and dissolve this buffer to the shapefile for neighbours -- NEI; clip off the expanded NEI with the REG shapefile. Here's a view of the menu option in QGIS: Here's a visual of the operation: Related references: Dissolve polygons in R Polygon Dissolve Operations using R ArcMap help o Sep 3, 2015 · We need a shapefile of small geographies to ‘dissolve’, a lookup table to tell us which polygons dissolve into which, and we need a couple of R spatial packages to run everything. I then intersect these buffers with the conserved areas polygon using sf::st_intersection() and calculate their areas. Doing this with R always bends my head a little bit. Dec 10, 2024 · If you're okay with all polygons being dissolved into 1, then you can just use the ms_dissolve() function on the full dataset and then use something like coord_sf(crs = "+proj=moll +lon_0=180 +datum=WGS84 +units=m +no_defs") at the end of your ggplot call. Mar 28, 2022 · Conclusion. 3 #> Jun 2, 2017 · I created a spatial polygon file from a gridded dataset using the grid2polygons function in R. names , they are used instead of the default sequence. # The default behaviour of this script is to create a folder called 'dissolve-example' # and download and run everything from here. rda), which has polygons for two different territorial models, indicated by variable modelo. library(sf) #> Warning: package 'sf' was built under R version 4. edu The usual join verbs of base R (merge) and of dplyr (left_join(), etc) work for sf objects as well; the joining takes place on attributes (ignoring geometries). frame (or similar), not an sf object: Mar 20, 2019 · For a more modern interface using sf the equivalent is sf::st_union. Sep 3, 2015 · We need a shapefile of small geographies to ‘dissolve’, a lookup table to tell us which polygons dissolve into which, and we need a couple of R spatial packages to run everything. The issue is quite specific and you can download the data here data. 003 0. How to merge multiple sf polygons? 2. Van Leuven, vanleuven. 12 Oct 1, 2012 · Dissolve holes in polygon in R. We can get round this by putting a small buffer around each polygon before specifically calling st_union: Feb 13, 2015 · @rcs I try to force gpclib works in R but I could not! Is there any other way to dissolve polygons rather than using gpclib? – Iman . 211 1. 7)), sq(c(3,3)), sq(c(-3 Aug 5, 2021 · I found that st_within() is a bit slow. shp") and use the method suggested by Ibusett. y: An attribute in x to dissolve by, default is NULL. As ne_countries() is an S2 object with full global extent, you either have to st_transform() it to planar coordinates, or turn off sf_as_s2() to return your desired outcome. other arguments. Processing with gUnion is done this way: Mar 11, 2020 · @Mox, great idea!! I don't know how to check for self-intersection problems, but I am sure that they do, as the one vertices completely overlaps with vertices in nbrs. Jun 14, 2022 · I would like to fill in the gaps of multipart polygons to create a single extent polygon for each feature. If a dissolve attribute is defined, the result will be a MULTIPOLYGON with the grouping attribute column. Counting features is obtained when summing an Nov 25, 2015 · Dissolve holes in polygon in R. Commented Dec 15, 2022 at 20:15. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. by_feature: logical; if TRUE, union each feature if y is missing or else each pair of features; if FALSE return a single feature that is the geometric union of the set of features in x if y is missing, or else the unions of each of the elements of the Cartesian product of both sets Jan 7, 2021 · I have rows of respondents within census polygons and am trying to generate first-order aggregated polygons, excluding the census unit a respondent resides in. It would also be nice if i can set the end amount of polygons after the dissolve proces. object of class sf, sfc or sfg. 8. May 27, 2020 · I'm looking for a solution that will let me add a 100m buffer around 2 million points and then dissolve/union that output into a single multipart polygon. As a temporary solution I set lwd = 0, but that of course removes all the lines. , POLYGON to MULTIPOLYGON) affine transformation (shift, scale, rotate) transformation into a different coordinate reference system; geometrical operations, e. 3@osu. , "name" here, but more in the real dataset), and in the real dataset, some shapes are correctly multipolygons. 2. 271, same layer in sf: user system elapsed 0. I am using R's sfpackage to perform operations on polygons. by. a tibble), or lazy data frames (e. The %>% notation works to pipe a bunch of st_union functions, but there must be a different way? Aug 21, 2024 · Hmm, yes, in this case, this fix works. Objective is to produce a polygon that represents the contour thresholds for the specified value throughout the entire SpatRaster. either a list of grouping vectors with length equal to nrow(x) (see aggregate), or an object of class sf or sfc with geometries that are used to generate groupings, using the binary predicate specified by the argument join Sep 1, 2020 · I have a polygon dataset in Simple Feature format that I dissolve based on a ID column like this, using the sf package with R: small_polygons <- small_polygons %>% group_by(dissolve_id) %>% summarise() Oct 11, 2024 · sf: Create sf object; sfc: Create simple feature geometry list column; sf-defunct: Deprecated functions in 'sf' sf_extSoftVersion: Provide the external dependencies versions of the libraries sf-package: sf: Simple Features for R; sf_project: directly transform a set of coordinates; sgbp: Methods for dealing with sparse geometry binary Jun 12, 2017 · How do I simplify an sf polygon without introducing gaps and slivers? With a shapefile, for example, I would use rmapshaper::ms_simplify(): Dec 16, 2022 · When dissolving polygons you need a variable to dissolve by; for a more detailed walktru consider this earlier blog post Merging Geometry of {sf} Objects in R · Jindra Lacko In your case - when one of your desired polygon groups seems to have only a single member - you could go by name of the isolated island polygon. However, they do touch each other. I assume this is what you are looking for. overlaps (FALSE/TRUE) Dissolve overlapping polygons, negates using attribute x: An sf POLYGON or MULTIPOLYGON object. type transformations (e. Jan 16, 2023 · The sf:::summarise. Here is a reproducible example using the NC dataset from the sf package. Two optional arguments - tolerance and planarCRS - are used in the process of buffering the original polygons to avoid slivers. I have been using st_union however that seems to only merge two sf objects pairwise. May 21, 2019 · I have an sf table where I need to extract one of the polygons, clip it to a bounding box, and then write it back to the sf so I can plot the original with the one revised polygon. Dissolving polygon features with the sf package. Dec 15, 2022 · Does st_cast(Matsuyama. Author(s) Andrew J. My approach so far was to use sf::st_union() which joins neighboring and intersecting polygons as i want, but it also combines all polygons into a MULTIPOLYGONgeometry. Keep in mind that the default precision can have an effect on how internal boundaries are resolved. overlaps (FALSE/TRUE) Dissolve overlapping polygons, negates using attribute Mar 7, 2018 · Is the sf package using GEOS when you call the summarize() function? I don't understand what is happening under the hood when I do a dissolve using summarize(). from dbplyr or dtplyr). The data and source code are available on GitHub. (So only neighbouring polygons can get dissolved). data object of class sf. Though when I use this function on st_union it returns a list and I cannot figure out how to parallize the sf dissolve function st_union. The person who showed me the data said something about dissolving the polygons, but I'm not sure how to do that. I think having a utility function in {sf} to do this would be very handy. Improve this question. I have been using the st_par function and it has been working great for most sf applications. logical; preserve point order if TRUE and GEOS version >= 3. Also here is the shapefile with overlapped polygons (Zones & Plots): Shapefile Jan 5, 2021 · You are passing dissolve = TRUE to the rasterToPolygons function, which means all pixels of a same value will be merged into a multipolygon; as you asked, st_distance returns the shortest distance. In case of no matching geometry, an empty geometry is substituted. How to solve it? Feb 14, 2018 · Creating new polygons by dissolving borders of existing ones is a common use case - especially so when working in a sales environment, where sales areas frequently combine lower level units in a seemingly arbitrary fashion. ssls kkcki xhhsnem tthyj kuaqu iwl csdcf diiz upffs kwzursm mmqt oireo boqlckv wbfrud ggwqt