Questions tagged [smoothing]

smoothing is a generalization process that removes any extreme values in a line string or surface

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52
votes
3answers
17k views

Smoothing polygons in contour map?

Here is a contour map for which all the polygons of levels are available. Let ask how to smooth the polygons keeping all vertices preserved in their exact locations? Indeed the contour is made on ...
45
votes
5answers
33k views

What raster smoothing/generalization tools are available?

I have a DEM that I would like to smooth or generalize to remove topographic extremes (chop off peaks and fill-in valleys). Ideally, I would also like to have control over the radius or level of "...
37
votes
5answers
50k views

Smoothing/generalizing polygon in QGIS?

Is it possible to smooth or generalize a polygon in QGIS, perhaps by using a plugin like the generalizer-plugin for lines? I could convert my polygons to lines, smooth them and convert them back to ...
22
votes
3answers
10k views

Performing Raster Noise Reduction and Edge Smoothing?

I have a raster image like this I want to delete the isolated noise point and smooth the edge (say the white single points, and I want the edges of the entity look smooth). How can I do this in ...
10
votes
2answers
357 views

Make several rasters more uniform

I have imported some rasters that is supposed to be continuously connected but instead they create some sort of bordered grid between them. I may assume that this is a matter of calibration between ...
9
votes
2answers
1k views

How to smooth adjacent polygons?

I want to smooth polygons which share a common boundary. How can I smooth them so that the shared boundaries stay shared? I'm using Arcgis 10.3
9
votes
3answers
3k views

How to perform SIA or Bezier line smoothing in PostGIS?

Can anyone provide an example SQL for smoothing linestrings from postgis table using Bezier curves or Iterative Averaging (SIA) algorithm?
8
votes
1answer
507 views

Raster smoothing

I am an italian student. I'm using ArcMap 10. For my thesis I need to simulate a debris avalanche, but in my elevation raster the avalanche deposit is included so I'd need to take it off to simulate ...
7
votes
2answers
598 views

LiDAR intensity image from multiple flight lines?

I'm working with multiple raw las tiles, and I've used Fusion to create an intensity image, but it shows the flight line overlap (see below). Any idea how can I smooth the image so that the overlap is ...
7
votes
1answer
1k views

Free implementation of Polynomial Approximation with Exponential Kernel (PAEK) algorithm

I need a Free (i.e. Open Source) implementation of the Polynomial Approximation with Exponential Kernel (PAEK) algorithm, preferably in C, C++, Python, Julia or R. The algorithm is one of the ...
6
votes
3answers
807 views

Smoothing method for big polygons

I'm looking for an alternative to 'snakes method' for smoothing very big polygons, which I created from SRTM elevation datasets. The problem is that the smoothing is getting stuck after a while with ...
6
votes
1answer
2k views

How do I smooth edges of polygons in QGIS?

Is there a built in function or plugin I can use to achieve smooth lines for my polygons instead of the blocky ones I have now?
6
votes
1answer
2k views

Smooth, not simplify, lines features in PostGIS

I'm trying to automatically generate paths to place labels on that follow the shape of rivers, 4wd tracks and other very windy lines. At first I thought the st_simplify() function was the answer, but ...
6
votes
1answer
568 views

How to build Poisson autoregression model

I have a SpatialPolygonsDataFrame object in R with about 3000 polygons and associated data. I have columns of expected and observed cases. For the moment, I don't have any covariates. I'd like to ...
5
votes
1answer
3k views

Smoothing of a DEM

I have a DEM which has some individual pixels lower than those around them. This is a problem as I am using the DEM for pluvial flood modelling and therefore it is providing an incorrect ...
5
votes
1answer
2k views

How to reproduce Smoothing from Generalizer Plugin in v.generalizer in Processing Toolbar using QGIS?

I´d like to reproduce the smoothing operations done with the Generalizer Plugin inside the v.generalizer Toolbox so I can use them on a polygon layer instead of only on a line layer. I tried ...
5
votes
1answer
340 views

Smoothen Line vector QGIS

I am working on a publication and would like to make my schematic visually pleasing. The amount of detail is too high and the image would be better If I could simplify and smooth my line and polygon ...
5
votes
1answer
464 views

Snap existing line vertexes to nearest line in MapInfo

I have driven along some roads and registered some information about the state of the edge of the road. The GPS coordinates are not very precise, and I would like to smooth or snap the tracked lines ...
4
votes
1answer
503 views

Vector to Raster for Smoothing purposes using ArcGIS Desktop?

I have a vector file that represents transit scores by Census Tract (CT) of a city. It shows harsh boundaries where one CT has great access to transit and right beside that CT is one that has ...
4
votes
1answer
3k views

QGIS Raster map, smoothing pixels

I am trying to generate a map in Qgis which makes it possible to see the temperature of a region during a heatwave. This was a great succes. However, I want to add shades as well, since shades lower ...
4
votes
1answer
647 views

Polygon inner rings/holes issue

I am working on a script to smooth polygons. Essentially it, separates the inner and outer rings/polygons and send the coordinates to a smoothing def/function. The "smoothed" coordinates are then ...
3
votes
1answer
5k views

Smoothing raster map using R?

I am trying to create a map from raster data. The file came from a crop model, with resolution of 0.5 degree. Even when I disaggregate it (i.e. increase spatial resolution), the map looks really ...
3
votes
3answers
171 views

Smoothing raster with binary cell values

Main question towards the end. Details follow now: I have a slope raster Region: Bern, Switzerland CRS: EPSG:2056 - CH1903+ / LV95 - Projected Extent: 2587757,...
3
votes
1answer
203 views

Methods behind qgis:simplifygeometries and qgis:smoothgeometry?

I would like to know on which method (e.g. Douglas-Peucker line simplification) the modules qgis:simplifygeometries and qgis:smoothgeometry are built on. I cannot find further information on these ...
3
votes
1answer
2k views

How to smooth NDVI raster (Sentinel 2-A image) in ArcGis?

My question is regarding the final display of a NDVI raster. I currently work with ArcGIS Desktop 10.2.2. When I work with Landsat images (the image is loaded as composition through the MTL file, ...
3
votes
2answers
694 views

How to generate Non-smooth/crude Contour Lines in QGIS?

I have an SRTM DEM and I want contour lines generated for specific elevations. This can easily be done using r.contour.level/step etc. but the contours generated are smooth and cover the cells only ...
3
votes
1answer
39 views

Exporting render of polygon after applying smooth geometry command using QGIS?

I have recently discovered the smooth($geometry,x) command in QGIS which is very convenient for me. However, when exporting polygons, the "smoothness" obviously goes away as the vertices are untouched ...
3
votes
1answer
3k views

problem with polygon smoothing in R

With R I am looking to smooth my Polygon: inter2.csv code: inter1 <- read.table("c:/inter2.csv", header=TRUE) # add a category (required for later rasterizing/polygonizing) inter1 <- cbind(...
3
votes
0answers
131 views

Why do I get invalid elements (polygons), when smoothing a vector layer (smooth geometry)?

The problem occurs, when using the commands "Smooth geometry" or "v.generalize.smooth" in QGIS. The shapefile, which I want to smooth, shows a flood water level and looks like this: The water level ...
3
votes
0answers
232 views

gdal_grid invdistnn with smoothing?

I am trying to generate a raster with many pixels (10240x10240) using the gdal_grid tool but I have problems choosing the right interpolation algorithm. I have a dataset with varying point density (...
3
votes
0answers
83 views

Blend overlapping DEMs using Open Source / Python

I'd like to blend edges of overlapping DEMs such that the join is a smooth transition (for use with InSAR). Apparently the best interpolation kernel for this, according to the literature, is thin ...
3
votes
0answers
1k views

Smoothing Lines in PostGIS

I want to smooth Lines in postgis, to be more specific, I want to smooth road data from OpenStreetMap. Basicly I thought of something like this scenario. This would be a possible road segment. I ...
2
votes
1answer
712 views

Using Chaiken Method parameters for smoothing polygon vectors in QGIS [duplicate]

I've been trying to smooth a huge polygon, that is result of a segmentation export. I'd like to know what's the best parameters to use Chaiken Method to get smooth curved boundaries on QGIS 2.14. I ...
2
votes
1answer
67 views

Smoothing polygons in QGIS? [duplicate]

I vectorised an image and all my polygons have extremely jagged edges. What is the best way to smooth these polygons?
2
votes
1answer
743 views

SAGA Gaussian filter lower value than 1?

I'm smoothing a 2 meter DEM using the Gaussian filter in SAGA through QGIS/Processing and the smallest amount for the smoothing of the Standard Deviation value of 1 which for me is too much, it all ...
2
votes
1answer
2k views

From trajectory of GPS points to multiline segment?

Given a trajectory as a sequence of GPS points I would like to create a smooth linestring representing a path where a car drove. The data is stored in postgresql: the input trajectory in a table, ...
2
votes
1answer
386 views

Data smoothing of Sentinel-2 NDVI time series chart in Google Earth Engine?

I am exploring Sentinel-2 time-series NDVI with Google Earth Engine. In another post I learned how to plot a NDVI time series chart. I know that there are many smoothing methods for reducing NDVI ...
2
votes
0answers
32 views

Smoothing MODIS LAI? [closed]

I am trying to smooth 8 days LAI data from MODIS and managed to work around it with several algorithms such as loess, Savitzky–Golay, smooth.spline etc. This is pretty much going well if the level of ...
2
votes
0answers
51 views

World DEM speckled outcome solution

I have a world digital elevation model which has been classified into 5 showing the different heights. My issue is that viewing and printing this image as it is results in a speckled look due to the ...
2
votes
0answers
136 views

Optimized smoothing of stream lines generated from Arc Hydro? [closed]

Has anyone found an effective ArcGIS 10.3.1 workflow for smoothing streamlines generated from ArcHydro...or hydrology in general? (Fill -> Flow Dir. -> Flow Acc. -> Stream Def. -> Stream Seg.-> ...
2
votes
0answers
186 views

Smoothing borders of polygons taking a layer of points into account

I'm trying to smooth borders that separate clusters of points. GRASS instrument v.generalize.smooth works pretty well, except that in some cases the points end up on the wrong side of the smoothed ...
2
votes
0answers
75 views

Smoothing out polygons without gaps? [duplicate]

I'm converting a raster data to vector data. The problem is similar to this: How to smooth large vector polygons from Raster But what I need to know is how can I handle out the gaps that are formed ...
2
votes
0answers
586 views

Leaflet: Smooth lines between points without control points? [closed]

Goal I want to connect points using a polycurve or curved lines in Leaflet in a scalable way. If possible, without defining control points. Approach I'm using the Leaflet.curve plugin which offers ...
2
votes
1answer
76 views

Gap filling for linear features using ArcGIS Desktop?

I have a Landsat time series from which I derived NBR using bands 4 and 7, and delta NBR (to show changes). I then set a threshold based on the mean and standard deviation delta NBR values to ...
1
vote
1answer
713 views

Smooth linestring shapefile

Is there an algorithm to perform a smoothing of a linestring and maintain the original points?
1
vote
1answer
1k views

Raster time series smoothing package using R

Does somebody knows if exist a package in R specifically for raster time series smoothing? I´m using aproachs like this one (using the equation suggested by Hamunyella et al., 2013) for (i in 2:(...
1
vote
1answer
243 views

Raster data like heatmap from polygons w.r.t their own values

I have polygons as below, and each polygon is assigned to some value. What I'd like to do are ... Smoothen boundaries (Values should change more smoothly around boundaries) Fill N/A part properly ...
1
vote
1answer
867 views

Looking for a tool to smooth edges of raster areas in QGIS

I am looking for a tool which helps me to smooth primarily edges/outgrowths of raster areas/zones in QGIS/GRASS/SAGA. I particular, regarding the image below, I would like to reduce the single lines (...
1
vote
1answer
78 views

Generalizing slope raster in Mapinfo?

I am working on calculating a slope raster in Mapinfo using a 15cm DEM derived from a LiDAR point cloud and the output data will have 3 predefined breaks displayed so I need to blur those relatively ...
1
vote
1answer
49 views

Remove small interstices on the edges of a polygone

How can I remove the white interstices on the edges (and interior) of a polygone or polyline, as represented in the first figure below? I want to get smooth and continuous edges, capturing the global ...