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Questions tagged [smoothing]

smoothing is a generalization process that can remove any extreme values in a linestring or surface or just smoothens a linestring or polygon boundary by adjusting their vertex positions

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Smoothed landsat LST time series with lineair regression function

I am trying to get a smoothed result in GEE from my LST time series but I get an error that the memory limit is exceeded. How can I make my model more effective? This is my code: var LLST = require('...
Eppez's user avatar
  • 1
2 votes
1 answer
72 views

Incorrect output when smoothing line that intersects multiline with PyQGIS

I wrote a such script to smooth my line. It checks whether a line of two points intersects the border of a polygon and, if not, then draws a line. This script works well for a simple example, but bad ...
redhat's user avatar
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0 answers
58 views

Applying a Savitzky-Golay filter using OEEL with Google API

I've been writing a code based on instructions from Geo for Good 2022: Time Series Processing Using Google Earth Engine- https://www.youtube.com/watch?v=ncb5_zbvnaU. Specifically, after creating a ...
Mike Baars's user avatar
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0 answers
53 views

Breakline for contour

I am trying to generate a break line for generating contour. I have surveyed point data. I am using the river banks/HFl points as breakines. I created a new shape file and drew line along the HFl ...
Usha's user avatar
  • 147
3 votes
1 answer
178 views

Generating DEM that gives realistic contour

I am quite new QGIS user. I have point data from the field and I generated DEM and contour. However, the contours are a bit unrealistic. I have attached the image. The green contour is the contour ...
Usha's user avatar
  • 147
0 votes
1 answer
30 views

Multiple Points showing up for for a given date after applying a Savitzky–Golay filter to smooth my data

I've been trying to draw NIR and NDVI data from LANDSAT and SENTINEL-1 data respectively, which can often be a little noisy. As such, I've been trying to apply the Savitzky–Golay filter available at: ...
user231178's user avatar
4 votes
2 answers
439 views

Smoothing corners in polyline using PyQGIS

I have an array of QgsPointXY that makes a line with lots of vertices. How can I round the corners? Here is what I mean: The code is: def __round(line: list[QgsPoint], radius: float) -> ...
Alexander Petrushyn's user avatar
1 vote
0 answers
44 views

Why my NDVI animation using GEE is strange

I would like to show an NDVI animation of some Amazon area to demonstrate the deforest effects. Here is my high-level code. Get the NDVI from MODIS data and only use the images from Sept and December ...
bella's user avatar
  • 11
5 votes
4 answers
678 views

Smoothing round border of created buffer in QGIS

I have created a buffer out of point values with a fixed buffer zone of 150m. I would like to make the buffer look more naturally. I would accept an error margin of +/- 20 meters to flatten the curves ...
Cristian's user avatar
4 votes
1 answer
287 views

Vector smooth algorithm in QGIS has sharp corners

I am using the smooth function in a shape generator to represent tree canopies following this example It mostly works really well but I always get one sharp corner and its always at the second vertex. ...
Sethinacan's user avatar
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3 votes
0 answers
203 views

Smoothing of shared edges as result of Raster to Polygons/Contour to Polygon Tool

Based on a 15m DEM, I have created a Slope Raster, converted to polygons, calculated the slope bands and assigned a value, dissolved based on this value field and now I want to smooth the shared edges ...
Brent Robertson's user avatar
0 votes
1 answer
388 views

Comparing smoothing algorithms in R

I am comparing smoothing algorithms in R. More specifically, the raster.gaussian.smooth from the spatialEco package and the focal from the terra package. Visually, the results look similar but the ...
Nikos's user avatar
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1 vote
0 answers
109 views

Smoothing a DEM with visible grid

I have a DEM (1x1m) whose hillshade shows like this: As you can see, a grid shows up and that could be a problem for hydrological modeling. Do you know why this happens? How can I remove this grid ...
Luca IERVOLINO's user avatar
0 votes
1 answer
354 views

How to blur Landsat 8 image using a gaussian smooth filter with specified sigma value before downloading using Google Earth Engine?

I would like to add gaussian blur with sigma = 'some value' to Landsat 8 images before I download them using Google Earth Engine (GEE). So far I managed to simple download the images without adding ...
Nikos's user avatar
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0 votes
1 answer
153 views

Computed values outside of expected range (Earth Engine)

I'm working with an NDVI (normalized difference vegetation index) time series. NDVI is expected to have a range [-1, 1]. My analysis, which applies a Whittaker Smoothing algorithm, is producing values ...
Ruby's user avatar
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1 vote
0 answers
163 views

QGIS: Heatmap of polutant data using contour polygons

1. ASSIGNMENT I have got an even grid of points (figure 1) with attributes of the values of emissions or pollutants caused by traffic - modelled in a specialised SW for this. I need to use this point ...
Roman Dostál's user avatar
1 vote
1 answer
108 views

Sun's Mesh Denoise algorithm not working (feature preserving smoothing)

I tried to use Sun's denoise algorithm for elevation data via the RCP project from Jake but I cannot observe any changes to the TIF file: python raster_chunk_processing.py -m mdenoise -t 0.9 -n 10 -v ...
Karussell's user avatar
  • 707
2 votes
0 answers
95 views

Bringing river bed to the same height as surrounding ground in QGIS

I have a DEM containing the current flow networks in an area. I also have a shapefile showing the same flow network. I would like to derive a new river network to see how water would flow if the ...
Sofia's user avatar
  • 21
5 votes
4 answers
1k views

Smoothing out lines created by raster layers

I have a line layer that has been formed from a raster layer (It was a skeletonised raster layer). It now has a lot of unwanted vertices and needs smoothing out before further analysis. I have tried ...
Melanie Baker's user avatar
1 vote
0 answers
288 views

Smoothing/interpolating NDVI to remove missing data and outliers

I want to get the smooth NDVI data and want to remove the outliers, I want to know how can I achieve it. I attach my code, I tried to smooth it with 16 days window, but it still seems to have a sudden ...
Eva's user avatar
  • 75
2 votes
0 answers
115 views

Contour Polygon Alternatives on QGIS

I am trying various ways to make polygons from raster data using 1 m DEMs. I am using QGIS 3.16 Hannover I have tried vectorizing my data, which does work OK, but I would like smoother boundary lines ...
Erioderma's user avatar
  • 535
1 vote
0 answers
263 views

No difference between Savitzky-Golay 2nd order and 3rd order polynomial curve

I don't understand why there is no difference between Savitzky-Golay 2nd order and 3rd order polynomial curve? Perhaps the 3rd order polynomial curve is overfitted, not sure but the concern is yet not ...
ASHIS SARKAR's user avatar
2 votes
1 answer
183 views

Removing sharp curves using ArcPy

I have been trying for some time to find a way to eliminate the exaggerated curves in a contour curve that I usually obtain from line 0. The idea is to obtain a polyline that is more or less faithful ...
pyGisServer's user avatar
1 vote
0 answers
165 views

How to use a temperature raster (e.g., PRISM) to constrain temperature values in a thin plate spline regression and interpolation

I have point data with temperature, latitude, longitude, and elevation. I am interpolating across space to the extent of those points, and have been using elevation as a covariate in the fields::Tps. ...
AndrewGB's user avatar
  • 115
2 votes
1 answer
1k views

How to smooth the DTM?

I had a point file of an area around 70 km^2 collected through field survey using Auto Level. The survey was carried out in the lines 25 m apart. I converted the readings from auto level into point ...
Karan Gupta's user avatar
1 vote
1 answer
103 views

Orfeo Toolbox output rasters are 300x larger than inputs of the same size

I am trying to use Orfeo Toolbox CLI to do some processing, e.g. Smoothing: otbcli_Smoothing -in path/to/mosaic.tif -out output/smoothing.tif uint8 -type mean For now, the input, mosaic.tif, is just ...
Jan Pisl's user avatar
  • 726
1 vote
2 answers
295 views

Interpolate a new 3D surface between two other 3D surfaces

I have two 3D Raster surfaces which are flood height surfaces for two different flood heights. They each have XYZ coordinates. I now wish to generate a third surface BETWEEN these two surfaces at ...
Fred Spain's user avatar
1 vote
1 answer
564 views

Resolving trade off between smoothing via polynomial fitting and simplify-like algorithms (do not eliminate vertices)

I am struggling for a few weeks to use Python to smooth various linestrings and bumped into a conundrum. There seems to be a trade-off between using techniques that apply parametric curve fitting and ...
Julianno Sambatti's user avatar
2 votes
1 answer
455 views

Editing existing polygon vertices to create smooth curves using ArcMap

I'm editing a really detailed polygon in ArcMap. The vertexes of the polygon are connected with an straight line. I want to convert them in a smooth curve. While creating the polygon I use the "...
Matt_Geo's user avatar
  • 1,050
2 votes
1 answer
327 views

Smoothing all the intersection for GPX track points?

I have a.GPX Track file that has too many intersections. I want to smooth out due to all the intersection Currently, I'm trying to figure out a way to smooth out this track file. The intersections are ...
Noah Robison's user avatar
3 votes
1 answer
719 views

Creating a heatmap from TIFF file in QGIS

The task which I am currently working on, has us to create a kind of a 'heatmap' with KDE (or similar). As a first step I vectorized the TIFF File and now it looks like this: The end product should ...
Fabian Green's user avatar
3 votes
1 answer
229 views

How to get a smooth transition between startpoint and endpoint of a line in QGIS?

I have a layer with a few lines. They look very smooth in general, but there is a sharp edge at the start/endpoint of the line. Hot to eliminate that and get the blue dotted result line there?
POGO's user avatar
  • 294
0 votes
1 answer
287 views

Smoothing spline/raster in ArcGIS

I have a spline, but it turned out to be angular at the ends, is there a tool or how can I smooth the raster in ArcGIS?
easyfreeze's user avatar
0 votes
0 answers
56 views

How to smooth interior polygons of one shapefile

I have a shapefile that includes the boundary of a field plus many interior polygons that represent levels of NDVI - we'll say High, Medium, and Low. The larger areas have jagged, irregular edges. ...
hawkman's user avatar
1 vote
0 answers
303 views

How to smooth discrete raster data with GDAL in C++?

I am using GDAL in C++ for upsampling land-cover raster data. When upsampling, I would like to smooth out the edges, so that I do not get aliased stairs but nice diagonal lines. Essentially, the "...
kb173's user avatar
  • 11
3 votes
0 answers
81 views

Turn disjoint polygons into tessellation

I have a set of points that have labels. These labels represent geographies; however, some of the labels are wrong. Like in the picture below So after running some analysis, I end up with a set of ...
pbordeaux's user avatar
  • 131
2 votes
0 answers
595 views

Smooth contour lines/correctly extract contour lines from a DEM in QGIS

I have a DEM obtained as a result of the interpolation of elevation points TIN Interpolatin: I extracted the contour lines in QGIS and the result is this: After I tried to apply the Line Smoothing ...
ddomizia's user avatar
  • 648
3 votes
1 answer
212 views

A simple way to merge lines separated by a space in QGIS

In QGIS after creating contour lines by extracting them from a DEM (Extraction > Contour) and smoothing them (Line Smoothing) I noticed this situation: In order to smooth out the corners ...
ddomizia's user avatar
  • 648
1 vote
0 answers
327 views

Which resolution is appropriate for resampling a raster in a specific CRS in QGIS 3.6? [closed]

I'm trying to resample a raster file to obtain smooth interpolated levels in EPSG:3120 - Pulkovo 1942(58) / Poland zone I projection. (following the steps in this answer) 1. Using the raster ...
Iven Pepa's user avatar
  • 341
6 votes
2 answers
5k views

Making elevation contours of raster smoother using QGIS

I am using QGIS 3.6. I have raster of Europe map which I want to make a colored relief model. After duplicating the layer, used hillshade on backward layer and colored the upper layer interpolation >...
Iven Pepa's user avatar
  • 341
1 vote
1 answer
60 views

Seeking algorithm that can re-locate vertices on linestring so that line does not intersect land polygons

I'm currently working with GPS data gathered from boats. The data has low temporal resolution (every 5 minutes) which causes the linestrings that display the boat's trajectory to be jagged. An example ...
Devin Simmons's user avatar
1 vote
1 answer
245 views

Setting correct start and end time series for Savitzky-Golay in R

I am trying to smoothen my raster stack using Savitzky-Golay method. I am following the workaround from HERE but my problem is setting start and end of my time-series raster. My series of images were ...
mand3rd's user avatar
  • 161
0 votes
2 answers
485 views

Raster smoothing - assigning each raster the average value of its neighbors

I have a raster world map of population densities at a resolution of 30 arc seconds. For each raster, I want to find out the average density of neighbors within a certain distance (e.g. 0.1 degrees). ...
philsch's user avatar
  • 337
2 votes
1 answer
481 views

How can I smooth LineString coordinates with 1D Gaussian Filter?

I'm trying to smooth a LineString through 1D Gaussian Smoothing and I'm having a doubt on the steps required to implement it, regardless of programming language. I couldn't find by myself anything ...
RandomGISUser's user avatar
2 votes
1 answer
3k 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?
user143448's user avatar
2 votes
0 answers
173 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 ...
Majid's user avatar
  • 145
3 votes
1 answer
97 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 ...
Khorom's user avatar
  • 33
2 votes
1 answer
945 views

Blurring raster data across tile boundaries?

I have a raster dataset that is made up of 280 tiles, 51Gb total. I need to smooth/blur the data, retaining the same resolution. I would like to blur across tile boundaries, where possible, so that ...
naught101's user avatar
  • 496
2 votes
1 answer
5k views

GEE - Using Savitzky-Golay filter over an Image Collection [closed]

I'm trying to generate a smoothed MODIS(MOD11A2) time series by using the Savitzky-Golay filter. There is this github repo https://github.com/Fernerkundung/EarthEngine_scripts/blob/master/...
Inacio Bueno's user avatar
1 vote
1 answer
65 views

How to apply smoothing filter only to way bigger than specified number of nodes, length, area?

I am try to smooth data obtained by vectorization of a raster image by applying a series of filters in GRASS GIS. Once of steps involves using the Douglas-Peucker filter. However, I need to apply it ...
Grigory Rechistov's user avatar