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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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:
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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) -> ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 "...
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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 ...
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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 ...
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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?
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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?
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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. ...
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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 "...
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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 ...
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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 ...
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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 ...
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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 ...
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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 >...
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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 ...
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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 ...
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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). ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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/...
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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 ...
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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 ...
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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 ...
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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,...
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Mapnik upsampled raster isn't smooth
I'm using Mapnik to show a map with hillshading. It works well when displaying it up to my tiff's native resolution and a little bit above, for instance at zoom 13 (dataset is SRTM30):
But then if I ...
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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 ...
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