Questions tagged [smoothing]

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

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2
votes
1answer
952 views

Smooth linestring shapefile

Is there an algorithm to perform a smoothing of a linestring and maintain the original points?
3
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0answers
20 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 ...
2
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0answers
33 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 ...
4
votes
1answer
5k 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 ...
1
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1answer
32 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 ...
1
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0answers
54 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 ...
5
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2answers
242 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 >...
45
votes
5answers
35k 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 "...
0
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0answers
13 views

Impact of r.neighbor window size on raster values

I have the residuals of a detrended DEM of a glacier surface in QGIS. With these residuals I have used QGIS' r.neighbor standard deviation over a range of neighbourhood sizes (window sizes) as a proxy ...
1
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1answer
42 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 ...
0
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1answer
53 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). ...
2
votes
1answer
82 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 ...
1
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1answer
41 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 ...
5
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1answer
1k 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 ...
2
votes
0answers
764 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 ...
1
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0answers
82 views

Avoiding tiling/mosaicing in resulting image when Pan-sharpening Gram-Schmidt?

I mastered to georeference some declassified Hexagon satellite imagery from the 60s and would like to use it to pan sharpen a current Sentinel satellite image (already done as RGB). It is very ...
1
vote
1answer
117 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 ...
2
votes
1answer
416 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
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0answers
69 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 ...
3
votes
1answer
48 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 ...
1
vote
1answer
604 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/...
1
vote
1answer
33 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 ...
3
votes
0answers
281 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 (...
1
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0answers
280 views

Error with “lowess” function in R

I have a problem with lowess function to smooth NDVI as a time in R. Here is the scripts I run: #Create a time vector to act as x time<-sort(sample(97:297, nlayers(ndvi2000crop1))) #locally-...
0
votes
0answers
650 views

QGIS smooth raster DEM [duplicate]

Possible Duplicate: Raster generalization - buffers in rasters, expand pixels? I have a 1m LIDAR DEM which I'm manipulating in QGIS. I'd like to smooth the DEM, such as by having each pixel ...
2
votes
1answer
735 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 ...
3
votes
3answers
358 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,...
1
vote
1answer
37 views

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 ...
1
vote
1answer
94 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 ...
2
votes
0answers
57 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 ...
1
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0answers
63 views

Importing .geotiffs and wavelet denoise plug-in - GIMP

I am trying to run the wavelet denoise plug-in tool on GIMP to smooth a .geotiff. Unfortunately when I import the .tiff, the spatial refernece is lost and the image appears black. My goal was to ...
1
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0answers
39 views

Obtaining a smoothed DTM?

I am use AcGIS 10.1 and have a DTM with an 8 m grid resolution. Which tool could I apply to smooth the surface?
1
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0answers
25 views

Smooth Data Values Across Geographies with Zero Population

Looking to fill in gaps through generalizing a population count across U.S. counties. I.e., if a county has 0 population, but is surrounded by 5 non-zero counties, then change the 0-population county ...
1
vote
1answer
54 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 ...
7
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 ...
1
vote
1answer
1k views

Continuous smoothing of raster using R?

I have a dataset on some villages like this on a grid: I want to fill the space of the whole grid so that each grid cell has a value that reflects the pressure from the surrounding villages (i.e., ...
2
votes
0answers
241 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
193 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 ...
52
votes
3answers
19k 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 ...
40
votes
5answers
56k 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 ...
3
votes
0answers
149 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 ...
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
5
votes
1answer
590 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 ...
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 ...
1
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0answers
252 views

GRASS r.denoise error

I have installed r.denoise, put mdenoise into QGIS2.18/bin and installed "pip install pyproj". However when I try to run r.denoise on STRM DEM, a get this error: ERROR: Unable to open file <...
3
votes
1answer
6k 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 ...
2
votes
0answers
115 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 ...
3
votes
1answer
272 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 ...
1
vote
0answers
60 views

Rule of Thumb for setting smoothing parameter

I'm trying to model some binary data (disease infections) using indicator kriging in the Geostatistical Wizard in Arc 10.3. For presentation purposes I'm using the smoothing option. Is there a rule of ...
0
votes
2answers
8k views

Using raster to clip vector data

I have high res raster data covering 2million km sq, with a field where each cell has a value from 0 to 100. I need to create a "mask" using the cells with a value over 12 in that field. I then need ...