Questions tagged [interpolation]

The estimation of values at unsampled points based on known values of surrounding points.

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Clipping interpolation layer to a coastal boundary in QGIS 3.6?

I have created an interpolation layer and want to clip it so I don't see the area outside the coastal boundary. map showing area to be clipped:
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22 views

Resampling while drawing rasterfiles in QGIS 3?

I can not find a solution to resample my rasterfiles in QGIS 3. With Arcmap usually I use "resample while drawing" with the method cubic or bilinear interpolation for continuous data to smooth my ...
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Multiply two image collections with different sizes based on dates

I have two image collections. They are both filtered by date beginning on Jan 1, 2019, and ending on today's date. The size of the first (kc) is 35 images and the second (ETo) is 225. The first has an ...
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1answer
47 views

Creating rasters from LiDAR using parameters other than elevation, intensity or class?

There are a number of tools out there that can create a raster from a LiDAR point cloud by interpolating elevation, intensity or class values, but these tools generally limit you to interpolating ...
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38 views

IDW interpolation using QGIS?

I want to obtain the quantity of precipitation for each municipality in Brazil on a given year. For that, I'm trying to use IDW interpolation on QGIS to interpolate the precipitation data from weather ...
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1answer
21 views

What are the formulas used in SAGA Ordinary Kriging?

can some one name the formulas avaible in the Ordinary Kriging Modul of SAGA: What ist the exponential, spherical, Gaussian-Model, etc.?
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22 views

Speed- and COG-aware trajectory interpolation/resampling using Python

I have a set of ship trajectory points that were irregularly sampled and I would like to resample them to a fixed frequency (e.g. every minute). Rather than just linearly interpolating between ...
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28 views

ArcMap: interpolation for single polygons individually

The red polygons in the image represent the boundary of infills. The raster (colored area) within the polygons is interpolated from the point shape file (black dots). The image shows an example where ...
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1answer
79 views

R kriging raster returns NA for some prediction points?

I am trying to interpolate a raster layer of chlorophyll-a data using kriging (gstat::krige) in R, however the resulting interpolation is showing NA values in a peculiar straight line through the ...
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25 views

Multi-variate hotspot mapping in ArcGIS

I'm looking to create a map similar to the one below--essentially an interpolated map, but using multiple categorical variables. Has anyone seen an application of interpolation that can do this in ...
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48 views

Performing interpolation with QGIS in Python application?

I have to make an interpolation map for river water quality, but it must be made in the Python programming language. Can I use QGIS in a Python application? Not Python in QGIS but QGIS in Python.
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Is there a way to interpolate lost data/lost pixels caused by cloud and cloud shadow masks in Google Earth Engine? [duplicate]

I'm sure cloud and cloud shadows have been, time and time again, a frustrating problem. Usually after masking the two, I composite multiple images (in a set time interval e.g. 2015-2016, months 6-8) ...
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1answer
61 views

How to use a regression equation to create a map in QGIS?

I have been working on creating an exposure map based on measures taken at fixed points. I want to extrapolate the results to a grid to get an exposure map (air pollution data) for a region based on ...
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1answer
74 views

Interpolation using QGIS?

I want to do cubic spline interpolation with QGIS (3.6), but: Why the result of interpolation is not a polygon? And interpolation don't cover all country? (see attached picture)?
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1answer
35 views

Normalized interpolation doesn't work for WGS84

I am trying to interpolate linestring on WGS84 coordinate system by factor 0.5. LineString length is 427 meters (measured by different tools), so I expect to get line with length=213.5 meters. But I ...
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1answer
78 views

Smoothing/interpolating across images in an ImageCollection to remove missing data

I have some code that is working properly to calculate the monthly NDVI averages for the previous two years from a date but I sometimes have missing data in some of the months and I would like to get ...
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36 views

Getting AttributeError: 'NoneType' object has no attribute 'sourceCrs' from TIN Interpolation in QGIS?

I am trying to use the TIN interpolation to interpolate conductivities between a vector layer in QGIS 3.4. and I always get this error: Traceback (most recent call last): File "C:/PROGRA~1/QGIS3~1.4/...
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44 views

qgis Error: Column type not supported using v.surf.idw

I have counts data from aerial measurements that I am trying to make an interpolation map from using Q.GIS 2.18.14. I have done a tutorial first with test data, then compared the test data to my data ...
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21 views

Interpolating timestamps for breakpoints for linestrings of GeoJSON

I have a GeoJSON file containing a couple of LineStrings. The properties contain the Departure and Arrival timestamp for each LineString. I would like to interpolate the timestamps for each breakpoint ...
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33 views

Overcoming spatial bias in ArcMap or ArcGIS Pro?

I have a shapefile showing invasive plant locations but they mostly collected from more accessible places such as near roads or hiking trails. Is there a method to correct this bias in ArcGIS ...
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1answer
22 views

Running IDW, but values are '<1' not 0.934 so they are Strings not Doubles

I am trying to use some interpolation tools for analytical data of concentrations of Benzene for monitoring wells. A decent amount of our values for Benzene are '<1' (not 0.943 or 0.345) because of ...
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1answer
155 views

R - IDW interpolation using gstat

It contains two coordinate columns dist for distance in x direction and rel_alt for an altitude in y direction. The other two columns are the data points for each combination of those two coordinate ...
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Using convex hull for interpolation of individual plots or lump plots together in ArcMap?

This question is inspired by Using kriging to extrapolate values outside of sampling polygon in ArcMap? I'm working on a project trying to understand the lasting effects of historic scientific ...
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Interpolating sea level data using ArcGIS Desktop?

I have monthly sea level data obtained from PSMSL in the form of excel sheet for the region Chennai. I want to interpolate the data in ArcGIS Desktop. The shapefile of the region has Polygons and I ...
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15 views

GRASS GIS - V.VOL.RST avoid segmentation (paneling)

In order to reduce the segmentation effect where the interpolation appears to have different square regions, is this due to segment that are too small (segmax?). Is the solution to avoid this to ...
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1answer
189 views

IDW interpolation in Python in QGIS 3.4

I have a problem with IDW interpolation. I need to use canvas extent and other attributes (I created an option with only attribute 0, other attributes aren't working). The documentation is not very ...
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2answers
38 views

Calculate raster statistics for polygons in a polygon feature class

I have a DEM across my study area where symbology has been changed to show elevation changes in 100m intervals. I have a polygon feature class where each polygon delineates a landslide. My landslide ...
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27 views

QGIS crashes instantly with multilevel B-Spline tool

I'm trying to use the multilevel B-Spline tool by SAGA in order to interpolate some points and create a raster image. But sadly while the process is running, QGIS crashed without any error message. ...
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1answer
106 views

Interpolation of 3 borehole data

I have three points (boreholes) on the map. I created them using shape file layer. Each borehole shape file layer shows the strati-graphic section of the ground. (i.e. between 0-50 m = Gravel , 50-60 ...
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1answer
88 views

How to generate triangulation file via QGIS C++ API

I created a plugin few years ago in Python. The plugin uses QGIS interpolation and works for QGIS 2.18. But because the QGIS interpolation creates raster (grid) and I need only Triangulation (TIN as ...
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1answer
101 views

Interpolation of data points

I have a layer of points that represent bus stops. Each point has a value (quality of service, between 0 and 100). I need to create a grid (resolution 25m) by interpolating the points values. For ...
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1answer
70 views

Understanding spsample in R?

I have read the documentation for this but still unsure of what the function spsample does. The documentation is here: https://www.rdocumentation.org/packages/sp/versions/1.3-1/topics/spsample I ...
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Interpolate 3D raster with Anisotropy

I am building a 3D geological model for soil deposits. I have two approaches to build a 3D raster. My dataset is about 300k points of bh information with texture and permeability at every meter ...
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1answer
60 views

Unable to select interpolation attributes from my shapefile?

My point shapefile has four fields, three of which are numerical: longitude, latitude, and homicides. However, the homicides field does not appear for me to select it as an interpolation attribute (...
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1answer
47 views

Why is the ArcMap IDW tool interpolating values higher that it's closest data points

I have a dataset of equally spaced, by 3 arcseconds, points. Each point represents the radio signal strength from a near by transmitter. I wanted to convert the point data set into a raster for ...
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50 views

Automatic creation of polygons

How do you automatically create adjacent polygons in QGIS whose size depends on an attribute of another layer? I have a layer with community areas and the corresponding number of inhabitants and ...
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1answer
43 views

QGIS - 3D data set with stacked points at different elevations, is it possible to create data points at each elevation

I have a 3D dataset consisting of xyz and property. The data points are along vertical axis (boreholes), and at different XY locations (at other borehole location). The data points are not all at the ...
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2answers
199 views

How to use GDALGridInverseDistanceToAPower in a python script

I'm trying to use GDAL in a python script to do an inverse distance interpolation. Within the C documentation API I found GDALGridInverseDistanceToAPower function but I don't know how/if I can call ...
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69 views

Using spline / IDW interpolation for bathymetric profile of lake bed in ArcGIS Desktop?

I have partial bathymetric / topographic coverage at 1m resolution of a lake bed and shore and am trying to find an appropriate method for 'filling in the gaps'. I have tried using the following in ...
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1answer
187 views

Interpolate a Smooth Contour From Points

I have points scattered around some origin point, each with a score. The score should be zero at the origin (similar to distance). I want to generate smooth contour lines from these points. The red ...
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64 views

Importing several LiDAR (.las) files in GRASS using v.in.lidar?

I'm building a DEM of a terrain in GRASS and have 48 LiDAR (.las) files. I know I can do this by using r.in.lidar (including the list of files as a .txt) and then r.fillnulls However, I want to ...
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42 views

How to mask a raster layer (interpolated surface) onto a polygon layer? [duplicate]

I have performed interpolation (IDW) for average monthly precipitation and temperature values for Europe. For my project, I'm focusing on the UK and Sweden so I'm wondering can I clip or mask the ...
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2answers
30 views

Specifying which point buffers fall within a particualar land type (polygon)

I have a point buffer layer which represents tick occurrence and a polygon layer which represents landcover types (derived from Corine land cover). I want to define which point buffers (1km) fall ...
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23 views

How to create a surface layer from gridded point data of air temperature and Precipitation?

I want to aggregate monthly averages of temperature and precipitation over a 10-year period into weighted seasonal averages (DJF) for use in interpolation. I have downloaded Shapefiles for each month (...
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1answer
109 views

Cant find contour lines raster extraction

I am trying to create contour plot concentration data to a map. I followded this link and have interpolated the data as follows: but, while forming contour lines, I am not finding the raster> ...
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1answer
123 views

Interpolating LiDAR intensity images in R?

I'd like to generate 0.5 m intensity images using lidR, but the resulting raster is full of pits. Here's a reproducible example: library(lidR) LASfile <- system.file("extdata", "MixedConifer.laz", ...
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2answers
71 views

How to densify point feature class in ArcGIS?

I have a 3D (x,y,z) single point feature class which points are equally spaced, like this: As the distance between each points are more than one meter, I was wondering if there's a possibility to ...
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113 views

Problems with SAGA on QGIS

I'm trying to perform an interpolation on SAGA in QGIS but every time I ran the tool (or any other SAGA tool for that matter) I got the following message: "The following layers were not correctly ...
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1answer
52 views

Seeking ArcGIS TREND tool equivalent in R?

Arc features the TREND function with linear interpolation up to 12th order. Is there an equivalent approach in R (preferably) or python? I'm trying to de-trend a raster surface using polynomial ...
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1answer
44 views

Exporting string and float variables to ASCII file using ArcPy?

I am trying to create a script using arcpy to automate a serie of task in ArcGIS. What I am trying to do is to interpolate rainfall data from a region and then, using hydrological basinshapefiles, ...