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Questions tagged [inverse-distance-weighted]

Inverse Distance Weighting (IDW) is a method of interpolation.

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Creating IDW-rasters from each field in large point feature set using ArcPy for ArcGIS Pro? [closed]

I am using ArcGIS Pro 2.3.2 I am trying to automate the process of making a raster (IDW tool) in model builder by iterating through fields as z-value. I saw some other question asking the same, and ...
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1answer
20 views

Why is raster boundary rectangular, not buffer?

First, I took very few points and did IDW and i got a circular boundary raster. This is because of the search radius i applied. If that is the case, for large number of points, the raster must look ...
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1answer
24 views

How is IDW raster formed?

IDW algorithm says that it makes a grid and assigns value to each point in grid depending on the distance of separation. From this definition, it looks like the output is set of equally spaced points. ...
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1answer
52 views

QGIS 3.x contour creation tutorial

I'm trying to follow this tutorial so I have a method for creating contours in QGIS because I find the contours generated by the contour plugin a bit strange (very sharp edges and whatnot). I can't ...
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1answer
79 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
25 views

Default parameter values in r's gstat idw?

In r, gstat has an Inverse distance weighted (IDW) interpolation method. Does anyone know what the default values of nmin, nmax and maxdist are?
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2answers
288 views

Making data table using linear kriging interpolation with variogram in R

I have a table of data with such structure: longitude_for_data = c(32,68,89,145,176, -14, -42) latitude_for_data = c(22,98,21,13 , 16,-134,-102) Z_for_data = c(30,40,60,70 , 20, 40, 100)...
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1answer
24 views

Including buffer to IDW in ModelBuilder

I have created a model with ModelBuilder to interpolate values with the IDW tool, iterating through rows. How can I restrict interpolated values to regions within a 20km buffer? I tried setting the ...
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1answer
37 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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2answers
95 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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0answers
29 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
32 views

Improving IDW and Sample Model using ModelBuilder?

I want to create a dataset of estimated values using inverse distance weighting. I am starting with a dataset of daily values of measurements for specific coordinates. I created a model (below) which ...
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1answer
25 views

Building model to select values at point from folder of several raster layers?

I am using ModelBuilder to interpolate values with inverse distance weighting, iterated through several rows, resulting in many raster datasets - one raster layer per row. I have this and all the ...
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1answer
30 views

Finding creator of Inverse Distance Weighted method?

I am interested in the very first person who invented the Inverse Distance Weighted method or the very first reference that this method was mentioned. I tried to search on Google but could not get ...
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1answer
56 views

Using Row Iterator and IDW in ModelBuilder?

I am using ModelBuilder to perform inverse distance weighting. I would like to interpolate values using a point file with values for several unique dates - resulting in a raster dataset for each ...
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2answers
112 views

Understanding Inverse Distance Weighting Bulls Eye Effect?

Is the Bulls Eye Effect generally caused by a sample point with a high value being too far from other sample points? Or rather a sample point with a higher value than others close to it? What ...
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1answer
137 views

Kriging method vs. IDW in soil moisture interpolation

I have XY coordinates and soil moisture values for a grid of 10m and I used add XY data to import my excel data to ArcMap 10.5. I applied both IDW and kriging methods for interpolation. The results ...
2
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1answer
103 views

Expanding IDW interpolation to borders of country in ArcGIS Pro? [duplicate]

I am new to ArcGIS. I have a data set with air pollution concentrations for 20 locations in the Netherlands. I would like to interpolate this data with IDW, so that I can estimate the approximate ...
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1answer
79 views

IDW/Kriging running slow in R

I have a dataset with 2157335 entries, and I am performing IDW/Kriging to interpolate. But the code is running very slow. I am not sure this is because of a large dataset or there is something wrong ...
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23 views

Making error or confidence surface in ArcGIS Desktop?

I have a student working in my GIS lab who is computing an IDW interpolation surface for observations taken from a boat moving along a series of paths. The sampling paths were not uniform over the ...
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0answers
93 views

Interpolation in QGIS shows wrong output result [closed]

I have done interpolation (IDW and Nearest Neighbour) in QGIS. But interestingly the output shows the wrong result. The area where I have a huge number of points results in a lower Z value (it is ...
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1answer
157 views

IDW Interpolation pyqgis QGIS3

I try to create a interpolation with the follow script, the problem is that when the program tries to write QgsGridFileWriter, qgis crashes. The problem is that the different examples are to lower ...
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1answer
137 views

IDW with buffer in QGIS

I'm very new to QGIS and am having some issues using the SAGA IDW tool. I'm attempting to perform an interpolation using the 10 closest sample points and an inverse distance power of 2. I would like ...
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2answers
854 views

IDW Interpolation in QGIS [duplicate]

I'm using the Interpolation plug-in in QGIS 2.18 to perform IDW Interpolation. I was hoping to specify a power of 2 and use the 10 nearest points to calculate the output, but I don't necessarily see a ...
2
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1answer
94 views

Cannot add ArcGIS ModelBuilder output to table of contents

I've made a model that creates some points with Z value and a buffer, which I then do a 3D analyst IDW on, and a Cut Fill analysis. The model input is a line along with af DEM/Raster, and some names ...
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1answer
27 views

IDW possible to fill out buffer area?

I've got a lot of points with Z-values, where I would like to construct their extent using IDW (or similar). I would like to see their extent inside my buffer, is this possible or is the tool not ...
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2answers
314 views

Using buffer from IDW in ArcGIS 3D Analyst for flood spread?

I have a line in the centre of a road, with the roads elevation attached to its properties. By using Generate Point along lines --> Add Surface Information --> Adding 10 cm to that, and then IDW 3d ...
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1answer
106 views

Why v.surf.idw returns only two value (one is nan)

I am trying to perform a vector interpolation of a point shapefile with the intent of eventually creating a DEM. No matter what I try, I get only 2 values one of them is NAN, and nothing is working to ...
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1answer
145 views

Checking accuracy of IDW using ArcGIS Desktop?

I performed IDW using ArcGIS on 121 evenly distributed samples and generated a surface. How do I check the accuracy of the method?
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1answer
253 views

Extrapolating with IDW (Feature Classes) in ArcGIS Pro?

I have been struggling to extrapolate beyond the extent of the point features input into the IDW tool of ArcGIS Pro. I believe IDW interpolation is the method for me, i just need the process to ...
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2answers
373 views

How weights in Kriging are calculated, and predict beyond range of sample values?

In Esri's documentation on how to make a prediction in Kriging, I couldn't figure out the linkage between the semivariograms and the prediction process from reading the description therein: After ...
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1answer
49 views

point count from in Inverse Distance weighting procedure - QGIS

I have conducted an interpolation using IDW procedure. I have vectorized the interpolation in order to be able to specify a 3 class clasification. I have additional point dataset indicating the ...
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1answer
197 views

IDW Interpolation in QGIS gives weird values

I'm trying to do an IDW interpolation with QGIS tool. But i'm really surprised by results. Interpolation values aren't similar as shape values. I used a power of 0.2 to get a smooth raster. Somebody ...
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1answer
823 views

Create a rainfall raster with gstat or idw in R

I am a beginner in R, I need to use gstat or idw function to get a rainfall raster, but I have an error in the formula. How can I change it? This is my code: setwd("C:/Users/A/Desktop/...
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0answers
45 views

Constraining an IDW interpolation [closed]

I am running an IDW on a data set that represents point values of water current speed. I would like to run the IDW only within the water area of another shapefile that shows the shape of the water ...
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1answer
153 views

Understanding symbology in IDW interpolation using QGIS 2.18

Continuously to Understand ramp color interpolation using QGIS 2.12, I used IDW interpolation on those height point without inserting the real values (minimum value is 8 meters, maximum value is 584 ...
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2answers
266 views

Extrapolating surface in ArcGIS Desktop?

I'm trying to calculate the volume of a landform under water in ArcGIS and here's what I decided to do: Convert the raster of the bathymetry that I had to a gridded point dataset using Raster to ...
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1answer
542 views

SAGA IDW interpolation algorithm has been changed?

Yesterday, I try after a long time to make an IDW interpolation on a point layer in Qgis 2.18 with SAGA tools. I use same parameters as before on Qgis 2.14, but the result is quite different. Raster ...
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1answer
1k views

Creating Digital Elevation Model from Contour Data using QGIS? [duplicate]

In ArcGIS I used to create DEMs from contours with ease. However, we recently opted to stop using ArcGIS (for various reasons), and switching to QGIS. The reason I use contour data is it is all ...
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0answers
175 views

Using IDW with ModelBuilder?

I am attempting to create some groundwater elevation rasters using IDW. There will be a raster for every month for about the past 10 years. Since readings are taken from wells once a month, I normally ...
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0answers
142 views

Cross validation: Spline with barriers

When interpolate a raster surface, using Spline with barriers it is possible to run cross validation for this method? I have a raster and i want to find the RMSE for IDW and Spline with barriers in ...
2
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1answer
630 views

IDW interpolation of values from raster in ArcGIS

I've been tasked with obtaining z-values for a large point set from a 2 m raster, but rather than extracting values directly from the raster, or with bilinear interpolation, I've been asked to use ...
2
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2answers
185 views

What does 'Weight Field' in IDW interpolation mean?

I am trying to figure out how the Weight Field option of Geostatistical Analyst IDW in ArcMap 10.3 works. On IDW - ArcGIS Desktop Help I can find just this simple explanation: Used to emphasize ...
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0answers
57 views

Cross-validation error threshold in ArcGIS

I'm learning the Geostatistical Wizard toolset in ArcMap 10.4.1 and I am performing the cross-validation step in an IDW interpolation. I have done some research regarding the process of cross-...
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0answers
74 views

WEKA for IDW evaluation IN QGIS

intento evaluar una interpolación IDW realizada en QGIS y desconozco la manera de validar o evaluar su ajuste (y con cuales herramientas). Pero he descubierto WEKA como una alternativa para la ...
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1answer
58 views

Elevation profile and chemical concentrations

I have a IDW layer showing the pattern of a chemical concentration. I have also created an elevation profile across the same area. Is there any way to include the IDW measurements with my elevation ...
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1answer
956 views

What is the unit of “output cell size” in IDW in ArcGIS?

I have a wind speed point data which I interpolated using IDW. While interpolating, it asks for output cell size. I am confused as in it is in which unit? My data is in UTM projection and WGS 84 ...
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1answer
224 views

Inverse distance weighting variable search radius based on third variable [closed]

I am trying to perform inverse distance weighting (and possibly kriging), but want to base the search radius on a third variable: high population density -> small search radius low population density ...
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1answer
571 views

How to compare a TIN and IDW-derived raster DEM quantitatively?

I'm a student and got the assignment to compare a TIN with a height raster 'quantitatively' and I'm not quite sure how to proceed. I tried subtracting the one from the other but it doesn't seem to be ...
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0answers
37 views

Determining search variable when using Inverse Distance Weighted Interpolation? [closed]

When using IDW interpolation in ArcGIS, how should I determine the number of nearest input sample points to be used to perform interpolation? The default number is 12, but it may be incorrect.