Questions tagged [interpolation]

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

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40
votes
4answers
59k views

Deciding what interpolation method to use for resampling raster data?

Are there hard and fast rules about which interpolation methods are suited to each kind of raster data?
5
votes
1answer
410 views

Slope layer with false results in QGIS? [duplicate]

After the DEM creation, I wanted to create slope layer. However, the result has not satisfied me. I don't think the slope map is correct. Have you ever encountered false calculated terrain map? ...
42
votes
9answers
26k views

Open source methods for kriging?

I have a point dataset which I'd like to Krige, ideally using an open-source software package. If possible, I'd also like to choose the semi-variogram model during the process to improve the ...
6
votes
3answers
9k views

Resizing image resolution in ArcGIS Desktop?

I have NDVI images (250 m) and Soil map (1000 m). How can I change the resolution from 1000 m to 250 m, so I can compare/work with them?
12
votes
1answer
2k views

How do you use GRASS's v.kernel?

I am flummoxed on how to use GRASS's v.kernel. I have a vector layer of around 2.5 million points. I want to make a heat map using v.kernel to show concentrations, since I have variable instances ...
20
votes
3answers
8k views

Smoothing/interpolating raster in Python using GDAL?

I am developing in Python and using GDAL from OSGEO to manipulate and interact with rasters and shapefiles. I want to take a shapefile that has point features and interpolate it into a surface raster....
5
votes
4answers
2k views

How to compute an interpolation raster from the python console in QGIS?

I am trying to add an interpolation layer based on an existing vector layer by using the Python Console (initially in the menu Raster/Interpolation), but can't find anything related in the ...
8
votes
6answers
2k views

Interpolation of multibeam bathymetry using ArcGIS Desktop?

I'm trying to make a 3D map with multi-beam bathymetry (65536 features, xyz), but it seems that the interpolation methods are too rigid. I need to smooth the data so it looks more natural and ...
16
votes
1answer
2k views

Which interpolation technique is suitable for a bathymetry of a small lake?

This is a lake of approximately 13 ha with 81 sampled depth points in about 10 transect lines: Previously in ARCgis with a 50 ha lake and about a 100 depth sampling points, I got decent output with ...
8
votes
1answer
2k views

Partially updating raster (DEM)?

How to update an .img DEM in ArcView 9.3? I do have DEM which need to be updated only if few parts. The area to be updated has been produced in separate DEM with Spline Interpolation with Barriers. ...
7
votes
1answer
6k views

Converting points to raster in ArcGIS?

How do I create such map from point data? I am using ArcGIS 9.3 and 10
6
votes
2answers
6k views

Picking coefficient in Inverse Distance Weighted method of QGIS?

I'm using QGIS 1.8.0 to interpolate weather data. This is, I have a weather station located in say, A and C. With the Inverted Distance Weighting or Triangular Interpolation methods, I can know/...
3
votes
3answers
2k views

Using National Agriculture Statistics Service (NASS) county level crop data to estimate crop acreage in hydrologic regions?

National Agriculture Statistics Service (NASS) provides county level crop (Corn, Soybean, Sorghum, etc) data. I want to calculate crop acres on each subwatershed from the county based data. I'm ...
13
votes
3answers
3k views

How to interpolate GPS Positions in PostGIS

I have a PostGIS table of GPS positions for every five seconds: 2011-01-01 00:00:05, POINT(x1,y1) 2011-01-01 00:00:10, POINT(x2,y2) 2011-01-01 00:00:15, POINT(x3,y3) ... I'm looking for a query that ...
7
votes
2answers
14k views

Creating DEM from point data in CSV files using ArcGIS Desktop?

I have a lot of csv files which contain point data containing height, aspect and slope measurements at a resolution of 12,5 meters. I need to create a dem from this data and have ArcGIS 10 with ...
4
votes
1answer
674 views

Debugging errors of SAGA interpolation algorithms in QGIS Processing?

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter what technique I use I end with the following errors. As stated in the OGR tab QGIS 2.0 is unable to open a ...
23
votes
1answer
29k views

Choosing IDW vs Kriging Interpolation for DEM creation?

I'm trying to create a DEM using point data spaced very regularly about 10m apart. The area I am interpolating is an educational facility with many flat parking lots and football fields but still has ...
23
votes
3answers
6k views

What resampling technique should be used when projecting aerial photos?

I'm doing some time-intensive projecting of aerial photos, and I'm curious - what resampling technique is best to use on aerial photos? In ArcMap, my options are NEAREST, BILINEAR, CUBIC, and MAJORITY....
8
votes
3answers
2k views

Shortest Path using interpolated OSM points

I have a set of GPS points which I have snapped to the OSM network. In the below screenshot GPS points are red, snapped points are green. I want to calculate the shortest path that includes all of ...
10
votes
5answers
2k views

What is the best technique for interpolating soil depth from sample points

This is my first post here. I have some points from a soil depth survey and I need to interpolate the depth for a whole area. What is the most appropriate technique for this and is there anything I ...
12
votes
3answers
3k views

Spatio-temporal interpolation in R or ArcGIS?

I'm trying to calculate average rainfall value from a number of points using Inverse Weighted Distance tool in ArcGIS 9.3. My problem is that: each point has it own time series, therefore the ...
6
votes
2answers
2k views

Kriging method to use for rainfall?

I am working on an rainfall analysis and I have to interpolate some datas with kriging method. Is co-kriging suitable for the rainfall analysis?
10
votes
2answers
893 views

Should point data be equidistant projected when using ArcGIS IDW spatial interpolation?

I am wondering if anyone can clarify whether point data should be projected to an equidistant projection when using ArcGIS IDW spatial interpolation? I am working on a dataset from Western North ...
5
votes
2answers
989 views

Method for estimating accuracy in spatial interpolation?

When using a spatial interpolation method (any method) without having a way to validate it, besides sampling some points out, is there a way to count as well with the mean distance between ...
5
votes
1answer
932 views

Cross-validation of TPS and kriging outputs from the fields package in R

I am looking for existing package or functions that will allow me to cross-validate multiple outputs of Thin plate spline (TPS) and Kriging from the fields package. Does anyone know of any available ...
4
votes
2answers
884 views

Kriging values greater than the most extreme value of the input layer?

I'll admit I don't understand kriging to the fullest. Yet, I've read that the weights should add up to 1 as in IDW and Natural Neighbors. However, surrounding the biggest elevation points of my ...
6
votes
3answers
1k views

Interpolation of Three Data Points

I have three location points with weather data. It's a 10-year composite of temperature values which means I only have three values for three locations for ten years. The distance between points is ...
5
votes
1answer
2k views

Interpolation plugin error message WKB access out of bounds with QGIS 2.14 & 2.18

I am new to QGIS. I am trying to construct a DEM from contour lines by using QGIS 2.14.0. (and later 2.18) I am doing this by using a clip rectangle tool (geoprocessing tools) on top of the contour ...
4
votes
1answer
2k views

Error in In predict.gstat in R

I am trying to do kriging by gstat package through R. Here is my Code: krg<-krige(var ~ 1,data,grid,model=vgm,nmax=30) But each time I recive this warning: 1: In predict.gstat(g, newdata = ...
3
votes
1answer
622 views

Integrating DEM within kriging and other interpolation methods?

I would like to see the difference of including DEM in interpolation from without. Some studies on climate data interpolation suggest that interpolation performs better with DEM. How do I do this in ...
3
votes
1answer
228 views

Does raster interpolation recognize multiple z values for one x, y point?

I am working with lithological data, where I have multiple z depths for one set of coordinates. How is this read by the raster interpolation toolset? Does it utilize only one or all of these z values? ...
2
votes
3answers
1k views

Is kriging an exact interpolation method?

Can kriging be an exact* method? For example, when optimized with the Geostatistical Wizard? Or in any other way? (as far as I know, "normal" kriging isn't an exact method). *exact: predictions at ...
2
votes
1answer
4k views

TIN Interpolation using a vector layer

I'm writing a plugin in QGIS and I'd like to generate a TIN surface using a vector layer with x,y and z (interpolation attribute). The idea is to visualize the same result like in the Interpolation ...
2
votes
1answer
548 views

What resampling method is used in gdal_merge?

I am using the gdal_merge python script to merge rasters that have slightly different, though similar, input resolutions. The documentation advertises that it can handle different resolutions, and in ...
1
vote
1answer
116 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 ...
1
vote
1answer
360 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 ...
1
vote
2answers
745 views

Using ArcGIS API interpolation functions (idw, kriging, splines) in my own dataset?

Does ArcGIS API provide interpolation functions, like if I want to interpolate from my own set of values? I know that ArcGIS provides functions for interpolation like IDW, Spline and Kriging etc, ...
0
votes
1answer
183 views

retrieve coordinates of all weather stations that falls in Germany in R [closed]

I have a historical temperature and precipitation observations in each individual txt file for the globe by year (I have total 35 txt file for yearly temperature/precipitation), and in my research ...
7
votes
1answer
8k views

Plotting map resulted from kriging in R

I want to plot a map weighted by prices. I got a data frame of latitudes, longitudes and prices: > str(data) 'data.frame': 1253 obs. of 3 variables: $ lon : num 11.2 11.1 11 11 11.3 ... $ ...
19
votes
2answers
10k views

Minimum number of samples for kriging interpolation

I get some data with number of specimens with a request to interpolate it using kriging method. After some investigation it appeared that kriging results (performed in ArcGIS Geostatistical Analyst ...
15
votes
7answers
5k views

Looking for interpolation tool to produce river bathymetry (topography) from sections

As per the title, I am looking for a tool that can produce bathymetry of a river from cross sections. Although people who may know such tools probably will not need any explanation why this kind of ...
12
votes
4answers
15k views

Bilinear interpolation of point data on a raster in Python?

I have a raster that I'd like to do some point interpolations with. Here is where I'm at: from osgeo import gdal from numpy import array # Read raster source = gdal.Open('my_raster.tif') nx, ny = ...
12
votes
2answers
1k views

PostGIS interpolation / triangulation options

I'm looking for an open source workflow to automate DEM construction. We have a series of sites that fall within a LIDAR dataset. We want to create site specific DEM's for each site, and we're ...
11
votes
4answers
7k views

How to interpolate temperature correctly?

I tried to interpolate the mean average annual temperature to produce a "realistic" surface. In QGIS I used Raster-Interpolation-Interpolation. Both methods TIN and IDW did not deliver a "realistic" ...
6
votes
2answers
2k views

Creating geodatabase from CSV using python

I have a file with weather data (daily) for multiple weather stations for multiple years. I am looking for some python script to automate the database creation process and its interpolation on a daily ...
4
votes
1answer
283 views

Preparing dataset to perform co-kriging in R gstat?

This is the first time I'm using co-kriging in gstat. My problem is that I'm not sure how to prepare the data frame to supply to co-kriging when the variable of interest and auxiliary variables are ...
7
votes
2answers
3k views

How to Create Contours for Zonation

I'm still new in the world of GIS. I'm currently doing some zonation with "test points." Each has its own coordinates and "P" value. I want to make contours of these data, to divide the whole area ...
2
votes
1answer
2k views

Downscaling raster images in Google Earth Engine?

How can I downscale raster images using basic interpolation methods in Google Earth Engine? For example, I want to resample Landsat image from 30m to 10m, but I cannot find corresponding functions in ...
10
votes
4answers
5k views

Kriging with barriers in ArcGIS Desktop?

I am trying to do interpolation in a coastal area with data points in several rivers emptying into a bay and on opposite sides of peninsulas. I have created a coastline layer to use it as a barrier ...
7
votes
5answers
2k views

What type of interpolation to visualize metal detection survey data?

I have about 500,000 points collected in a linear grid pattern over a 1 km2 area. The points were collected as part of a metal detection survey. Each point has X,Y and Coil Response mV (min -675.38 ...