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Questions tagged [interpolation]

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

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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 ...
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?
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
7k 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....
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....
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 ...
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 ...
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 ...
13
votes
3answers
1k views

Modelling of rent prices - which interpolation method to use?

I have national dataset of ~1,4 million households. There I have information about rent, size (number of rooms and m2) and some additional characteristics of each household. I'd like to use this data ...
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 ...
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
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 ...
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 ...
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
8k 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" ...
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 ...
10
votes
2answers
898 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 ...
10
votes
1answer
951 views

Interpreting semivariogram with high nugget effect?

I made a semivariogram in R using package gstat, variogram() function. I want to see if there is spatial autocorrelation in the residuals of my model (species abundance as a function of habitat, ...
10
votes
1answer
812 views

How to grid unevenly sampled categorical data?

I am looking for a method for gridding categorical data. I have extracted from nautical charts and field sheets a collection of points specifying the nature of the surface of the bottom of the ocean. ...
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 ...
9
votes
1answer
2k views

R gstat krige() - Covariance matrix singular at location [5.88,47.4,0]: skipping

When I want to perform the kriging it only works sometimes, depending on what values I use in my datatable. As a result of the krige function I get for var1.pred: NA NA NA ... and var1.var: NA NA NA .....
9
votes
3answers
2k views

Spatio-temporal block kriging with R package gstat?

In the documentation of sp I saw that the coords argument of the SpatialPolygons function only accepts 2 columns. Is it not possible to create 3-dimensional polygons? I am doing spatio-temporal ...
9
votes
1answer
195 views

Interpolating degree data using QGIS?

I want to create wind maps. There is an introduction for ArcGIS and for QGIS. As I don't have access to the Spatial Analyst, I gave the QGIS-version a try. However, I don't know how to interpolate ...
8
votes
1answer
2k views

How to choose raster interpolation method?

I work with a dataset of ~1.3 million residential buildings; each of them is described by a normally distributed variable ranging from 0 to 100. The dataset covers whole Switzerland so there are ...
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 ...
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. ...
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 ...
8
votes
1answer
864 views

Hex grid value interpolation in POSTGIS

I have a table of tessellated hexagons that I created as a hex binning grid to cover an area. I've then overlaid a point set to give some of the hexagons a value, see diagram:- The shapes with value ...
8
votes
1answer
1k views

Accurately interpolating elevation from contour lines in QGIS?

I’m trying to interpolate elevations from contour lines (~70000 at 1m intervals, spanning ~20km^2) in QGIS.  When I interpolate using Inverse Distance Weighting (IDW) in the Interpolation plugin it ...
8
votes
1answer
184 views

Estimation of values for unsampled points

I want to measure biomass on a coastal mudflat. I can only access points inside the polygon. Are there any methods available that would allow me to estimate values of the points outside of the polygon,...
8
votes
0answers
989 views

Weather data interpolation? [closed]

I'm trying to carry out weather conditions interpolations. I have information of 92 weather stations for 800,000 km2. As you can imagine the extension of land is huge and I need some kind or weather ...
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 ... $ ...
7
votes
2answers
4k views

Strange spatial interpolation results from ordinary kriging

I'm using Ordinary Kriging to interpolate a set of spatial data. I'm working on different sets which represent different days of measurement. I get good results, apart from one specific set. Will post ...
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 ...
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 ...
7
votes
3answers
831 views

Interpolate data from multiple gpx tracks

I have a number of GPX tracks of the same road. But due to GPS error they are not accurate enough (20-30m off). I'm wondering if I could interpolate those multiple gpx tracks into single one. If an ...
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
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 ...
7
votes
3answers
2k views

Kriging with barriers in R?

I wonder if there is a way to interpolate xyz points in a raster within certain bounds using R? In ArcGIS this is called interpolation with barriers. I wonder if there is something similar in R? I ...
7
votes
1answer
749 views

Spatial interpolation of 30 weather stations to other areas

I have monthly (and sometimes daily) data on temperatures from about 30 Swedish weather stations in the mid-19th century that I want interpolate to the whole country. I'm using ArcGIS and Stata. For ...
7
votes
1answer
2k views

How to interpolate polyline or line from points?

We have a lot of points, but with no timestamps to create ways. For now, I've created a sample of the way the points traverse. It's in here, this way can be compared with a Google one. I haven't ...
7
votes
2answers
347 views

How to handle interpolation of multiple (quality) tiers of irregular data?

I'm going to try to provide a high level overview of the issue - realizing that more details/info will be necessary - but I don't want to write a novel that seems too overwhelming for people to ...
7
votes
2answers
2k views

Interpolating Maps - Statistical Learning Techniques vs Spatial Statistics Techniques

I have recently begun experimenting with the interpolation of variales over a whole country. I have good sized training set where I have several dependant variables (continuous and categorical) ...
7
votes
1answer
336 views

Kriging to calculate forest biomass?

I am trying to create biomass map using Kriging from ground sample point. I have about 150 and 53 point plot for dense and sparse strata. The data is not normal so I have transformed it. After ...
7
votes
1answer
419 views

Interpolating Daily Values from Monthly Grids using QGIS?

I am currently performing a bioclimatic analysis using monthly averaged climate grids. One particular calculation, Growing Degree Days, relies on daily maximum/minimum temperature and a threshold ...
7
votes
4answers
3k views

What are the most efficient Geographic Weighted Regression packages?

What are the most memory efficient open source packages for calculating a geographically weighted regression (GWR)? I am in a situation where I need to do a geographically weighted regression on a ...
7
votes
1answer
358 views

Interpolating points observed with different time duration

I am doing spatial interpolation with a group of points. Some points have complete observation of events: for a period of 24 hours we have observed N events in each point. These points have N events....
7
votes
1answer
2k views

Are special interpolation techniques required for weather data?

I've downloaded a series of weather observations from the local weather agency - it comprises around 1,000 points spread non-uniformly across Australia, with a greater density of points located near ...
7
votes
1answer
397 views

Interpolation error using QGIS 2.8.3 with nearest interpolation function

With several point imported from .csv file containing the information of longitude, latitude and VALUE. To represent the 2-d distribution of value, I want to interpolate the sparse point into 2-d ...
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?