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

learn more… | top users | synonyms (1)

4
votes
0answers
84 views

Interpolating species data from sample points in a small area

I have sample data from a small site (10 acres) which shows the number of occurrences of a particular species of snail over two sampling periods (fall and spring sampling). I want to try and ...
4
votes
0answers
335 views

Weather conditions forecasting / interpolation

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 ...
4
votes
0answers
96 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 ...
3
votes
0answers
26 views

Preparing data for semiovariogram analysis in ArcGIS with large sample sizes?

I am working on a statewide project to create surface water quality grids from point samples. In some instances, we have large sample sizes (n>50,000) which is problematic when creating ...
3
votes
0answers
82 views

DEM from contours

I have problem to create a DEM from contours. I know it is very simple but I can not make it work. I tried everything but nothing has happended! The shapefiles I've got are a con_lin and a con_pol ...
3
votes
0answers
55 views

Elevation interpolation along a (sewer) line

Here's what I want to do. I have a vector sewer line feature class that contaings a field for the high invert elevation and one for the low invert elevation. I can turn them into a raster no problem ...
3
votes
0answers
35 views

3D distance and topography

I have a set of points and want to find out the nearest distance to a water body (poly lines) taking into account the terrain and get a surface distance calculation. I understand that the way is to ...
3
votes
0answers
93 views

Validity of ordinary kriging of polygon centroids

I'm in a discussion with a colleague who believes that kriging should not be used to interpolate a surface from polygon based data (i.e. with kriging applied to centroids), because this effectively ...
3
votes
0answers
199 views

Empirical Bayesian kriging - does data need to be normal?

With empirical Bayesian kriging (ebk), does the data need to be normally distributed? If I apply a normal score transformation, my data is still not normal. Is ebk kriging thus an invalid ...
3
votes
0answers
286 views

Create a path following a road, interpolating from a set of points

I have several hundred vehicular routes within a city from which I wish to create shapefiles. These take the form of directions such as "From Green Street, turn left into Brown Street, Right into ...
3
votes
0answers
202 views

Is there a way to create raster by interpolating point values using GeoTools 8.2?

im new in using GeoTools (8.2). I was able to create shp from asc file which contains my data. Now my question is is there a simple way to create (interpolate) a simple shapefile (only points) to ...
3
votes
0answers
130 views

Which geostatistical tools to use to determine surface changes over 40 years?

I have a data from the Weather station with SWEmax (snow water equivalent) collected over 40 years. I need to interpolate the data over my river's watershed and then, somehow, determine the ...
2
votes
0answers
35 views

Interpreting results of QGIS intepolation and Heat map from point shapefile

I have taken a step interpolation and heat map of the data point shapefile (building Centroid) with QGIS ver-2.8.1, as shown below. My question are: What is the difference of the two methods? How ...
2
votes
0answers
29 views

Expand data set by interpolation

I have a data set that is classified into 7 landcover classes. I've been asked to expand this data set to a new boundary. My question is How can I interpolate my existing data out to meet the new ...
2
votes
0answers
50 views

3D interpolating

Our final year project domain is soil contamination modeling. We collected soil samples at the depths of 0.3 cm ,0.5cm , 1cm , 1.5 cm in about 25 locations. We considered 8 contaminants- p h, sodium, ...
2
votes
0answers
117 views

best method for gridding or interpolating elevation data

I wonder if someone can recommend the best method for gridding elevation data in QGIS, GRASS or similar. The elevation data I have is collected along 1m spaced lines at approximately 1 reading per ...
2
votes
0answers
74 views

How to Interpolate very large datasets in QGIS?

I am working with a very large set of point data, (XYAttribute) which I wish to display as a raster. I've been using Interpolate, this is successful but very slow. I have other programmes that ...
2
votes
0answers
1k views

smoothing results from scipy griddata interpolatioin

I am using the griddata interpolation package in scipy, and an extrapolation function pulled from fatiando: import numpy as np import scipy from scipy.interpolate import griddata import ...
2
votes
0answers
230 views

how to make decent sense from scattered river depth measurements

I sampled river depth at scattered positions and I want to be able to make a map and GIS layers out of it. My problems are: As the river meanders the interpolation I do in scientific packages i,e. ...
2
votes
0answers
146 views

How to calculate the grid point precipitation from the station data?

I have a problem to convert my hourly station precipitation data to the surrounding grid points. I need to convert 4 station hourly rainfall data to 18, 60, and 240 grid points for 0.0625,0.03125, ...
2
votes
0answers
520 views

z-Coordinate and interpolation plugin in QGis

I've a csv file that includes weather stations locations (x,y,z) and precipitation values. I loaded the file by using add delimited text and then converted it into a point shapefile WS84. By using the ...
2
votes
0answers
143 views

Interpolate current Course value of GPS using previous Course values

I have a set of GPS data with Lat, lon and Course. I need to interpolate current value of course, using previous values of Course. The formula I am using is not accurate in curves.In C language I was ...
1
vote
0answers
24 views

How to interpolate a Raster DTM

I have a GeoTIFF DTM produced from Agisoft Photoscan at 0.05 m resolution. However the interpolation used by the program to remove the riparian vegetation has used points from the channel, thus ...
1
vote
0answers
37 views

Geoserver render interpolated polygons

First post here on the GIS forum, ill try to do my best explaining my situation. Im looking for solutions or pointers in the right direction. So, right now I'm experimenting with Geoserver. The data ...
1
vote
0answers
20 views

give importance weighting to sample points in an IDW-interpolation

I am trying to make an IDW-interpolation in arcgis 10.1. In my sample file i have points with the same x,y and z values. According the arcgis-resource-site, the points are considered duplicates and ...
1
vote
0answers
33 views

How to visualize Smoke Dispersion by interpolating point data

During the last weeks, I am trying to develop an application within my current working project, which aims to simulate smoke dispersion of fire incidents. Software used: ArcGIS for Desktop/Server ...
1
vote
0answers
19 views

Coordinates interpolation for video frame synchronization

I'm taking an aerial video with gps coordinates. Here's the problem: the video is x frame at second, and the gps module gives me coordinates every second. So I've the coordinate of the first frame for ...
1
vote
0answers
23 views

Strange interpolation with natual-neighbor metod

I have base shape file and try to use different interpolation methods to get image like this: This layer is constructed using point to raster conversion. Generally, interpolation methods as idw ...
1
vote
0answers
35 views

How do Natural Neighbor and IDW assign values to pixels?

According to ESRI's help files, NN interpolation calculates a value for a "query point", yet the output is ofcourse a raster. I understand how the value of this query point is calculated based on the ...
1
vote
0answers
53 views

Cross validation after kriging, in ArcGIS

I performed kriging interpolation using the kriging interpolation tool in ArcToolbox, not the Geostatistical Wizard method. However, how do I determine the cross validation without using the ...
1
vote
0answers
39 views

Gradient fill based on scores (similar to elevation)

I'm rather new to using GIS (QGIS, specifically). I've mapped out a cohort of around 550 patients across Long Island, New York based on their full address by using MMQGIS plugin. This data is ...
1
vote
0answers
59 views

Calculate surface map from PostGIS

We need to create surface maps from the website. The data is stored on PostGIS (2.1) as a table of Point geometries with a field indicating a thematic value. The optimal solution would be to produce ...
1
vote
0answers
37 views

Problem with QGIS raster interpolation from a point shapefile after duplicating the shapefile

Let me explain a problem I had with QGIS to see if somebody else has experience it. I created a raster from a point shapefile through the Raster-> Interpolation menu with no problems. After that, I ...
1
vote
0answers
53 views

Does interpolation create a vector or raster?

I have been reading about interpolation and am trying to understand whether interpolation results in a vector or raster. Say I have a layer of points and I am interested in creating a raster that fits ...
1
vote
0answers
10 views

Finding polygon from two arcs using CLI tools or some library

I'm trying to convert from textual representation into a set of arcs and lines. The 'input' I have is: The area is within lines joining two semicircles with a radius of 0.67 NM centred on: 641139N ...
1
vote
0answers
63 views

Optimal distance and power exponent in IDW

I want to apply IDW interpolation for my region of interest, and through leave-one-out cross validation I want to find the optimal values for the distance parameter and the power exponent. I know that ...
1
vote
0answers
54 views

Interpolated raster not aligned with the vector data (QGIS)

I have loaded some tab delimited text data into QGis to interpolate the points. When I get to the interpolation (IDW) part everything breaks down. The output raster file does not align with the ...
1
vote
0answers
53 views

Interpolation of SRTM data

My situation: I need to interpolate the 3" srtm data for a game I'm developing (it's like Minecraft - voxel style). I downloaded the srtm data from viewfinderpanoramas.org. My aim is to get the height ...
1
vote
0answers
41 views

Hydrological triangle (geoscience) with QGIS 2.6.1

I want to interpolate ( TIN-Interpolation) between variable points (the best within a triangle) WITHOUT producing new shapefiles (or csv data file). So what I have now is an interpolation of all ...
1
vote
0answers
23 views

Is there a standard for determining the accuracy of a polygon interpolation technique?

I'm looking into polygon interpolation, and was curious if there are any standards for determining the accuracy of polygon interpolation techniques. I've been looking through papers and lecturers ...
1
vote
0answers
23 views

How to draw a surface with Natural Neighboring

How can I use the natural neighbouring method with JAVA API of ArcGIS? I mean that I have points and z values of these points and I want to interpolate these values on an arbitrary map.
1
vote
0answers
65 views

How to include 3D break lines in QGIS raster interpolation

I wish to add a break line to an interpolation of a set of survey points to simulate an elevated ridge in the survey area. Using QGIS 2.6 on Windows 7. I have created a polyline shapefile with a ...
1
vote
0answers
67 views

Maxent output clips to minimum extent of all input variables

I am experiencing an issue with the spatial extent of my output ASC files. I am using the UK Land Cover Map (LCM) 2007 at 25 metres resolution as a categorical variable in my Maxent modelling, ...
1
vote
0answers
70 views

GIS grid linear interpolation for a given point

Suppose that I have a GIS grid. I need to do linear interpolation for a given point located inside a cell of the GIS grid. The locations and values of the vertices of each cell in the grid are ...
1
vote
0answers
94 views

network based interpolation methods, which one could I use?

I need to interpolate traffic data consisting in raw number of vehicles passing across certain points, where counters are. It is evident I haven't a uniform distribution of points and values about ...
1
vote
0answers
481 views

Error when kriging in SAGA: grid file could not be opened

I have a point and a polygon vector shape (shapes) which I want to interpolate by using the saga tool "Ordinary Kriging". I always get the following error message: Oooops! The following output ...
1
vote
0answers
90 views

Statistically compare two density maps?

I (will) have a modelled distribution and an observed distribution of animals. If I were to interpolate these position datasets to reflect some density distribution (perhaps using a kriging ...
1
vote
0answers
89 views

Qgis raster interpolation shift

Using Qgis 2.0.1, I'm attempting to interpolate a large point dataset (n > 400K) to a raster surface. I'm using the IDW option in Raster>> Interpolation>> Interpolation, and the resulting ...
1
vote
0answers
78 views

Interpolating counts within irregular-shaped regions in a country?

GIS novice here. We are trying to estimate the total number of toxic waste sites within the country of Ghana. We will be dividing up the country into quadrats (with some irregular shapes on the ...
1
vote
0answers
159 views

Interpolating shapefile of points to grid using Java?

I am looking for a method/prog/library(java) to interpolate points from a shapefile to a grid (file). I have seen arcgis can do that but i am looking for something free. More specific: i have ...