Tagged Questions

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

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0
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1answer
143 views

Why do I get these bands on my Height/Dem/Raster

I can't seem to get rid of them, and I've no idea (ok scrap that, I have a vauge idea) whats causing them. First an apology, yes this is quite a large pic apologies, but here goes: How to ...
0
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0answers
72 views

Issues creating slope raster layer from a point layer

I'm trying to create a slope raster layer using QGIS 2.0 on Windows XP. I started with a points layer with the Z elevation attribute. I then used the interpolation plugin to create a DEM. But, ...
1
vote
1answer
62 views

Interpolate points to lines every odd and even number

We are working in Oracle Database 11g. There is a table with sdo_geomerty column(representing a line) which contains the following : RSID, LT, LF, GEOM 584908, 30, 34, ...
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0answers
65 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 ...
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0answers
13 views

Convert ECF to Suface ECF

I'm using the 3D Earth WorldWind Model and I have a path that I want my object to travel. I set the the destination and interpolate to the end point from my current location. The problem is using ECF ...
0
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2answers
130 views

Color gradient in symbology in ArcGIS 10.1 for interpolation raster

I have measured noise and want to create with this measured points a noise map with interpolation....is there any way in symbology to create a flowing transition between the different colors for the ...
2
votes
2answers
80 views

How to interpolate population data?

I have population data (inhabitants per city and year) of 31 cities of the DR Congo for the years 1960, 1970, 1980 and 1990. I want to interpolate the population of all cities for the year 1990, to ...
0
votes
1answer
68 views

problem in spline with barriers in ArcGIS 9.3?

I am trying to use the script tool "Spline with Barriers" from arcgis 9.3 3D Analyst toolboxes. I am not getting expected output. The output is just only one value over the surface. We are using ...
1
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2answers
73 views

How to perform IDW interpolation and mean estimation on county level using ArcGIS for Desktop?

I am absolutely new to GIS. I have imported a map with information in the counties of Germany. Additionally I have added a layer with information on SO2 concentration at various measuring stations in ...
4
votes
1answer
159 views

Interpolating vertically in 3D analyst

Here is my problem: I am working on mapping pollutant concentrations in a pond from point-sampled data. There are 50 sampling locations in the pond (randomly dispersed), and at each location there ...
2
votes
1answer
106 views

How to Interpolate through ModelBuilder?

I would like to create an iterated interpolation tool through ModelBuilder. I have an excel file containing different columns and each column represents a data that will be interpolated using Spline ...
1
vote
3answers
223 views

Which interpolation method for noise mapping?

I want to create a noise map with measured point data. But i want to have a planar representation, so I need an interpolation method. Which one is the 'best' one for measured noise data? I prefer to ...
0
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0answers
12 views

Printing a label from a point layer attribute on a raster layer (GRASS)

I am interpolating with boundaries using v.surf.idc in GRASS. It works wonderfully and I fully recommend it. I am creating an animation and I use v.surf.idc to generate sequential interpolated raster ...
3
votes
1answer
218 views

GIS beginner - interpolating contour lines from TIN-model vs. Grid in ArcGIS

I am a complete beginner in GIS and taking a class right now, and we are doing some assignments in ArcGIS - ArcMap. In one of them we were given a shapefile with heightpoints. These had been manually ...
3
votes
2answers
338 views

What's wrong with my IDW interpolation function (Python)?

Original Question Can anyone see what's wrong with my custom IDW interpolation below? I know there are existing libraries that can do this for me, but for various reasons including educational and ...
0
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2answers
91 views

References to code IDW algorithm

Hi I'm new to interpolations. I'm looking for documentation to understand how inverse distance algorithm works and how to code it. My intention is to code IDW algorithm in JavaScript to see if it is ...
1
vote
1answer
53 views

QGIS 2.0 Raster Interpolation

I am trying to use the Rasterinterpolation plugin to pick up elevations from a Raster DEM for a series of vector points. Once loaded, the Plugin is accessible through Plugins Menu/ Raster ...
1
vote
2answers
191 views

Breaklines in QGIS interpolation plugin

How can I prepare data to generate a DTM using points and breaklines, but where every breakline has nodes at different heights. For example, a river valley, which regularly falls, or a dorsal line, ...
1
vote
2answers
28 views

attach point grid data non-grid points

Possibly a strange one: I have a dataset with loads of fields of environmental (explanatory) data, as a regular grid of points (black dots in image), and another dataset of sampled (response) values ...
1
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1answer
32 views

“Interpolation Toolset” is inactive in ArcGIS for Desktop 10.1

I have ArcGIS for Desktop 10.1 installed on my laptop and "Interpolation toolset" and "Raster Interpolation toolset" is Inactive. How can I get them work?
5
votes
3answers
165 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 ...
0
votes
1answer
100 views

Difference spatial interpolation and trend surface analysis

What is the difference between spatial interpolation and trend surface analysis? For example, I read a scientific study that applied a neural network to estimate a surface solely based on the x and y ...
1
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0answers
409 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 ...
1
vote
2answers
418 views

How to interpolate a point vector layer inside a boundary (polygon layer) QGIS/GRASS/SAGA?

I have a to create a heatmap of water temperatures inside a lake for which I have sample points. The map should look much like the climate maps generated by climate change models. I have the ...
1
vote
2answers
93 views

How to set lower limit to interpolation?

I have rainfall data that I want to interpolate using spline. I have done Spline Interpolation, only that the values produce negative predicted values which is basically wrong. There should be no ...
0
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0answers
22 views

Interpolation Plugin Not outputting image?

I am trying to get terrain profiles from shapefile elevation points by creating a TIN. I have been following this very helpful tutorial. At the output a new layer is created but with no ...
0
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0answers
172 views

How to write Python script for spatial interpolation?

I am new to Python. I have 5 rainfall stations in a basin of 1400km2, and I want to interpolate the daily rainfall series for 14 years. I spent a long time on this, but am unable to write a program ...
7
votes
1answer
1k views

When to use 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 ...
1
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0answers
53 views

TPS and Kriging Cross-Validation

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 availabe ...
1
vote
2answers
49 views

Which value should I assign my digitalized features?

I have a scanned an old document that contains geochemical interpolated values (no way to work with the digital file). This is the original image: And this is the digitalization I made from it: ...
0
votes
0answers
264 views

SAGA/GDAL fails to open grid in QGIS 2.0.1 on OSX 10.6.8

I want to try different grid/raster spline interpolation methods using SAGA in QGIS. I'm using the kyngchaos build 2.0.1-7 for Snow Leopard. Every SAGA algorithm I try gives the following in a popup: ...
1
vote
1answer
82 views

Finding points on an odd map projection using interpolation between known points

I have an image of a somewhat idiosyncratic projection that is a frame from a film: A geographer friend of mine said it was probably some kind of Gnomic projection, but that from the resolution it ...
3
votes
1answer
177 views

Debugging errors of SAGA interpolation algorithms in QGIS 2.0 Processing

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter technique I use I end with the following errors. As state in OGR tab QGIS is unable to open a file in C ...
1
vote
1answer
117 views

3 points meteorology stations

I want to extract meteorological data of a point which are 3 meteorological stations around it. I found that ArcGis has the capability to do it by interpolation. My essential data is wind speed , ...
1
vote
2answers
79 views

What ArcGIS interpolation tool would be most appropriate for price/square meter?

I have the price per square meter of around 13000 properties ; for the other 8000 of my shapefile the price is missing. The easiest option is to transfer the average price per square meter to the ...
2
votes
1answer
115 views

How to integrate DEM in 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 ...
4
votes
1answer
101 views

How to add points to LAS copy using liblas?

I am trying to make a copy of a LAS file while inserting new points using python liblas module. The code below creates the copy and adds the points, but for some reason the added points are not in ...
0
votes
1answer
71 views

Interpolation without a point layer in QGIS

I have a vector layer with incidence data (i.e. frequencies) and I made a graded color map from this using the above frequencies. Now I am looking forward to creating an interpolated (kriging) map ...
0
votes
0answers
68 views

Interpolation Technique

We have following solar metro logy parameter through satellite data with resolution of 100 Km^2 (10Kmx10Km) Insolation on horizontal surface Diffuse radiation on horizontal surface ...
0
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0answers
186 views

Interpolate/disaggregate point values to an existing raster grid

I have several thousands of ASCII files whose names have the following format: data_"lat"_"long".mon (e.g. data_41.21875_-116.21875.mon). Each file represents one point in WGS84 projection and the ...
1
vote
0answers
70 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 ...
3
votes
2answers
190 views

How to connect contour lines from two different sources?

How to connect contour lines from two different sources (LiDAR & Photogarametry) in order to obtain continuous and uniform contour lines layer ? how can i interpolate them together ? How can i ...
2
votes
0answers
204 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. ...
1
vote
1answer
60 views

Is it possible to specify interpolation method for zoom functions in Styled Layer Descriptor (SLD)?

To visualize images on Geoserver, I use xml file wrote in Styled Layer Descriptor (http://www.opengeospatial.org/standards/sld). I would like to specify what interpolation method would be used for ...
0
votes
1answer
102 views

How to consider more than one no data value in utility gdalwarp of GDAL

I have to do a bilinear interpolation on an image with two no data values, using the utility gdalwarp of GDAL (http://www.gdal.org/gdalwarp.html), so these two values don't must be considered in ...
0
votes
1answer
197 views

Problems with interpolating in Arcmap 10

I would be extremely grateful if I can get help with this question. I cant find anyone who had a similar problem. I am trying to make a raster from point data. My data is in .txt form and contains of ...
3
votes
3answers
842 views

Best way to assign points to nearest roads in postgis?

I'm trying to implement a simplified type of dasymetric mapping for census data. I've downloaded the Census's American Community Survey individual-level data and randomly assigned every household to a ...
3
votes
2answers
121 views

Spatial interpolation - appropriate method to estimate the accuracy of the surface

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 ...
4
votes
0answers
219 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 ...
2
votes
1answer
1k views

interpolation methods in qgis

I have a points layer and I want to create an interpolation grid with QGIS 2.0. If I use Raster -> Analysis -> Interpolation the extent of the output raster is good (rectangular shape) but it ...