1
vote
2answers
66 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
96 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 ...
0
votes
0answers
16 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 ...
1
vote
2answers
45 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
155 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: ...
3
votes
1answer
112 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 ...
0
votes
0answers
49 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 ...
2
votes
0answers
158 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. ...
4
votes
0answers
147 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 ...
1
vote
1answer
481 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 ...
0
votes
0answers
81 views

Weather interpolations QGIS

does any one know how good are the weather interpolations that QGIS carries out? Do you have any other suggestions or better methods to do them? Please let me know. Thanks in advance!
0
votes
0answers
96 views

memory restrictions in QGIS Interpolate?

I am trying to make a DTM from contour lines (.SHP) using the Interpolate tool. The tool runs fine when I clip the data into smaller areas, but when running for larger areas, it crashes QGIS. Are ...
1
vote
1answer
128 views

Restricting Tin interpolation in QGIS

I am trying to do a bathymetric map for a lake using QGIS. However, I see no option to impose a mask so interpolation does not extending beyond the boundaries of my lake. I have traced around the ...
2
votes
0answers
127 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 ...
0
votes
0answers
70 views

Mapping point data according to it respective value

The project I am trying to do is to map sum water quality (based on trace metals) data into QGIS. Each of the trace metals have their respective values and need to represent their concentration ...
1
vote
2answers
562 views

Are there only two methods of interpolation in QGIS?

I did recently a map of maximum temperature for specific area in Quantum GIS 1.8.0 and its interpolation. However, I was wondering if there are only two method of interpolation, apart from ...
0
votes
1answer
76 views

How to add information to an attribute table?

I'm working with qgis 1.8.0 and did the following: 1.-Divided my shapefile into 830 features (small rectangles). 2.- Added to my shapefile several points containing weather information using the "add ...
0
votes
1answer
44 views

Sampling from interpolated data layer

Im working with QGIS 1.8.0 and wanted to ask you how can I assign to each of the small squares of the map (I have the coordinates of the center each of them) values from an interpolated data layer as ...
0
votes
1answer
137 views

Convert / interpolate delimited text csv points grid to surface

I've got 12 delimited text csv files with regular pseudo-gridded points for temperature and salinity which look like this when zoomed in (inc distances) and this when zoomed out. I'm trying to convert ...
-2
votes
1answer
178 views

What tool(s) in the Sextante toolbox in qgis 1.8 can be used for interpolation? Kriging and spline

I have looked at every single one and can not figure out which on can be used.
0
votes
0answers
51 views

Why does TIN interpolation ignore some input points?

i have xyz-files (laserscanning, but already as a regular raster) that i converted to vector files. everything is fine, but when i try to convert them to raster via interpolation (TIN, 1x1 meter ...
1
vote
0answers
46 views

Generating “weighted convex hull”

sadly I don't have any keyword that reflects what I'm looking for: I have a vector layer consisting of points, which have an integer attribute ("signal quality" here), that I want to plot as a convex ...
1
vote
0answers
206 views

“topo to raster” tool

is there any analogue of "topo to raster" tool (ArcGIS) in QGIS? I need to creates surfaces from shp for some cases from points and for some from lines and this instrument is very convenient.
2
votes
0answers
329 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 ...
4
votes
1answer
270 views

Is it possible to do spatial interpolation using points in a field?

I would like to use Quantum instead of ArcGIS to make field map but before, I need to know if its possible to do spatial interpolation with definited points in a field (ex. pH points). Is there a ...
5
votes
2answers
343 views

Spatial Analysis with Factors/Classifications

When doing analysis on spatial data with associated information that is numeric, it is possible to use techniques such as Kriging or Interpolation or Cluster Analysis to find out interesting ...
4
votes
4answers
523 views

TIN interpolation crash in Qgis

I have problems using the function TIN(linear) interpolation in Qgis. The program crashes when larger areas is interpolated. Map properties: vector map, Geometry typ = Point, features in this ...
7
votes
4answers
2k views

How to interpolate temperature correctly?

I tried to interpolate the mean avyerage annual temperature to produce a "realistic" surface.In qgis I used Raster-Interpolation-Interpolation. Both methods TIN and IDW did not deliver a "realistic" ...
0
votes
1answer
1k views

How to install sda4pp plugin with missing repository in QGIS

I see that the repository for the sda4pp plugin went down in 2011. Does anyone know if there is another way to download the plug-in with the repository missing? If this plug-in is no longer ...
1
vote
2answers
412 views

How to batch process (100s) of interpolations in QGIS or other open source software programs?

Is there an efficient way to run 100s of interpolations in QGIS or other open source software programs? I have groundwater contamination data collected from monitoring wells at about 800 different ...
3
votes
1answer
193 views

How to calculate maximum distance to an interpolated value along a contour in QGIS?

I'm planning to enter concentrations of groundwater contaminants collected from well locations into QGIS and then use interpolation functions to create contours of the groundwater plume. Can QGIS ...
2
votes
1answer
315 views

How to overlay my interpolation within the boundaries of Quebec?

I am trying to create interpolated maps within geographical borders. I have the coordinates and values to the points I am trying to interpolate. I also have a map of the geographical land mass in ...
1
vote
1answer
424 views

How to use buffers to estimate the attribute data for a given polygon?

I have two layers: point and a polygon. The point layer has lat/long and I have created buffers of a 1/4 mile. The polygon layer has data such as age and income. Is there a plug-in that can ...
2
votes
2answers
218 views

Hand fit curve and then apply to time series of rasters, make a map. How?

Maybe a data management problem, not too sure, but likely a challenge which someone has dealt with before. I have a time series of rasters. I can summarise the information by taking averages of each ...