SAGA (System for Automated Geoscientific Analyses) is a GIS toolbox with many modules that can be used from the GUI, command line or accessed through R,python or directly using C++.

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5
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3answers
593 views

LiDAR data density, returns per square meter

How can I compute a raster showing the number of return points per square meter using SAGA GIS or other open source software? My goal is to obtain a mask which would show me the places (cells) ...
4
votes
2answers
610 views

What is the source of horizontal and vertical striping in USGS DEMs?

When processing 30m and 10m DEM data downloaded through the National Map Viewer from the National Elevation Dataset, we noticed horizontal and vertical striping not only in the produced results, but ...
2
votes
1answer
669 views

Negative Topographic Index Values

I am getting negative topographic index wetness values in SAGA GIS - anyone else every get this? Not all negative values, but the minimum of the TWI range is negative for some steep watersheds we are ...
4
votes
1answer
596 views

Topographic Index - Why is upslope contributing area divided by downslope contour width and not upslope contour width?

In the Topographic Index calculation, a is the upslope contributing area per unit contour length. Is the "unit contour length" calculated from examining the contour widths of the downslope cells that ...
0
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1answer
71 views

How can I use polygon grid to export raster [duplicate]

I have a polygon grid which consists of 100 square polygons. For each square I need to export the raster overlay. I have ArcGIS 10.0, FME 2014, Saga-GIS. Is there a suitable tool for this or do I need ...
1
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1answer
277 views

How to do supervised image classification in saga with the help of R script or Python script

I am using Ubuntu 12.04 and want to do image classification in SAGA. SAGA has numerous classification algorithms which is not present in GRASS and QGIS. I am new to SAGA, but more accustomed to work ...
1
vote
1answer
695 views

catchment area using SAGA and Arcgis 10.2

I would like to calculate catchment area. I used D8 algorithm and running in both arcgis 10.2 and SAGA GIS 2.1.2. However, the results from two software are different. The lowest value of catchment ...
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0answers
57 views

Error SAGA algorithms in Modeller QGIS 2.2

I am using QGIS Modeller and I try to use SAGA algorithms but it doesn't work. GRASS algorithms work just fine but SAGA doesn't. I am not sure if I have to configurate something. What is worng?
0
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1answer
629 views

Is it possible to use polygons to create heatmaps?

I hope I can explain my question clearly, so here it goes: I've been fiddling around with heatmaps on QGIS for a few days, but came across a small obstacle on my way. I have a dataset comprised of ...
3
votes
2answers
148 views

Is it possible to highlight water steam sources on Landsat 7 image?

I am trying whether it is possible to view hot steam sources like power plant cooling towers and resulting cloud using satellite images. I was advised to try Landsat (needed free data for initial ...
0
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0answers
121 views

Software/scripts to calculate Frontal Area Index (λF)?

Maybe you know some software/scripts to calculate Frontal Area Index (λF)? This article (page 2) describes that index. For now I have not found any software or script that can calculate that (even ...
1
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0answers
609 views

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

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 ...
3
votes
2answers
384 views

Select polygons that do not intersect any other polygon using QGIS, GRASS, SAGA or R

I would like to select the polygons of the layer below that do not intersect with any other polygon (within the same layer). How can I do this using QGIS, GRASS, SAGA or R?
2
votes
2answers
435 views

Create a common scale for different raster layers in GRASS, SAGA or QGIS

I have a number of layers that represent the temperature variability of the water in a lake. They have been generated trough interpolation and have different values as they represent temperatures ...
1
vote
0answers
242 views

What steps does SAGA GIS take when calculating Topographic Wetness, specifically when handling depression filled (by ArcMap) DEM

I am a grad student involved with hydrological modeling. In the model I work on, we are calculating the Topographic Index (TI; without transmissivity - or set to 1) using Quinn's MFD algorithm. We do ...
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0answers
126 views

Is the SAGA tool Basic terrain analysis included in Processing?

I can't find the saga tool Basic terrain analysis in the Sextante/processing toolbox. Is this not included or is there a chance to install it?
1
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2answers
543 views

Missing Dependency in SAGA. Orfeo Toolbox does not work

Hej guys, I am trying to perforem segmentation from Orfeo Toolbox (QGIS last version 2.2), whenever I try to use the toolbox, I get the following message: Oooops! The following output layers could ...
1
vote
2answers
672 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
5
votes
1answer
6k views

Calculating Topographic Wetness Index (choosing from different algorithms)

Topographic Wetness Index can be expressed as Ln(a/tanB) based on the idea of Beven and Kirkby (1979) where a is the spesific catchment area (a=A/L, catchment area (A)divided by contour ...
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0answers
186 views

Defining the boundary of a catchment area

I digitized contour lines from topographic maps and created a DEM. With the DEM, I estimated the boundary of a catchment area. Estimated positional accuracy of topographic maps is RMSE = 65 m, with a ...
1
vote
2answers
493 views

How to show cell values of raster in ArcGIS

I would like to know if it is possible to display a raster cell value in the center of a cell with ArcGIS in the same way that SAGA-GIS does when you zoom in.
3
votes
2answers
344 views

Merging DEMs of different grid size

I'm trying to merge two grids with different cell size. One has a cell size of 10m and the other 50m. The 10m one covers a subarea of the 50m one. I know that the most accurate one is the 10m one and ...
3
votes
0answers
917 views

QGIS cannot open output layers

I have problem with QGIS 2.0.1. Everytime I run tool from SAGA or GRASS, I get exactly the same error, for example: Oooops! The following output layers could not be open Channel Network: ...
2
votes
0answers
175 views

Extra row and column in a raster after GDAL grid import

I'm exporting an ESRI grid to TIFF format and after that I'm reading this exported raster file into SAGA GIS. However when Saga reads this file in there appears to be an additional row and column in ...
7
votes
3answers
2k views

How to configure QGIS and SAGA on Ubuntu (12.04 and others)?

During the past weeks, I have tried QGIS to recognize SAGA via the processing toolbox, both being installed from the ubuntugis-unstable repository. I have tried this on several virtual ubuntu ...
2
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2answers
480 views

Enabling SAGA in QGIS

A similiar question has been asked recently, however I have some specific queries and process I have tried which are probably better in its own thread for clarity. Hope this is ok. See link to recent ...
1
vote
1answer
649 views

How to make GRASS and SAGA tools capable to use in QGIS?

I installed QGIS, GRASS and GDAL by OSGeo4w package, and as I finish the installation, I want to use GRASS tool, I face this problem: But I already installed GRASS and SAGA, how to make those tools ...
2
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0answers
79 views

Re-projecting WGS84 to OSGB in SAGAGIS

I took some points with a GPS, and I'm trying to convert from GCS to OSGB 1936 British National Grid in SAGAGIS. I'm working with a shapefile. To reproject the vector layer to the OSGB projection I ...
1
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2answers
1k 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
1answer
363 views

Apply r.neighbours or Neighbourhood analysis (LecoS plugin for QGIS) to 3000 rasters

I need to apply r.neighbours or Neighbourhood analysis (QGIS plugin LecoS (or equivalent) to 3000 rasters and define a neighbourhood of 5 x 5 and calculate the mean. I suppose I need to create a ...
1
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0answers
78 views

MSHP file from SAGA tough to delete

After running a SAGA line dissolve process in QGIS, an MSHP file is created (amongst other things). Fine by me, though I'm not sure what it's used for (metadata in XML format?). Problem is that it ...
0
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0answers
446 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: ...
8
votes
1answer
407 views

Where is this raster offset being introduced in the QGIS processing toolbox?

I'm using the (awesome!) processing toolbox in QGIS 2.0 to reclassify some NoData values in a raster from -9999 to 0, but at some point in the process there's an offset of about 0.2 degrees being ...
6
votes
5answers
5k views

How to set all pixels with value <= 0 to “nodata” in DEM raster?

I have a DEM raster with pixel values between about 3000 and -0.0003. I need to set all pixel with a value of 0 and smaler (<=0) to "nodata" (for later raster calculations and to reduce the ...
3
votes
1answer
830 views

How to build a confusion matrix for image classification using SAGA or QGIS?

I did a supervised classification of a Landsat image subset using my training data polygons. I used SAGA GIS for that and everything worked out fine. Now I am stuck since I have no clue how to ...
2
votes
0answers
735 views

Kriging with SAGA and QGIS [duplicate]

I have the "processing" toolbox installed on QGIS2 and it would appear to give me access to the SAGA variogram tools and and kriging tools. What I am missing and what I can't find via Google either, ...
4
votes
1answer
326 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 ...
3
votes
3answers
790 views

How to calculate peaks in a DEM

How could I extract all peaks from a DEM (large mountainous area)? Peak means something like: a pixel which is sourrounded by other pixels with smaler elevation numbers in a area arround the ...
1
vote
1answer
446 views

SAGA_CMD batch processing

I am trying to use SAGA to triangulate a set of .las files I have. I have tiled them using lastools, since the single file was too big for my computer to handle. I wonder, can I use the saga_cmd ...
1
vote
1answer
186 views

What is the best way to display point data (with standard deviation) using QGIS/SAGA/Manifold? [closed]

I would like to display point data values (indicating biomass at a point) but also to show the standard deviation value for each point. What would be the best method to do this in QGIS (I'm a basic ...
2
votes
0answers
383 views

Watershed Segmentation SAGA-GIS

I'm trying to segment a topographic map to vectorize it. I'm using the watershed algorithm of SAGA-GIS. It's working fine with polygons, but with roads or contour lines is not working properly. Here ...
6
votes
2answers
684 views

How to de-noise a DSM

I have created a DEM, DSM, and nDSM from a LiDAR Point Cloud using SAGA-GIS. I extracted the appropriate returns from the point cloud, then converted to grid, and then closed gaps to fill in any ...
1
vote
0answers
45 views

problem on loading kriging outputs [duplicate]

My problem is the following: everytime i run ordinary kriging or other interpolation techniques i obtain this error message from QGIS Notice that these are the details for SAGA I would like a ...
2
votes
3answers
854 views

how to decrease Raster size without altering cell size?

Is there a way to decrease the size of a raster image without decreasing cell size or quality? I´m using ArcInfo but also have Saga-Gis or FME. I could abviously change an 8bit raster to a 1bit ...
0
votes
1answer
1k views

Calculating longest flow path and avg. slopes for catchments with qgis?

I am a hydrologist and their are 2 important pieces of information I need for modeling. I need to know the longest flow path for each sub catchment in my area of interest and I need to know the ...
9
votes
1answer
1k views

Import GRASS and SAGA modules to python script

I'm new at this. I am "building" a python plugin for qgis and I want to import modules from GRASS and SAGA but I don't understand how to do it. The plugin I want to import is Kriging interpolation ...
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0answers
381 views

Saga Reclassify grid problem

I am using Qgis 2.1 ver. 5f5cd4c (64 bit version on win7 64) OSGeo installed. I was trying to reclassify a DEM in EPSG:32614. I used the SAGA's Reclassify algorithm in the processing toolbox. I ...
0
votes
1answer
492 views

problem in loading outputs from processing tool (sextante) [duplicate]

hopefully some of you have got an answer to what happens to me when i run (so far) all the processing tools for carrying out raster analyses. This is the type of message i receive from QGIS (2.0.1 ...
2
votes
1answer
596 views

Automating non-trivial workflow in SAGA-GIS

My problem: I have two DEMs, one rectangular and containing the other. Both are given in grid formats and the outer one has gridsize 50m, the inner one 10m. I want to 'embed' the smaller one in the ...
0
votes
1answer
323 views

Variogram Software

I would like to know wich software are suitable to create Variograms and to know sill, nugget and range easily. I would prefer if this software could run in Linux. I've tried SAGA but lacks a lot ...