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

I am a hydrologist and there 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 ...
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10k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
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22 views

Importing TIFF to SAGA

I'm trying to import a large GeoTIFF (~1.2 GB) into SAGA GIS for processing as a grid using Import/Export - GDAL/OGR -> GDAL: Import Raster, but it keeps crashing. I'm using the 32bit OSGEO4W SAGA ...
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4answers
548 views

Generating equal sized polygons along line with PyQGIS?

I would like to create polygons along a line to use them for AtlasCreator in a next step. ArcMap has a tool called Strip Map Index Features. With this tool I can choose the height and width of my ...
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41 views

Solar radiation flux at 5 minute interval using GRASS GIS r.sun

I have been trying to estimate instantaneous total solar irradiance(w/m2) at five minute interval for a day (eg. 21 sept). I can do this in SAGA GIS by using "moment, mode 1" and running the solar ...
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26 views

How to delete by attribute from shapefile in SAGA command

I have lot of shapefiles to erase polygons with same attribute form them. It is usually an easy task when do manually, but how can I use SAGA-GIS command? Any help?
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3k views

Performing Ordinary Kriging in SAGA via QGIS SEXTANTE Plug-in?

I'm trying to learn how to apply the kriging analysis in QGIS using the SEXTANTE plug-in and SAGA tools. It appears that I have my SEXTANTE and SAGA folders configured properly according to the user ...
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326 views

QGIS 2.12 & Ubuntu 14.04 SAGA installation not found

Installing QGIS 2.12 on Ubuntu 14.04 from the debian trusty ppa. Upon opening QGIS I notice the following error under the Processing tab: Problem with SAGA installation: SAGA was not found or is not ...
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15 views

Processing toolbox on Google Cloud compute engine

I used to utilize the QGIS python console to do GIS batch operations on my local machine. Computation times are rapidly increasing and I'm switching to a virtual machine solution in the cloud. How ...
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29 views

Where does the output of a grid volume run in the Saga tool/ Qgis end up?

I have tried to do a grid volume run with the Saga grid calculus - grid volume function. After the run the window closes and nothing seems to happen, no message, no new layer or information appear. I ...
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105 views

strange output from RSAGA topographic wetness index

I am trying to generate a topographic wetness index raster with the RSAGA package in R. The output I am able to generate does not make sense to me, as it has a large number of NA cells and I wonder if ...
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15 views

How to chain several conditions in SAGA raster calculator

Is there a way to use an AND statement within SAGA raster calculator expression to include several conditions in the same operation? I have 3 rasters, the statment should be: If (A = 0 and B = ...
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1answer
60 views

SAGA tools in QGIS only allow save as .sdat file?

I'm just beginning to learn how to use SAGA 2.1.2 tools within QGIS 2.12.1 on a Windows 7 64 bit computer by working through exercises in Mastering QGIS by Menke et al. ...
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2answers
686 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 ...
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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 ...
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3answers
76 views

Dissolve overlapping polygons in SAGA

I've got the following (2D!) situation of overlapping polygons: I would like to have the polygon border dissolved such that I have only one polygon left. I thought this was a definitive case for ...
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3answers
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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 ...
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138 views

Least cost path between various points QGIS

Is there an easy way to find the least cost path (LCP) between various points in an open source GIS? This question has actually already been asked here: How to find a least cost path through several ...
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Raster calculators in SAGA return incorrect results

Here's a sample of my dataset (one cell) with 28 different raster values, representing 28 individual Float32 rasters with identical parameters. 0.0000264434, 0.0049953502, 0.0007529828, ...
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SAGA-Inverse Distance Weighting in QGIS - How to Set Minimum Number of Points?

I am analyzing a postGIS point dataset in QGIS version 2.8.2, about 200k features total. To calculate weighted average values I am using the Inverse Distance Weighted interpolation technique. However, ...
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597 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) ...
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46 views

Check QGIS processing Saga version from a plugin

I am writing a QGIS plugin using SAGA by Processing. Is is possible to test whether SAGA is installed and which version is on? For GDAL, it's OK with: processing.tools.raster.gdal.__version__
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654 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 ...
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1answer
144 views

No Saga in QGIS 2.12

After installed QGIS 2.12 I don't have SAGA in Processing Toolbox anymore and I need it bad. Am I blind, can't find it or something went wrong? Any suggestions please? My OS is Win 7 64 bit.
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SAGA Tool in QGIS Error: Load table: Proj.4-WKT Dictionary… failed

I have some problems with running SAGA tools in QGIS. I've downloaded and installed the software via the OSGeo4W Installer. It downloaded QGIS 2.12 and Saga 2.1.2. I wanted to use the Tool "Shapes To ...
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469 views

Extract many or clustered cells attributes around points using SAGA GIS?

My question is similar to Extract raster values at points, but perhaps more complex. How to extract the attributes of clustered cells around a point/points? For example, I have many vegetation ...
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2answers
191 views

Why is SAGA from the Processing Plugin not recognised?

Similar to this post: SAGA algorithms don't work in QGIS 2.8 except the fact that SAGA does not appear at all in the Processing Toolbox: As a check, I used the Python Console with the following ...
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562 views

QGis Grid statistics for polygons error - Module caused access violation!

I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log ...
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1answer
55 views

QGIS 2.12 Lyon - SAGA dissolve tool keep only one column of data

I have installed QGIS 2.12 Lyon and I need to dissolve multiple polygons according to one column in the dbf file (my layer is a shape file). I have used SAGA "Polygon dissolve by attribute" algorithm ...
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1answer
125 views

Saga tools missing in QGIS [closed]

First things first! I am using Ubuntu Mate on 15.04. I installed Qgis and SAGA via the http://ppa.launchpad.net/ubuntugis/ubuntugis-unstable/ubuntu packages. So I use QGIS 2.12 and SAGA 2.1.4. I ...
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59 views

Is it possible to inject a value into an algorithm text setting in QGIS Processing Model?

I have a SAGA Raster Calculator algorithm inside a model that I'm building. For the formula, I'm using the function (g1>20)*1 to give me a binary raster output. This categorises pixels to ...
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48 views

Improve tree extraction method

I want to extract trees from a given normalized Digital Surface Model (nDSM) in SAGA GIS. My workflow is the following: Applying a Gaussian Filter to the nDSM with search radius with standard ...
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75 views

SAGA hydrological analysis in QGIS 2.8 on Mac

I am running QGIS 2.8 on a Mac machine and I want to calculate the catchment area using SAGA - Catchment Area. It starts running but after a while when QGIS wants to open the generated files there is ...
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39 views

Hydrology Analysis via SAGA - what is the unit? [closed]

I did a couple of analysis via SAGA about an area in Iceland...I've never worked with SAGA before, could anyone tell me what Units the numbers in the legends for "Catchment Area Recursive" and ...
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1answer
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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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1answer
4k views

Calculate Topographic wetness index in SAGA

i am currently working on a project which involves the quantification of the wetness in certain areas. However it produces quite different results from what i expected. I'll describe the steps i have ...
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1answer
447 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 ...
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275 views

Does Processing plugin v2.10.1 not recognise SAGA?

Version 2.9.3 of the Processing plugin works fine, I can run the SAGA tools successfully. Updating the Processing plugin to version 2.10.1 results in SAGA disappearing entirely from the toolbox. The ...
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How is “flat” defined in SAGA

SAGA has a feature that determines flats. Does anybody know how they define a flat? If I start with a raster, each pixel is flat - so it has to be more sophisticated than that. I would like to be ...
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43 views

Error when using SAGA's “topographic correction” algorithm in QGIS

I'm trying to do topographic correction of Landsat images using SAGA's "topographic correction" algorithm from QGIS' processing toolbox. I was able to do it using Minnaert Correction with slope and ...
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1answer
231 views

saga_gui.exe identified as malware by antivirus when downloaded from OSGeo4W [closed]

I downloaded QGIS 2.6.1-2 (Brighton) yesterday from OSGeo4W-setup-x86.exe using the advanced installation option on a machine running on windows 7 professional. The download worked Ok except for saga ...
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61 views

Delineate watershed using manual points in RSAGA

I'm currently trying for an automated solution to delineate watersheds within a large basin. I have a collection of locations (X,Y coords) for various tributaries reaching a larger river, and the ...
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0answers
7 views

Sky View Factor of building roofs => Vector algorithm [duplicate]

I'm currently working on a project in which I'm trying to assess the SkyViewFactor of a given roof using building vector data. I've already managed to build a process based on vector rasterization ...
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2k views

How to implement viewshed calculation?

I'm looking for a way to implement visibility (aka viewshed). I found a previous GIS SE question that suggested a few GIS applications (not what I need - I'm trying to embed the calculations), and ...
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89 views

Trouble with kernel density estimation

I have been trying to find out how to make the SAGA and GRASS kernel density tools work in QGIS 2.8. I have had a lot of trouble trying to get them to work as they produce useless results seen below. ...
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1answer
212 views

SAGA tool 'Relative Heights and Slope Positions' - What do results tell me?

I am currently trying to get in morphometry, using the SRTM 30m DEM. I was recommended to test the SAGA mudule 'Relative Heights and Slope Positions' ...
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1answer
50 views

osgeo4w not installing processing tools in QGIS toobox. [duplicate]

I have uninstalled and reinstalled QGIS several times from the OSGeo4W application. I have done this with no problem on several other times, but now I cannot get the tools to load. Most of the help ...
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51 views

NDVI Workflow Problems, Red Channel Seems High Causing Low NDVI value?

I did some searching but nothing came up around this. I'm trying to verify a workflow from images to an NDVI to verify I have a basic workflow correct. Process images example dataset through ...
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2answers
118 views

How to sum values of overlapped pixels in thousands of rasters layers and clip it using a polygon in QGIS?

I have a lot of rasters files (more than 6000), each one represents the presence and absence of a species (1 for presence and NoData for absence). The set of rasters covers the whole Latin America ...
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186 views

SAGA version with QGIS 2.10

I want to know which version of SAGA is used with QGIS 2.10. I developed a standalone application which uses QGIS inside. I have problems using SAGA algorithms. SAGA is well installed but I found that ...