Questions tagged [saga]

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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3
votes
0answers
151 views

Why is 'Line Dissolve' producing different output than 'Dissolve' from Ftools?

I'm curious if anyone can explain the strange effects I'm seeing from the SAGA 'Line Dissolve' tool. I have a ton of line features that had previously been 'exploded' (which is a necessary step), and ...
6
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1answer
715 views

SAGA GIS raster calculator - QGIS scripting gt expression

I am trying to perform a simple raster calculator that takes input rasters and outputs a new raster with a constant value where values exceed a specified number in the input. This is part of of a ...
1
vote
1answer
165 views

Terrain analysis

I tried running ArcSaga Morphometry python based tool for slope,aspect and curvature but it failed what could be the problem? ......t" # # # # # # # # # # "9 parameter 2nd order polynom (Zevenbergen &...
8
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2answers
2k views

SAGA algorithms not working on Qgis 2.18 on Mac OSX

Since last update to Qgis 2.18 from 2.14, I'm unable to successfully run SAGA algorithms (Mac OSX Yosemite). No matters if it is vector- or raster-oriented algorithm, the algorithm stops at this point ...
2
votes
1answer
369 views

Why does Accumulated cost fail with 'QgsVectorLayer' object has no attribute 'bandCount'?

When using the function Accumulated cost (isotropic) from the SAGA algorithms in QGIS i get the following error message: An error has occurred while executing Python code: AttributeError: '...
3
votes
1answer
233 views

How calculate relative heights in SAGA?

I've calculated relative heights in ArcGIS, now I'd like to calculate relative heights (range between maximum and minimum cell value in window 3x3) in SAGA. It's important that I don't want ...
2
votes
1answer
874 views

How SAGA calulates Convergence Index

I have calculated convergence index on my DEM with SAGA. Output results seems to be ok (values in range -100;100), but I don't understand how it works. Here is some sample data from my DEM: I know ...
2
votes
1answer
330 views

Calculating curvature in SAGA?

I have calculated curvature using ArcGIS (curvature) and SAGA (Slope, Aspect, Curvature; based on 9 parameter 2nd order polynom (Zevenbergen & Thorne 1987) method), however, the output rasters are ...
8
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4answers
2k views

How to change SAGA path in QGIS 2.18 Standalone

I have installed QGIS 2.18 Standalone (64 Bit) with SAGA GIS (2.1.2) and GRASS GIS 7. Afterwards I have installed the newest SAGA GIS 3.0.0. I want to change the SAGA folder in the processing options,...
1
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1answer
134 views

Calculating land sea area ratio in a portion of raster map in QGIS

I wanted to know how can I calculate land/sea area ratio in a portion of raster map (attached in the mail) Till now i had this raster map that i converted in to vector by the option raster>>conversion>...
5
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1answer
311 views

Getting Output names of Processing algorithms via PyQGIS

Calling the results of Processing algorithms in order to plot them to the screen differs depending on the provider used. An example with QGIS provider: tmpggis = processing.runalg("qgis:...
2
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1answer
423 views

SAGA Upslope Area Calculation from Vector Point Layer resolves in no output and no error message

I'm using the SAGA Upslope Area algorithm within pyqgis, but i'm stranded, since my script doesn't create any output at all. I'm trying to use geometry from points in a vector point layer as input x ...
2
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0answers
217 views

How is ray tracing different from ambient occlusion when hillshading with SAGA?

SAGA offers both raytracing and ambient occlusion in its Analytical Hillshading module, but doesn't explain how these modes differ. Is one significantly more expensive in computation, and is the ...
4
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1answer
147 views

SAGA GIS segfaults on launch

I'm having problems with SAGA GIS. It segfaults on launch, either from the command line or when called from QGIS. If I run saga_cmd using gdb, I get this error:- (gdb) run Starting program: /usr/...
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0answers
263 views

SAGA_CMD: select polygon features of one shapefile and save in new shape files [closed]

I want to use saga_cmd to select from a shapefile only the shapes, which have a certain area size and store this selection into a new shapefile. I'm using the following command to filter via the ...
1
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0answers
176 views

QGIS for mac acting strange after upgrade to 2.16

I'm running OSX 10.10.5 and just upgraded QGIS from 2.14 to 2.16. 1st. the installed GDAL 2.1 wasn't registering when using gdalinfo --version. It still showed 1.11... So I used MAPBOX GUIDE to get ...
4
votes
2answers
511 views

Why does saving a big Shapefile take so long?

When trying to save a large (281250 shapes), yet fairly simple shapefile (all shapes are rectangles with 5 attributes) from QGIS, it was still trying to save for over 2 to 3 hours before I killed it. ...
2
votes
1answer
730 views

Problem with Saga in Qgis 2.14.6

I am trying to run saga tool however I always received errors. I am using Ubuntu Xenial Xerus (16.04), Qgis 2.14.6 and Saga 2.2.7. Log (OGR) error: 2016-09-07T15:22:28 1 Data source is invalid () ...
2
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0answers
155 views

QGIS SAGA Raster Calculator returns incorrect results

The SAGA Raster Calculator within QGIS produces wrong results probably due to interpolation but works corretly withion SAGA itself. The problem has been discussed here before but sofar I have not ...
3
votes
2answers
668 views

“Object based Image Segmentation” and some options are absent in SAGA

Although I have the latest version of SAGA, "Object based Image Segmentation" and some options do not appear when I click on "Geoprocessing>Imagery> Segmentation>? " Why are they absent?
2
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0answers
51 views

Warning from SAGA when doing Topographic Corrections?

I am trying to use SAGA for topographic corrections for the first time, however I am getting a warning that says: data not in the same grid Can any one suggest ways of formatting the data (DEM and ...
3
votes
2answers
120 views

Preserving Projection on SAGA-produced Rasters

I perform a fair amount of hydrological processing in QGIS and rely on SAGA's Topographical Wetness Index and slope-derived functions. In order to use them, SAGA demands that input rasters are warped ...
4
votes
2answers
914 views

QGIS: SAGA-GIS module “Add raster value to point” Error: unknown option 'INTERPOL'

I encountered an error while using the "Add raster value to point" SAGA-GIS module in QGIS (2.16) to retrieve altitude values from a raster DEM previously interpolated from TIN points (as vector ...
3
votes
2answers
2k views

Problems with Saga integration in QGIS 2.14.4 LTR

I've installed QGIS 2.14.4 LTR (32 bit) on my WIN7 64bit system. But I believe something is wrong with the "Processing" plugin as many of the features were missing from what I've used earlier. My QGIS ...
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0answers
24 views

Tiger WOIS Could not open workflow

Recently I have been trying to use the TIGER WOIS package which looks really useful. I'm trying to use the Flood mapping tool with Sentinel-I data, but I encountered a problem right away. In the ...
-1
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1answer
212 views

SAGA-GIS (2.3.1) fatal error during compilation (Ubuntu 16.04) hdf5.h not found in /usr/include/vigra/ subdir

OS : Ubuntu 16.04 Compilation using : ./configure && make I encountered a fatal error while compiling SAGA-GIS 2.3.1 : Making all in imagery_vigra make[5]: Entering directory '/home/...
2
votes
0answers
488 views

SAGA GIS work with python API error

I want to work with python API and SAGA GIS. I am very new with this work. The first step I find one module for example Slope, Aspect, Curvature and I take with right click one python script. python ...
2
votes
1answer
162 views

SAGA Raster Calculator in QGIS Graphical Modeller not subtracting [closed]

I am using QGIS 2.8.1 to build a model. All is working fine until the raster calculator input. I understand that the raster calculator in QGIS Modeller is a SAGA tool. With this, I have tried both the ...
1
vote
1answer
479 views

QGIS- extract raster information into a point return nulls

I have a 1) raster layer and a 2) point layer. I want to extract the pixel value to each point, but it is not working when using this tools (QGIS): plug-in "Point sampling tool" (the new shapefile ...
3
votes
3answers
416 views

QGIS cluster gdal Unknown option 'INTERPOL'

I am running cluster analysis from image analysis menu of saga provider in QGIS. I use the qgis GUI from processing tool box, I call saga modules. I got same error in many other algorithms. I can ...
3
votes
0answers
769 views

Error on running Saga GIS inside QGIS

I have installed QGIS (2.14.3-Essen) along with SAGA GIS (Version: 2.2.7) in Ubuntu (14.04 trusty). I am trying to fill the sinks in a DEM in QGIS processing using SAGA provider. I have used both the ...
2
votes
1answer
434 views

Where are GRID algorithms in SAGA 2.1.4?

I am a real newbie on QGIS and wanting to draw contour maps from satellite, following the youtube videos. So now I have a table with all data, and following the video, I should use the SAGA tool GRID ...
2
votes
0answers
305 views

Dissolving polygons using SAGA leaves gaps?

I am new in using GIS and I'm having some problems in properly dissolving some polygons. In particular, I have a single layer with about 3,000 polygons (protected areas), some of which overlap (the ...
2
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0answers
693 views

SAGA Merge raster layers error

I have 198 tiles of a DEM from which I want to extract contour lines, but doing the operation 198 times is ungainly. I tried SAGA's Merge raster layers, but it stops into this error: Oooops! The ...
3
votes
1answer
678 views

Failed DEM via Natural Neighbor in QGIS 2.14.2-Essen

Following the indications of Monde Geospatial (https://www.youtube.com/watch?v=bLbY3iMBW-A) I created a CSV file with the altitudinal data (Google Earth) for 2182 total points and imported it into ...
7
votes
2answers
260 views

Improve DTM under forested areas without smoothing?

I'm using a DTM retrieved from LiDAR data and I noticed that forested areas are grainy or not defined. The DTM data was retrieved from geostore.com. Here is one example: Is there any way to directly ...
2
votes
1answer
721 views

Positive Topographic Openness - do any FOSS tools (other than SAGA) provide this?

I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS) Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a ...
3
votes
0answers
344 views

Error with SAGA's Topgraphic Correction: Can't load requested DLL gdal_MrSID.dll

I am using QGIS 2.14.2, trying to perform a supervised classification on a rapideye image with the SCP plugin. To improve my classification im trying to work with the SAGA's topographic correction. I'...
3
votes
1answer
1k views

Importing raster to QGIS gives CRS undefined error

I make a raster file from LiDAR .las files in SAGA. The CRS of .las is Slovenian National Grid. Then, I export it as GeoTiff (Import/Export - GDAL/OGR - Export GeoTiff). When I import it into QGIS (...
3
votes
0answers
158 views

“Select a tool” error Saga: Accumulated cost (isotropic)

I'm trying to run Saga's accumulated cost operation in QGIS on a DEM and set of raster destination points, but keep receiving an "Error: select a tool" in the log after a failed run. There are no ...
3
votes
0answers
392 views

QGIS: How to create a crosstab using SAGA toolbox cross calssification and tabulation?

I am trying to use Cross classification and tabulation SAGA toolbox. I have a raster DEM file (14 classes) and raster file precipitation (13 classes). I want to do cross-tab - but I don't know how ...
3
votes
1answer
346 views

SAGA 2.2.5 Problem Object Based Image Segmentation

Every time I use the Object Based Image Segmentation with Landsat 8 data I get a segmentated image which looks like a spider's web. The image contains no 0 values. Anyone has a idea how to fix this?
3
votes
0answers
645 views

How to interpolate (ordinary kriging) large files with QGIS processing

I'm using the Saga ordinary kriging tool as apart of different processing models. The biggest issue I have is the very slow performance. My point shape files have mostly more than 200.00 points (some ...
2
votes
0answers
286 views

SAGA GIS Channel network crash

So, i had this very weird bug while treating my dem data lately. I used SAGA to create flows channel networks on a dem i acquired a little while ago. Preprocessed it using sink route detection and ...
2
votes
1answer
278 views

Why does SAGA raster calculator interpolate between cell values?

I have a raster layer with a series of integer values (classes) for each cell. I am trying to use the SAGA Raster Calculator module (called through QGIS) with conditional statements to reclassify each ...
4
votes
1answer
148 views

Why do I get this anomaly (vertical line) in my TWI raster?

I have derived TWI using SAGA GIS, Have a look on the center of the image, a vertical line goes through it from top to bottom. Anyone else confronted this issue?
7
votes
3answers
448 views

Using variable window (“kernel”) size for raster processing in QGIS?

I'd like to use differently sized windows as I process (a.k.a. filter) a raster, with the size varying according to latitude. There are tools that allow a user to specify custom windows (e.g., "User-...
2
votes
0answers
153 views

Mosaic overlapping, irregular raster layers produces grid of NaN

I am trying to use the SAGA - Mosaic operator in QGIS 2.14.0 to mosaic two viewshed raster outputs I have. The viewsheds are irregularly shaped and overlap considerably, thus the need for the Mosaic ...
1
vote
0answers
209 views

Georeferenced Image Overlay and export to new image

I have two Geotiffs (one satellite image, one clipped image). I want to put the clipped image over the satellite image, because it shows flow velocity from this shown glacier (see image below). I ...
4
votes
1answer
319 views

Understanding SAGA Watershed Segmentation in QGIS: Error 1?

I am trying to run a watershed segmentation using the SAGA plugin in QGIS. Unfortunately, every time I have tried to run this on a specific file QGIS freezes. The log output reports the following: ...