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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votes
1answer
40 views

SAGA library is not visible in Processing Toolbox

The screenshot of Options > Processing I have SAGA plugin activated in my QGIS 3.8 on a Ubuntu 18 LTS machine. However, it does not show up in my Processing Toolbox. Could anyone help me solve ...
2
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0answers
802 views

Watershed Segmentation in SAGA-GIS [closed]

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 ...
1
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1answer
394 views

“Cross-classification and tabulation” tool is not outputting a table

In QGIS3 I’m trying to use SAGA’s "Cross-classification and tabulation” tool from the processing toolbox, and based on the documentation (http://www.saga-gis.org/saga_tool_doc/6.3.0/grid_analysis_13....
3
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1answer
242 views

Sentinel-1 SAR image is displayed upside down

I am looking at Sentinel-1 SAR image downloaded from ESA Copernicus - dhus location around south of Tokyo, Japan. File format is GeoTIFF. It looks good in QGIS. However, if I use SAGA, or SNAP, or ...
1
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1answer
65 views

Adding two rasters in modeller

I'm trying to build a process model which uses a series of raster operations - Rasterize, Proximity, Raster Calculator. However, I couldn't seem to add two consecutive raster calculator processes. ...
3
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2answers
839 views

QGIS: Saga Channel network: how to prepare SRTM data

I am trying to use the Saga toolbox (2.2.3) in QGIS (2.18) to create a channel network from SRTM data using this tutorial 1. It works, but the result I get when using the DEM that comes with the ...
0
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1answer
199 views

Unable to perform SAGA point snapping to line on Win and Mac

I have been trying to snap points from a shapefile to a line feature from another shapefile. However, each time I do this, I get the following error(s) (depending upon the OS used): (For OSX El ...
3
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2answers
89 views

Is there an equivalent to “keep inner boundaries” in QGIS 3?

At QGIS 3.4.7, I have some polygons that are overlapped and I use Polygon dissolver (by attribute) from SAGA to dissolve then and I check the option "keep inner boundaries", but this tool takes too ...
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0answers
19 views

Topographic Wettness Index for ecology; SAGA; usage of “sink route” for flow accumulation

The Goal is to Create a Topographic Wetness Index for ecological Studies. Saga-GIS 7.3.0 General Approach for TWI(Kopecky) calculate slope from original DEM (no filled sinks) prepare DEM with ...
4
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1answer
674 views

Debugging errors of SAGA interpolation algorithms in QGIS Processing?

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter what technique I use I end with the following errors. As stated in the OGR tab QGIS 2.0 is unable to open a ...
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0answers
9 views

How to select bands in saga_cmd?

I want to calculate NDVI for a BGRN tiff file using saga_cmd http://www.saga-gis.org/saga_tool_doc/7.3.0/imagery_tools_1.html The problem is that I have to specify the RED and the NIR inputs. I would ...
3
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1answer
2k views

Building confusion matrix for image classification using SAGA?

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 ...
1
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0answers
34 views

Use of QGIS/GRASS/SAGA procedures on Geometry Generator

Im new at QGIS, started 2 weeks ago. I'm trying to automatize the display of a map and get rid of some "duplicated" layers and all the extra work. I need to know if SAGA's dissolve can be used in the ...
4
votes
1answer
417 views

Writing SAGA_CMD command line formatting

I am trying to use SAGA_cmd to write a script that does the following: The united 1) Reads a series TIFF files I have in the work folder; 2) Runs a segmentation on the TIFF files on each respective ...
3
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1answer
1k 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 ...
1
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0answers
49 views

Classification result from SAGA GIS shifted by 5 meters if used in ArcMap?

I use a band composite of 10 Sentinel-2 bands for my classifications. If I use the same composite in SAGA to make a classification this classification result is shifted by 5 meters to the left and to ...
1
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1answer
84 views

Exporting landcover clasiffication from ENVI to SAGA

I have basic knowledge in remote sensing and GIS. I have generated landcover map in ENVI 4.7. How can I transfer or Export/Import this into SAGA so that I perform other functions in SAGA. I want to ...
16
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4answers
5k views

Manually correcting raster DEM (OpenSource)?

Is it possible, to correct a raster DEM by changeing the raster-cell-values manually, like by "painting"? My DEM (ASTER) have one small error where the elevation is about 300m below the actual ...
0
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1answer
34 views

What are the formulas used in SAGA Ordinary Kriging?

can some one name the formulas avaible in the Ordinary Kriging Modul of SAGA: What ist the exponential, spherical, Gaussian-Model, etc.?
0
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0answers
37 views

Least Cost Path in QGIS: Plugin or SAGA or GRASS?

I downloaded a SRTM file and followed this tutorial and now I have a hillshade layer and a color layer. It looks like this. I want to calculate the least cost path between p1 and p2. But I'm not ...
2
votes
1answer
213 views

How to close open files after processing.runlag() command (Qgis: Error No 24)

I'm creating a pyqgis script. In this script I use the processing.runalg command several times. The problem is that these processes are within a for loop. After several iterations, the error number 24 ...
2
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1answer
32 views

What unit is the topographic openness (SAGA GIS)?

The SAGA GIS tool "Topographic Openness" calculates the positive and negative topographic openness and is based on Yokoyama et al. (2002) who do not specifically say the unit of the final result. They ...
1
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1answer
49 views

Clipping converts multiband to single band

I have a multiband raster image. I am trying to extract the AOI by using "Clip raster with polygon" option in SAGA module. The process clips the raster to the exact size of the polygon but the ...
9
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1answer
16k 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 specific catchment area (a=A/L, catchment area (A)divided by contour length(...
4
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1answer
2k 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 (...
2
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0answers
45 views

Saga GIS Snap Points to Lines tool doesn't produce required results

I have two sets of data that I'm using. Points extracted from a .csv file and a road network from an ESRI .shp file (both of which I've included here: https://send.firefox.com/download/...
3
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1answer
52 views

What is the purpose of these SAGA raster mosaic parameters?

BACKGROUND: Using QGIS 3.8.0 Processing > Toolbox > SAGA > Raster tools > Mosaic raster layers, I do not understand the purpose of the Match and Fit parameters. Here's a screenshot of the Match ...
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0answers
44 views

QGIS SAGA Overland flow distance to channel network not working

I am trying to run the QGIS SAGA tool "Overland flow distance to channel network" with a DEM and the channel network raster developed from this same DEM using the SAGA tool "Channel network." However, ...
18
votes
1answer
569 views

Determining flow path length in QGIS?

I need help with qgis flow path length. I try to run the program and when I run the program I get a raster with 0 values, as input I'm using filled raster, I don't now if I'm doing something wrong or ...
32
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5answers
56k views

Splitting shapefile into separate files for each feature using QGIS/GDAL/SAGA?

I have a polyline shapefile with about 20 kinds of roads. I would like to know how can I create automatically a vector file for each one. I am aware of how to do it using ArcGIS for Desktop - see ...
2
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0answers
470 views

SAGA not working within sextante when QGIS processing installed in Ubuntu? [closed]

Recently i decided to start working in Ubuntu (version 14.04). My first step was to add the ubuntugis-unestable repository, and then proceed to install SAGA, GRASS, OTB, QGIS and the bindings between ...
7
votes
1answer
2k views

Is there any way to include “universal” style/symbology in GeoPackage?

I am just playing with the GeoPackage format in QGIS. In QGIS it works nice with the style saved from QGIS but if I load it for example in SAGA the style is not applied. Is there any way to include ...
3
votes
1answer
87 views

Using SAGA GIS 7.X modules in QGIS

Is it possible (and how) to use the SAGA GIS 7.x modules in QGIS (as well as for GRASS GIS)?
1
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1answer
65 views

Error creating DEM with Nearest Neighbour tool in QGIS?

I have an issue when I am creating a DEM with the tool natural neighbour on QGIS. When I extract my data directly on Qgis I have no issue creating a DEM. My points are coming from different sources ...
1
vote
3answers
133 views

Converting raster pixels to vector cells?

Is there any way to convert raster pixels to vector cells? I mean each pixel to a polygon. I tried the SAGA tool 'Raster values to points' by choosing cells option instead of nodes option. As a ...
1
vote
0answers
98 views

SAGA: could not initialize data objects (QGIS 3.6, Mac 10.14)

I was trying to generate a catchment area from a DEM and got the error message: The following layers were not correctly generated.<ul><li>/var/folders/ft/rbsnpzy96r76t8rkj5fdtzc40000gn/T/...
1
vote
1answer
21 views

Using Formal Class RasterLayer as RSAGA input and otput

Is there a way to use the data from the R global environment object as input for an rsaga.geoprocessor alghoritm? And if yes, can be the output also saved as a same object? I am writing chain ...
2
votes
1answer
122 views

SAGA landform classification crashing on MAC, Windows, standalone or with QGIS

I am trying to apply the "TPI-based landform classification" algorithm from SAGA. Originally in QGIS 2.14, on a MAC, then on windows and with SAGA standalone, but it quickly saturates memory/CPU and ...
1
vote
1answer
152 views

Large Scale Watershed Delineation

Using QGIS,I attempted Africa's watershed delineation taking the following steps: Downloaded DEM from earthexplorer USGS (GTOPO30) Created a mosaic of the downloaded DEM Reprojected the mosaic ...
2
votes
0answers
38 views

VRM tool QGIS error generating layer

I am trying to use the VRM tool in QGIS of the SAGA package. Every time I get an error message: layers could not be generated. I tried different input rasters (DEM and DTM) and kept other settings ...
3
votes
1answer
283 views

Choosing parameters for SAGA Wetness Index?

I've been working with SAGA GIS to calculate the Topographic Wetness Index of an alpine catchment. I am using the tool Terrain analysis > Hydrology > SAGA Wetness Index because, compared to ...
2
votes
0answers
60 views

Inaccurate raster values from “SAGA Extract Raster Values to Points”

I am perplexed by the results generated by the SAGA 2.3.1 Extract Values to Points tool in QGIS 2.18. I am working with Vegetation Index raster layers, which means the values are between -1 and 1. ...
1
vote
0answers
32 views

No SAGA folder in processing options dialog box

I am using QGIS 2.18. I am facing this error while using EasyAHP: "The error occured during calculation. Please make sure that Processing Toolbox's SAGA provider is installed." But, I guess the ...
0
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0answers
68 views

Easy AHP returns error because it can not find the SAGA 2.3.2 folder

When I try to complete the AHP in QGIS 2.18.27 using easy_AHP, the plugin responds: although the SAGA tools are working perfectly by the Processing Toolbox. The SAGA configuration options in QGIS ...
1
vote
1answer
105 views

Raster Volume Returning Wrong Volume

I have a clipped surface using Washington State Plane North (feet) added to a QGIS project using the same CRS. I am trying to calculate the area under this surface (a dirt pile) using SAGA Raster ...
3
votes
1answer
51 views

Cheapest path through polygons and lines from point to point

I want to find the cheapest path or the least cost path from one point to another point. The points are part of a vector map and do not lie on a network. All features being part of the map have ...
1
vote
1answer
112 views

Analytical hierarchy process tool - SAGA. How to configure Pairwise comparisons table?

What is the configuration and extension (.txt, .csv ...) of the Pairwise comparisons table file requested by the SAGA AHP tool- Analytical Hierarchy Process - in QGIS? Are there examples of ...
3
votes
0answers
71 views

Extracting GeoTIFF colours and adding to equal geometry shapefile

I have the following map in .png-format that I would like to replicate, but I cannot obtain the original data. The map shows the current water supply vulnerability for local municipalities in South ...
2
votes
2answers
4k views

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

I have 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 temperature ...
0
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1answer
113 views

QGIS 3.4 Stream delineation problem, lines running too far into ocean

I am using QGIS 3.4.4 Madeira version trying to delineate the stream and catchment areas of a small Bay in Honduras based on the technique of Hanz van der kwast tutorial "Stream and Catchment ...