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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0answers
376 views

How to properly calculate annual irradiance using QGIS

I want to calculate annual irradiance for a couple of buildings to establish how much PV energy can be potentially harvested. Which algorithm You recommend for this purpose: "r.sun" from GRASS ...
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623 views

Saga 2.3.2 fill sink

I am trying to run the saga fill sinks (wang &liu) but it always results in following error "'NoneType' object has no attribute 'crs' See log for more details". I am using QGIS 2.18.12. I am ...
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1answer
117 views

PyQGIS - Saga Channelnetwork

I am trying to run this from QGIS python console to extract the channel network from the DEM, based on the catchment area: processing.runalg('saga:channelnetwork', 'C:/Data/filled.tif', None, 'C:/...
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1answer
1k views

Irradiance analysis - GRASS vs SAGA significant discrepancies

I wanted to calculate and visualize the irradiance values for a plot. Do not know why, but in my copy of QGIS 2.18.5 I am missing appropriate SAGA module in the "Terrain Analysis -> Lightning", so I ...
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1answer
562 views

Determine the flow direction from a point in a DEM [closed]

I had a quick look of the other questions about hydrology using a DEM (SAGA/ArGIS) and I guess I need to calculate something different from a traditional flow accumulation/channel network/catchment ...
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214 views

pyqgis standalone script Unable to execute algorithm Input layers do not have the same grid extent

I created a simple pyqgis standalone script and I have some errors with some datasets and I don't know why some times the script works fine and other times the script gives an error : TypeError: '...
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181 views

Topographic correction in QGIS SAGA error: Input layers do not have the same grid extent

I have sentinel-2 layer images and one TIN image. I resampled the TIN to same spatial resolution in Layer 4 (10m). Both images are in the same reference system. But when I try to perform topographic ...
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502 views

How to calculate the distances to outlet along the flow path ?

I have created these raster files for a river basin: DEM Flow Direction Flow Accumulation I like to genereate a layer how it is shown in the picture below. I need the values for the distances from ...
3
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1answer
922 views

SAGA IDW interpolation algorithm has been changed?

Yesterday, I try after a long time to make an IDW interpolation on a point layer in Qgis 2.18 with SAGA tools. I use same parameters as before on Qgis 2.14, but the result is quite different. Raster ...
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1answer
274 views

SAGA Slope Stability algorithms missing in QGIS 2.18.11

I have install QGIS 2.18.11 via OSGEO4W 64 bit (that programs and versions install with QGIS SAGA version 2.3.2 GRASS version 7.2.1). I can use SAGA algorithms without problem in QGIS using processing ...
3
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1answer
726 views

Set path to SAGA from QGIS on OSX

After a crash and subsequent reinstall I cannot access SAGA GIS in the processing toolbox, and it appears that QGIS can't find it as there is no setting for the path. How can I set the path from ...
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1k views

QGIS-SAGA Add Raster Values To Points How to apply update

I have a lattice of points. I have a surface model. Both layers share a CRS. I am trying to populate the point file with the values from the underlying raster using the SAGA tool Add Raster Values ...
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1answer
956 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 ...
3
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1answer
470 views

Using the field calculator in SAGA-GIS

I am working with SAGA-GIS and need to create an euclidean allocation raster. For this, I need to first create an integer raster with values for certain areas. This integer raster shall be based on a ...
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0answers
349 views

Using SAGA and GRASS on macOS Sierra?

I am trying to run QGIS 2.18.13 on Mac OS Sierra (10.12.4), but I'm having problems with SAGA and GRASS, at least from processing. Here's what I did: Installed QGIS from brew, but ended up having ...
4
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2answers
11k views

How to delineate watersheds in QGIS?

I am using qgis 2.14.17 with ubuntu16. Having as input data a DEM of the region and a river network. In the manual of qgis they suggest to use a toll of qgis: Catchment area (Parallel); I dont have ...
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1answer
288 views

SAGA raster calculator, ifelse command syntax problem

I would like to combine two raster in Raster calculator of Saga. With raster calculator of QGIS , I have no problem, but with ifelse command syntax of Saga, the operation don't run. The operation is :...
2
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1answer
782 views

Error in catchment area calculation

I downloaded a DEM based on the ASTER Global Digital Elevation Model (resolution 30 m; ASTGTM2_N42W009_dem.tif) from the Earth Explorer website (https://earthexplorer.usgs.gov/). I am trying to ...
10
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2answers
13k views

How does Zonal Statistics work exactly?

I'm a bit confused on how the zonal statistics tools work in QGIS (either the 'Zonal Statistics' tool under the Raster tools from the QGIS geoalgorithms toolbox or the 'Raster statistics from polygons'...
3
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1answer
2k views

Legend of Flow Direction calculated with processing toolbox QGIS (SAGA)

I tried to figure out the legend of the output for flow direction when I use the QGIS processing toolbox function from SAGA (Channel network and drainage basin). I get a raster with values from 0 to 7....
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1answer
580 views

SAGA command line not working

I'm trying to script a reclassification using SAGA Grid_Tools-Reclassify Grid Values tool but I'm having the error: Reclassify Grid Values: could not initialize data objects. I've tried different ...
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1answer
284 views

DEM, points values and elevation to create a map of temeperature

I am using SAGA - Universal Kriging (Global) for this, but I am stucked. I have grid (.tif) for Serbia with elevation values, and .shp file with points that have mean yearly temperature. I want to ...
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0answers
522 views

SAGA Raster Mosaic Issue with output (projection/not showing)

I am trying to create a mosaic from a couple of georeferenced raster images (old aerial photos) using the SAGA mosaic raster layers function from the QGIS toolbox. Project and layers are all on the ...
6
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1answer
876 views

Delineating coastal subbasins using SAGA GIS or GRASS in QGIS?

I'm having some problems trying to delineate watersheds using the SAGA watershed delineation tools in QGIS. I have a SRTM DEM (cell size 30 m) which I set the water cells to NULL values, following ...
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0answers
220 views

Use SAGA from within QGIS on mac osx

I am trying to use SAGA from within QGIS. I can run SAGA standalone, but not from within QGIS - nothing appears in the Processing Toolbox. I tried following Why is SAGA from the Processing Plugin ...
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1answer
583 views

Using Raster calculator SAGA PyQGIS

I'm trying to plus two raster images through the python interface of QGIS, i want to use the saga raster calculator, but i got one error but i don't know why: i'm doing the following calculation (the ...
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1answer
762 views

SAGA tools not working in QGIS 2.18

I've only just started using QGIS (done some things in ArcGIS before) and SAGA tools don't work. The results don't make sense, QGIS stops answering or there is a python error. Could it be that there ...
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2answers
1k views

SAGA GIS, how to generate groundwater contour lines from points?

I'm trying to generate contour lines/isolines from groundwater points (groundwater depth) with SAGA (I tried before with QGIS, contour plugin, but the result was not good looking, too angular lines). ...
3
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2answers
1k 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 ...
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1answer
164 views

Slope Aspect Curvature algorithm giving error

I am trying to execute the slope aspect curvature algorithm in QGIS using a stand-alone script. When I run this code, I am getting a 'problem executing algorithm' error, which occurs when trying to ...
4
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1answer
692 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 ...
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1answer
1k views

Add raster value to features AttributeError: 'module' object has no attribute 'TYPE_RASTER'?

When I try to run the "add raster value to features" (available into SAGA Tools), I get this error: Traceback (most recent call last): File "/usr/share/qgis/python/plugins/processing/gui/...
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2answers
1k views

Error in raster Analysis in QGIS

I'm trying to conduct raster analysis in QGIS on a digital elevation model with a grid resolution of 5 cm. The disk size for the data set is 151 MB. When using default GDAL raster calculator it throws ...
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1answer
697 views

Method of multiple values - Rasterize SAGA

I'm converting a thematic shapefile (polygons) into a raster file using the Rasterize-SAGA algorithm. What criteria should I use to decide for [0] last, [1] first, [2] minimum, [3] maximum, [4] mean ...
9
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1answer
623 views

Which SAGA versions does QGIS 2.18.10 support?

Beginning with QGIS 2.18.10 the SagaAlgorithmProvider do not longer have a dictionary called supportedVersions. Previously, it looked like this: supportedVersions = {"2.1.2": ("2.1.2", ...
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2answers
2k views

Get values of terrain elevation of roads in QGIS?

I have one DEM raster layer with elevation values and one vector layer of the roads; same size, extension and CRS. I want to do what this guy did here: http://youarealegend.blogspot.de/2012/07/...
3
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1answer
636 views

How to add a WMS in SAGA GIS

This question seems simple but I couldn't get it done for most of the layers I tested: This is the adress that is predefined. It works with a small subset ogc.bgs.ac.uk/cgi-bin/...
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0answers
105 views

Copying coordinate system and extent from a TIFF to a polygon shapefile in SAGA GIS

I used R to batch process object based image segmentation on some geoTIFF files using rgdal to communicate with SAGA GIS. I got the resulting shapefiles, all with the following properties: Projection ...
2
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1answer
478 views

How to make ordinary krigging with a spherical variogram in SAGA GIS?

I have a very special map to make: it's a sea bird density map. To do this, I interpolate the observation points with ordinary kriging with a variogram. As I've read, the variogram must be of "...
3
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1answer
2k views

SAGA grid tools not found on QGis 2.14.15

I am missing all grid tools from SAGA in QGis 2.14.15. I know it's a question that has been asked before (there : SAGA grid tools missing in QGIS ) but unfortuately the answer given in this post did ...
2
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1answer
277 views

Using SAGA reclassification with tabled categories in QGIS script

I am using QGIS, and I would like to write a script to help processing the data. To do so, I have to reclassify heights values from a raster. I have written the following code, where retab is the ...
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0answers
248 views

“Unknown option 'CAREA'” in SAGA Catchment area algorithm for QGIS

18.7 version ans I try to use SAGA algorithm Catchment area and I take Unexpected error because that algorithm look easy. I test with the different raster layer and the some error. Maybe I have ...
1
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1answer
282 views

How to extract planting lines from a raster image?

I have a high quality drone image and I want to remove the soil and leave only the planting line.So far already able to classify the images leaving 1 for the plantations and 0 for the soil, it is a ...
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0answers
190 views

Calling SAGA modules through GRASS run_command in a script PYTHON

Does someone have an experience|example of calling modules of SAGA with the grass.run_command method in a script written in PYTHON?
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0answers
124 views

Saga GIS at command line in OSGeo4W - 'shapes to grid' tool - sqlite input

I have been using the Saga 'Rasterize' plugin in QGIS to rasterize spatial data from sqlite format (road networks, and intersections) to tiff. I find this tool more flexible than the gdal_rasterize ...
4
votes
1answer
894 views

Replacing 0 values of a raster with values from another raster in QGIS?

What I want to do is pretty straight forward: I have two raster with the same crs, resolution and extent. Both rasters show the number of days an area is flooded so they just have two values. Raster a ...
1
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1answer
856 views

Methods in Slope, Aspect SAGA calculations

Using this algorithm in QGIS I can choose between 7 methods, the default one being by Zevenbergen & Thorne 1987. What's the difference between them and can I just use the default one without ...
0
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1answer
182 views

Making DEM raster file using centroid point shapefile in QGIS? [closed]

I had a DEM file at first. Then I converted it to centroid points vector to add some data to it. So, I ended up with a vector with millions of points. Now I added my data and I want to use "elevation" ...
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0answers
305 views

Analytical Hierarchy Process (AHP) tool: Input layers do not have same grid extent [duplicate]

I am using this tool to create a suitability map for landfill site selection. However, when I gave the input raster layers, the .csv file for comparison table and run the tool, an error message saying-...
4
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2answers
403 views

Determining best neighbourhood search radius for Topographic Position Index (TPI) for predictive soil mapping?

I'm not sure how to determine the best input values for a search radius to create a TPI for the purpose of predictive soil mapping. Would this depend on the spatial extent of the area I wish to map?...

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