Can a grass tool be run from QGIS?

Can a grass tool be run from QGIS?

GRASS modules can be run from QGIS GRASS Tools if QGIS was started from a GRASS shell or if a GRASS mapset was opened from QGIS. The modules work with GRASS data only. It is easy to modify the menu and add new modules because both the menu and the modules are defined in XML configuration files.

What is the Processing Toolbox in QGIS?

The Processing Toolboxis the main element of the processing GUI, and the one that you are more likely to use in your daily work. It shows the list of all available algorithmsgrouped in different blocks called Providers, and custom modelsand scriptsyou can add to extend the set of tools.

Where are QGM files stored in QGIS-GRASS?

The QGM definition is written in XML format file with extension .qgm, one for each QGIS-GRASS module. Configuration files are stored in _*qgis/src/plugins/grass/modules*_ directory and installed in _*share/qgis/grass/modules*_ directory. The name of the file should start with GRASS module name + a word describing the specific task.

What are the rules for using grass tools?

GRASS Tools are intended mostly for beginners and not very experienced users. The basic rules are: Each module should have 3 or less options; if it seems to be necessary to add more options, it should be discussed beforehand Module definition should be robust so that it doesn’t allow a user to run a module with wrong option.

Which is the latest version of QGIS for Linux?

Latest stable and LTR packages called qgis and qgis-ltr are available in the following repositories: All packages include GRASS and Python support. Arch Linux is available in official repository : https://www.archlinux.org/packages/community/x86_64/qgis/ QGIS Long Term Release is available in AUR (Arch User Repository).

Is there a way to install QGIS from the Internet?

QGIS and all dependencies are included, along with Python, GRASS, GDAL, etc. The install er is able to install from internet or just download all needed packages beforehand. The downloaded files are kept in a local directory for future installations. Steps are: Before install ing any of the nightly builds note the warning.

Why is my GRASS plugin not loading osgeo4w?

When I opened OSGeo4W installer and looked under Lib, the plugin for 3.10 was skipped. I recently started installing both 3.10 and 3.4, so maybe there’s an issue when you install both it only installs the plugin for one of them by default. so maybe there’s an issue when you install both it only installs the plugin for one of them by default.

How to select a feature in grass tool?

Features (and their categories, GRASS feature ID equivalent) can be selected either with ‘Select Features’ tool or in the attribute table. The list of categories is updated dynamically. Example (v.extract.list.qgm): key — name of module option in GMO. answer — default value (overwrites GMO default value); value “on” will switch on a flag.

Is the mapcalc tool similar to QGIS raster calculator?

The Mapcalc tools is similar to the Raster Calculator of QGIS. You can perform mathematical operation on one or more raster layers and the final result will be a new layer with the calculated values. The aim of the next exercise is to extract the values greater than 1000 from the g_dem raster layer.

What are the parts of the GRASS GIS integration?

The integration consists of two parts: provider and plugin. The provider allows to browse, manage and visualize GRASS raster and vector layers. The plugin can be used to create new GRASS locations and mapsets, change GRASS region, create and edit vector layers and analyze GRASS 2-D and 3-D data with more than 400 GRASS modules.

What can you do with GRASS GIS plugin?

The GRASS plugin provides access to GRASS GIS databases and functionalities (see GRASS-PROJECT in Literature and Web References ). This includes visualizing GRASS raster and vector layers, digitizing vector layers, editing vector attributes, creating new vector layers and analysing GRASS 2-D and 3-D data with more than 400 GRASS modules.

How to clean topology error in QGIS geodose?

The best way to clean topology error is by manual editing, but it’s tiring and time consuming. Fortunately, there are some tools that can be used to clean topology error in QGIS such as geometry checker and Grass v.clean tool. But must be kept in mind, using the tools not always working perfectly for any cases,…

Why are there no attribute table in QGIS?

WARNING: Unable to determine input map’s vector feature type (s). WARNING: No attribute table found -> using only category numbers as attributes To check the validity of my layers, I opened a blank map with the correct CRS and ran the Shortest Path tool from different points all over the map.

Why are the layers not correctly generated in QGIS?

The following layers were not correctly generated. You can check the ‘Log Messages Panel’ in QGIS main window to find more information about the execution of the algorithm. File “C:\\OSGEO4~1\\apps\\grass\\grass78\\etc\\grass78.py”, line 2216, in

Why is my grass tool returning an error?

Every single GRASS tool returns an error (will talk more specifically about what this is later). I searched stack exchange high and low, with no luck. My first hunch was that there was something funky with the CRS. However, after setting the data frame’s CRS to the layers, nothing changed.

Can a SVG picture be generated from QGIS?

SVG and PNG pictures can be generated from QGIS using Map Composer. The size of PNG images should be larger than the expected icon size, because it is expected to be later used in automatically generated documentation, where pictures will be used in larger size.

Is there a raster calculator available in QGIS?

In the QGIS raster menu only raster calculator is available, how do you get other tools, like wrap (reproject)? Please see the image below. Problem: Processing plugin has been disabled.

Are there any processing tools in QGIS 2.16?

I’ve installed Qgis 2.16, the first time without tools because there were problems with PyQGIS libraries after uninstalled old versions. Then i decided to fully uninstall Qgis, deleted “.qgis2” folder in my Userprofile folder, deleted some keys related with Qgis in Regedit (Windows OS), cleaned OS and finally reinstalled Qgis without problems.

How to uncheck a layer in QGIS documentation?

Ctrl -click on a checked / unchecked layer will uncheck / check the layer and all its parents. Enabling the Mutually Exclusive Group option means you can make a group have only one layer visible at the same time.

Is there no attribute table for grass tools?

WARNING: No attribute table found -> using only category numbers as attributes To check the validity of my layers, I opened a blank map with the correct CRS and ran the Shortest Path tool from different points all over the map. It worked just fine.

Where to find vector import tool in QGIS?

As soon as it’s loaded, click on the GRASS Tools button: In the new dialog, select Modules list. Find the vector import tool by entering the term v.in.ogr.qgis in the Filter field.

Where to find Dem in QGIS exercise data?

Recall that our DEM is in the Projected CRS UTM 33S / WGS 84, but our GRASS project is in the Geographic CRS WGS 84. So let’s re-project the DEM first. Load the srtm_41_19.tif dataset (found under exercise_data/raster/SRTM/) into the QGIS map as usual, using QGIS’ Add Raster Layer tool.

Why is the processing menu missing in QGIS?

So please check if you have deactivated the Processing plugin in the Plugin Manager. Processing sometimes crashes or takes a long time to load. so sometimes QGIS disables it. As @underdark answered, re-enable it from plugins menu. Thanks for contributing an answer to Geographic Information Systems Stack Exchange!

How is image processing done in GRASS GIS?

For a general overview, see “Introduction: image processing in GRASS GIS” at imageryintro . Digital numbers and physical values (reflection/radiance-at-sensor):

When was the first version of QGIS released?

It was first released in 1984, and has seen much improvement and additional functionality since then. QGIS allows you to make use of GRASS’ powerful GIS tools directly. 12.1. Lesson: GRASS Setup

Where can I download the QGIS installer for Python?

QGIS and all dependencies are included, along with Python, GRASS, GDAL, etc. The installer is able to install from internet or just download all needed packages beforehand. The downloaded files are kept in a local directory for future installations. Steps are: Before installing any of the nightly builds note the warning.

Where can I find the QGIS Processing Toolbox?

It is a plugin that you might have to enable with the menu Plugins > Manage and Install Plugins menu. Not the answer you’re looking for? Browse other questions tagged qgis or ask your own question.

What’s the latest version of the GRASS plugin?

Grass 7.0.5 is a recent release, like less than a week. QGIS and the GRASS 7 plugin haven’t been updated to catch up – e.g. if you look at the batch file launchers in \\bin you’ll see they all refer to 7.0.4. What you need to do is launch the OSGeo4W setup, go to Advanced Install, navigate to the package list, and roll it back to 7.0.4.

How to add raster layer to QGIS map?

Load the srtm_41_19.tif dataset (found under exercise_data/raster/SRTM/) into the QGIS map as usual, using QGIS’ Add Raster Layer tool. Re-project it using GDAL Warp tool ( Raster ‣ Projections ‣ Warp (Reproject) ), setting it up as shown:

The GRASS plugin provides access to GRASS GIS (see GRASS-PROJECT Literature and Web References) databases and functionalities. This includes visualization of GRASS raster and vector layers, digitizing vector layers, editing vector attributes, creating new vector layers and analysing GRASS 2D and 3D data with more than 400 GRASS modules.

How to add a vector layer to a GRASS GIS?

Click on Add GRASS raster layer, choose the map name gtopo30 and click [OK]. The elevation layer will be visualized. Click on Add GRASS vector layer, choose the map name alaska and click [OK]. The Alaska boundary vector layer will be overlayed on top of the gtopo30 map.

Where to find GRASS GIS in layer manager?

On Linux and Windows platforms, the layer manager also has a menu bar with a set of pull-down menus for all GRASS GIS functions (analysis, file I/O, GIS configuration and management); on a Mac, the GRASS functions menu is at the top of the screen. The top left button of the toolbar opens a new Map Display Window.

Where to find processing tools in vector menu of QGIS?

Since some time, it has become a core plugin, so no need to be in the users .qgis2/python/plugins/processing folder. You can remove that savely. Apart from that, I discovered a second Vector menue right to the Help menu, if my locale is not US English.

How to create Slope area grid in QGIS?

Creates a grid of slope-area values = (Sm) (An) based on slope and specific catchment area grid inputs, and parameters m and n. This tool is intended for use as part of the slope-area stream raster delineation method. This input is a grid of slope values. This grid can be obtained from the “D-Infinity Flow Directions” tool.

Why is QGIS r.watershed raster map not found?

Looking at the log, it led to return an error The basin threshold must be a positive number and the job then terminated with the error Raster map or group not found. (Have not checked QGIS 3.0.2.) Thanks for contributing an answer to Geographic Information Systems Stack Exchange!

Is the basin threshold a positive number in QGIS?

(It sets threshold option to “0” in g.region command). Looking at the log, it led to return an error The basin threshold must be a positive number and the job then terminated with the error Raster map or group not found. (Have not checked QGIS 3.0.2.)

How to write new processing algorithms in QGIS?

Within QGIS, you can use Create new script in the Scripts menu at the top of the Processing Toolbox to open the Processing Script Editor where you can write your code. To simplify the task, you can start with a script template by using Create new script from template from the same menu.

What does the toolbox do in QGIS documentation?

It shows the list of all available algorithms grouped in different blocks called Providers, and custom models and scripts you can add to extend the set of tools. Hence the toolbox is the access point to run them, whether as a single process or as a batch process involving several executions of the same algorithm on different sets of inputs.

Can a QGIS provider be activated by default?

Providers can be (de)activated in the Processing settings dialog . By default, only providers that do not rely on third-party applications (that is, those that only require QGIS elements to be run) are active. Algorithms requiring external applications might need additional configuration.

Is it possible to import a QGIS module into pyqgis?

With PyQGIS, this is perfectly possible — import the qgis.core module, initialize it and you are ready for the processing. Or you may want to create an interactive application that uses some GIS functionality — measure some data, export a map in PDF or any other functionality.

Which is the best installer for QGIS Python?

For new users we recommend the standalone installers. For more advanced QGIS users you can use OSGeo4W packages, which make it possible to install several versions in parallel. The OSGeo4W repository contains a lot of software from OSGeo projects. QGIS and all dependencies are included, along with Python, GRASS, GDAL, etc.

Which is the latest version of GRASS GIS?

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here. v.to.rast – Converts (rasterize) a vector map into a raster map.

How to convert v.to.rast to grass?

When used with direct OGR access this is the layer name. type = string [,string,…] v.to.rast transforms GRASS vector map layers into GRASS raster map layer format. Optionally, attributes can be converted to raster category labels. In order to avoid unexpected results, the type of vector features should always be specified.

Where to find ” help ” in QGIS 3.12.0?

In qgis 3.12.0 under the drop down of “Help” – “Plugins” is listed with a small black arrow – clicking this does nothing. Sorry to have written a short essay! – but as I’ve spent days on trying to fix it thought it might be helpful.

How to get the processing Menu Back in QGIS?

The fTools plugin offered these menus and it has been removed from QGIS and is replaced with the processing plugin. Just enable the processing plugin and the menu will be back. Note that you can go to Processing => Options => Menus, to configure in detail which algorithms will be available in the menu.

How to enable your in processing in QGIS?

To enable R in Processing you need to install the Processing R Provider plugin and configure R for QGIS. Configuration is done in Provider ► R in the Processing tab of Settings ► Options. Depending on your operating system, you may have to use R folder to specify where your R binaries are located.

Can you execute an external algorithm in QGIS?

Once you have correctly configured the system, you will be able to execute external algorithms from any component like the toolbox or the graphical modeler, just like you do with any other algorithm. By default, algorithms that rely on an external application not shipped with QGIS are not enabled.

How to use v.build.check in QGIS?

The v.build.check algorithm simplifies the execution of some GRASS functions: You can read the manual of each function used by the algorithm: g.proj, v.in.ogr, g.region, v.build, and v.out.ogr.

When to use v.out.ogr in QGIS?

Precisely, these warnings are issued by the v.out.ogr function when no topology was created by v.build -e (that is, it didn’t find topological errors in the analyzed layer):

How to import raster and vector data into grass?

If you don’t see GRASS location item, verify in Help ‣ About ‣ Providers if GRASS vector provider is loaded. This section gives an example of how to import raster and vector data into a GRASS mapset.

How to create a new location in grass?

Create a new location with the co-ordinate system referred to by EPSG code 4326 (Latitude-Longitude/WGS84), without explicitly specifying datum transformation parameters: Create a new location with the co-ordinate system referred to by ESRI-EPSG code 900913 ( Google Mercator Projection)

How to repair topology of a shapefile in ArcGIS?

Some topological problems may be reported depending on the quality of your SHAPE file. These topological problems we can fix now in GRASS via toolbox using the topology tools: Vector -> Develop map -> Toolset for cleaning topology of vector map -> v.clean.break. Define a threshold in map units (for example 0.5 [m] or likewise).

Is there a skeletonize algorithm for grass 7.0?

GRASS 7.0 has v.skeleton which should be good enough but does not seem to be in for integration with QGIS in the near future. CGAL has skeletonize algorithms, of course, but the Python support is very poor. pySkeleton does not work for me and I probably don’t have time to salvage the code.

What should the target be in grass 7.0?

The target is a large thin polygon with holes representing street areas and I need to obtain an approximation of the road network via skeletonization. GRASS 7.0 has v.skeleton which should be good enough but does not seem to be in for integration with QGIS in the near future.

What does the V stand for in QGIS?

The v stands for “vector”, in means its a function to import data into the GRASS database, ogr is the software library used to read vector data, and qgis means that the tool will look for a vector from among the vectors already loaded into QGIS. Once you’ve found this tool, click on it to bring up the tool itself:

Is there a way to enable saga in QGIS?

Installed QGIS using OSGeo4W. Installed Dufour 2.1 under Program files. Apps directory shows saga_gui.exe (2.0.8). Grass plugin working ok. Install looks ok. The SAGA instructions mention a configuration dialogue without being a bit more accurate. https://www.qgis.org/en/docs/user_manual/processing/3rdParty.html.

How to import a vector layer in QGIS?

Scroll down to the modules tree item File -> Import vector -> v.in.ogr (for this example, we are using a vector layer here) Select the OGR file type (shapefile, MapInfo etc.), define a name for the output GRASS vector layer and select Run (note: do not select the check box for “Limit import to current region”)

Which is an example of the GRASS plugin?

With the GRASS plugin, you can load vector or raster layers using the appropriate button on the toolbar menu. As an example, we will use the QGIS Alaska dataset (see section Sample Data ). It includes a small sample GRASS LOCATION with three vector layers and one raster elevation map.

How to install grass addon in win 7?

Win 7 QGIS 2.0 GRASS 6.4.3 The solution is given in the r.viewshed.cva.py It is a Python script and the line 189 is: grass.run_command (“r.viewshed”,…. So you need to install r.vieshed first but most Windows computers don’t have a common compiler and a building environment built.

Where do I find the vector import tool in grass?

Find the vector import tool by entering the term v.in.ogr.qgis in the Filter field. The v stands for “vector”, in means its a function to import data into the GRASS database, ogr is the software library used to read vector data, and qgis means that the tool will look for a vector from among the vectors already loaded into QGIS.