Using grass gis7/13/2023 ![]() The existing graphical user interface has been significantly improved and extended with new functionality not easily found in other GIS. Histogram support in legends added and much more. further binary packages for other Linux distributions will follow shortly.ĭisplay system and graphical user interface: New portable display system, used in the graphical user interface but as usual also with command line support. To get the GRASS GIS 7.0.0 source code directly from SVN, see here. GRASS GIS 7.0.0 also offers significantly improved performance for many raster and vector modules: "Many processes that would take hours now take less than a minute, even on my small laptop!" explains Markus Neteler, the coordinator of the development team composed of academics and GIS professionals from around the world. As a stable release 7.0 will enjoy long-term support. GRASS GIS 7.0.0 ships 10,500 fixes and improvements with respect to GRASS GIS 6.4.0 after more than six years of development. Finally, there are a series of new modules to analyse raster and vector data some of the already existing modules were improved and made faster (some even 1000 x faster). A lot of effort has been invested to standardize parameter and flag names. This required a easy to manage topology format update including a new spatial index. Furthermore, the vector library was significantly improved to make it faster and more efficient, along with support of huge files. The developers added important new functionality to the core system, among that the new Python interface to the C library. This new API permits users to create new GRASS GIS-Python modules in a simple way while yet obtaining powerful and fast modules. The old Tcl/Tk based GUI has been dropped. The graphical user interface based on wxPython has been enriched with many new features in order to make complex GIS operations available as simple as possible. That’s all, and remember, the GRASS manual pages are generally pretty clear and often give some good examples.After many years of development the new stable major release GRASS GIS 7.0.0 is available. V.to.db layer=1 qlayer=1 option=area units=hectares columns=Area Of course, you can use the command line, which is only two lines if you include the command to create the column: v.db.addcolumn layer=1 columns='Area DOUBLE PRECISION' The last thing to fill in is the name of the attribute column(s). Furthermore you can indicate in which units you want these values (e.g., surface areas can be in acres, hectares or square meters, kilometers, feet, or miles). ![]() In the ‘Optional’ tab (Figure 3), you can mark for which feature types you want to calculate the values. The ‘Print’ tab is there is you want to print the results to the console instead of uploading the values to the attribute table. You can skip the ‘Query’ tab, that is if you want to update the values of a column based on other columns in the attribute table. You normally should not be concerned with the ‘Layer numbers’ and ‘Query layer number’ options, but check the manual if you want to know more about these option. Check the manual to see what these different values are. There are various values that can be uploaded. ![]() In the first tab on the screen (Figure 1), fill in the vector layer and the value to be uploaded. Having done that we can go back to v.to.db. Or, type on the command line v.db.addcolumn layer=1 columns='Area DOUBLE PRECISION' The data type should be double precision. For example, create a column ‘Area’ to hold the surface area of the polygons. Give the name of the vector layer and the name of the new column and data type. Type v.db.addcolumn on the command line or use the menu Database | vector database connection | add column. It means you first need to create a column in the attribute table which will hold your geometry value. But before we go into these options, it is important to realize that v.to.db can write values to existing columns only. You can type this in the console or through the menu ( menu | vector | update attribute), which both will give you the following screen: Figure 1Īs you can see, you are presented with quite a few option. Below I will briefly explain how to use this tool using the GUI or command line. It is slightly more complicated (don’t worry, it is still easy enough), but also more powerful. In my previous post I explained how to add geometry values to the attribute table of a vector map in QGIS.
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