Plugins ftools
fTools Plugin
The goal of the fTools python plugin is to provide a one-stop resource for
many common vector-based GIS tasks, without the need for additional software,
libraries, or complex workarounds. It provides a growing suite of spatial
data management and analysis functions that are both fast and functional.
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fTools is now automatically installed and enabled in new versions of QGIS, and as with all plugins, it can
be disabled and enabled using the Plugin Manager (See Section #sec:managing_plugins).
When enabled, the fTools plugin adds a Tools menu to QGIS, providing functions ranging from
Analysis and Research Tools to Geometry and Geoprocessing Tools, as well as several useful Data Management Tools.
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fTools functions<A NAME="ftool_functions"></A>
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Tables 6 through 10 list the functions available via the fTools plugin, along with a brief description of each function. For further information on an individual fTools function, please click the fTools Information menu item in the Tools menu.
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Analysis tools available via the fTools plugin | ||
Icon | Tool | Purpose |
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[width=0.7cm]matrix | Distance Matrix | Measure distances between two point layers, and output results as a) Square
distance matrix, b) Linear distance matrix, or c) Summary of distances. Can limit distances to the k nearest features. |
[width=0.7cm]sum_lines | Sum line length | Calculate the total sum of line lengths for each polygon of a polygon vector layer. |
[width=0.7cm]sum_points | Points in polygon | Count
the number of points that occur in each polygon of an input polygon vector layer. |
[width=0.7cm]unique | List unique values | List all unique values in an input vector layer field. |
[width=0.7cm]basic_statistics | Basic statistic | Compute basic statistics (mean, std dev, N, sum, CV) on an input field. |
[width=0.7cm]neighbour | Nearest Neighbor analysis | Compute nearest neighbour statistics to assess the level of clustering in a point vector layer. |
[width=0.7cm]mean | Mean coordinate(s) | Compute either the normal or weighted mean center of an entire vector layer, or multiple features based on a unique ID field. |
[width=0.7cm]intersections | Line intersections | Locate intersections between lines, and output results as a point shapefile.
Useful for locating road or stream intersections, ignores line intersections with length > 0. |
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Research tools available via the fTools plugin | ||
Icon | Tool | Purpose |
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[width=0.7cm]random_selection | Random selection | Randomly select n number of features, or n percentage of features |
[width=0.7cm]sub_selection | Random selection within subsets | Randomly select features within subsets based on a unique ID field. |
[width=0.7cm]random_points | Random points | Generate pseudo-random points over a given input layer. |
[width=0.7cm]regular_points | Regular points | Generate a regular grid of points over a specified region and export them as a point shapefile. |
[width=0.7cm]vector_grid | Vector grid | Generate a line or polygon grid based on user specified grid spacing. |
[width=0.7cm]select_location | Select by location | Select features based on their location relative to another layer to form a new selection, or add or subtract from the current selection. |
[width=0.7cm]layer_extent | Polygon from layer extent | Create a single rectangular polygon layer from the extent of an input raster or vector layer. |
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Geoprocessing tools available via the fTools plugin | ||
Icon | Tool | Purpose |
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[width=0.7cm]convex_hull | Convex hull(s) | Create minimum convex hull(s) for an input layer, or based on an ID field. |
[width=0.7cm]buffer | Buffer(s) | Create buffer(s) around features based on distance, or distance field. |
[width=0.7cm]intersect | Intersect | Overlay layers such that output contains areas where both layers intersect. |
[width=0.7cm]union | Union | Overlay layers such that output contains intersecting and non-intersecting areas. |
[width=0.7cm]sym_difference | Symetrical difference | Overlay layers such that output contains those areas of the input and difference layers that do not intersect. |
[width=0.7cm]clip | Clip | Overlay layers such that output contains areas that intersect the clip layer. |
[width=0.7cm]difference | Difference | Overlay layers such that output contains areas not intersecting the clip layer. |
[width=0.7cm]dissolve | Dissolve | Merge features
based on input field. All features with indentical input values are combined to form one single feature. |
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Geometry tools available via the fTools plugin | ||
Icon | Tool | Purpose |
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[width=0.7cm]check_geometry | Check geometry | Check polygons for intersections, closed-holes, and fix node ordering. |
[width=0.7cm]export_geometry | Export/Add geometry columns | Add vector layer geometry info to point (XCOORD, YCOORD), line (LENGTH), or polygon (AREA, PERIMETER) layer. |
[width=0.7cm]centroids | Polygon centroids | Calculate the true centroids for each polygon in an input polygon layer. |
[width=0.7cm]delaunay | Delaunay triangulation | Calculate and output (as polygons) the delaunay triangulation of an input point vector layer. |
[width=0.7cm]simplify | Simplify geometry | Generalise lines or polygons with a modified Douglas-Peucker algorithm. |
[width=0.7cm]multi_to_single | Multipart to singleparts | Convert multipart features to multiple singlepart features. Creates simple polygons and lines. |
[width=0.7cm]single_to_multi | Singleparts to multipart | Merge multiple features to a single multipart feature based on a unique ID field. |
[width=0.7cm]to_lines | Polygons to lines | Convert polygons to lines, multipart polygons to multiple singlepart lines. |
[width=0.7cm]extract_nodes | Extract nodes | Extract nodes from line and polygon layers and output them as points. |
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Data management tools available via the fTools plugin | ||
Icon | Tool | Purpose |
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[width=0.7cm]export_projection | Export to projection | Project features to new CRS and export as new shapefile. |
[width=0.7cm]define_projection | Define projection | Specify the CRS for shapefiles whose CRS has not been defined. |
[width=0.7cm]join_attributes | Join attributes | Join
additional attributes to vector layer attribute table and output results to a new shapefile. Additional attributes can be from a vector layer or stand-alone dbf table. |
[width=0.7cm]join_location | Join attributes by location | Join additional attributes to vector layer based on spatial
relationship. Attributes from one vector layer are appended to the attribute table of another layer and exported as a shapefile |
[width=0.7cm]split_layer | Split vector layer | Split input layer into multiple separate layers based on input field. |
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