### 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.

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.

##### fTools functions

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.

**表 6:** fTools Analysis tools
**Analysis tools available via the fTools plugin** |

**Icon** | **Tool** | **Purpose** |

| 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. |

| Sum line length | Calculate
the total sum of line lengths for each polygon of a polygon vector layer. |

| Points in polygon | Count
the number of points that occur in each polygon of an input polygon vector
layer. |

| List unique values | List
all unique values in an input vector layer field. |

| Basic statistic | Compute
basic statistics (mean, std dev, N, sum, CV) on an input field. |

| Nearest Neighbor analysis
| Compute nearest neighbour statistics to assess the level of clustering in a
point vector layer. |

| 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. |

| 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. |

**表 9:** fTools Geometry tools
**Geometry tools available via the fTools plugin** |

**Icon** | **Tool** | **Purpose** |

| Check geometry |
Check polygons for intersections, closed-holes, and fix node ordering. |

| Export/Add geometry
columns | Add vector layer geometry info to point (XCOORD, YCOORD),
line (LENGTH), or polygon (AREA, PERIMETER) layer. |

| Polygon centroids |
Calculate the true centroids for each polygon in an input polygon layer. |

| Delaunay triangulation |
Calculate and output (as polygons) the delaunay triangulation of an input point vector layer. |

| Simplify geometry |
Generalise lines or polygons with a modified Douglas-Peucker algorithm. |

| Multipart to
singleparts | Convert multipart features to multiple singlepart features.
Creates simple polygons and lines. |

| Singleparts to
multipart | Merge multiple features to a single multipart feature based
on a unique ID field. |

| Polygons to lines
| Convert polygons to lines, multipart polygons to multiple singlepart lines. |

| Extract nodes |
Extract nodes from line and polygon layers and output them as points. |