# ipdw v0.2-9

Monthly downloads

## Spatial Interpolation by Inverse Path Distance Weighting

Functions are provided to interpolate geo-referenced point data via
Inverse Path Distance Weighting. Useful for coastal marine applications where
barriers in the landscape preclude interpolation with Euclidean distances.

## Readme

# ipdw

The `R`

package
ipdw provides the
functionality to perform interpolation of georeferenced point data using
inverse path distance weighting. Interpolation is accomplished in two
steps. First, path distances are calculated from each georeferenced
(measurement) point to each prediction point. Path distances, which
honor barriers in the landscape, are calculated based on cell-to-cell
movement through an underlying `Raster`

object that represents movement
cost. These path distances are subsequently used as interpolation
weights. The two-step routine follows the order of operations described
in Suominen et al. (2010) substituting the ESRI path distance algorithm
with the `gdistance`

wrapped version of the `igraph`

adjacency
algorithm.

The ipdw package was developed with coastal marine applications in mind where path distances (as the fish swims) rather than Euclidean (as the crow flies) distances more accurately represent spatial connectivity. Interpolation of sparse grids in coastal areas otherwise end up bleeding through land areas.

## Installation

### Stable version from CRAN

```
install.packages("ipdw")
```

### or development version from GitHub

```
install.packages('devtools') # package devtools needed
devtools::install_github("jsta/ipdw")
```

## Examples

**see** vignette

## References

**Joseph Stachelek and Christopher J. Madden (2015)**. Application of
Inverse Path Distance weighting for high density spatial mapping of
coastal water quality patterns. *International Journal of Geographical
Information Science*
preprint |
journal

**Tapio Suominen, Harri Tolvanen, and Risto Kalliola (2010)**. Surface
layer salinity gradients and flow patterns in the archipelago coast of
SW Finland, northern Baltic Sea. *Marine Environmental Research*
journal

## Functions in ipdw

Name | Description | |

ipdwInterp | Inverse Distance Weighting with custom distances | |

ipdw | Inverse Path Distance Weighting | |

errorGen | Generate interpolation error stats from validation datasets | |

costrasterGen | Generate a cost Raster | |

pathdistGen | Generate a stack of path distance raster objects | |

rm_na_pointslayers | Remove NA SpatialPointsDataFrame features and drop corresponding raster stack layers | |

No Results! |

## Vignettes of ipdw

Name | ||

images/plot_ipdw_vs_idw-1.png | ||

images/plot_validation-1.png | ||

ipdw2.Rmd | ||

ipdw2.bib | ||

No Results! |

## Last month downloads

## Details

URL | https://www.github.com/jsta/ipdw |

BugReports | https://www.github.com/jsta/ipdw/issues |

License | GPL (>= 2) |

Encoding | UTF-8 |

LazyData | true |

RoxygenNote | 7.1.0 |

VignetteBuilder | knitr |

NeedsCompilation | no |

Packaged | 2020-07-20 15:09:26 UTC; julie |

Repository | CRAN |

Date/Publication | 2020-07-22 13:50:02 UTC |

#### Include our badge in your README

```
[![Rdoc](http://www.rdocumentation.org/badges/version/ipdw)](http://www.rdocumentation.org/packages/ipdw)
```