Gis

Spatial correlation between rasters

In this blog article, I propose a way to look at the spatial repartition of correlation between two rasters. For your own reason, you may want to know the correlation between rasters, but a unique value issued from fonction cor is not enough. You would like to know if there are variations of …

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Spatial interpolation on Earth as a 3D sphere

Earth map is usually presented flat. Geographical coordinates usually go from -180° to +180°. Spatial interpolations using coordinates may be tricky as -180° is equal to +180°. Here I propose a way to realize spatial interpolations on Earth as a sphere and then map the outputs in 3D using rgl. The …

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Polygons tint band with leaflet and simple feature (library sf)

Stackoverflow is again a source of inspiration. I found this question on tint bands in leaflet, not related to R originally but I though I could answer it with R easily. This is also a good one for me to play with this new simple feature library sf and use it with leaflet. My simple solution is to …

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How to fill a hatched area polygon with holes in leaflet with R

Drawing polygons filled with a hatched background is quite easy with classical plot in R. This only requires to define density and angle parameters of polygon function. SpatialPolygons from library sp also uses this polygon function. However, if you want to draw a hatched area of a SpatialPolygons …

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Plot a specific image in a delimited polygon as repeated pattern on a map

A question on stackoverflow asked how to draw trees in a polygon to represent a forest area on a map. I first thought about plotting “emoji” on a regular point pattern sampled in the polygon. Library sp allows for sampling points in a delimited SpatialPolygons which was exactly what I was looking …

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Add multiple layers in leaflet widget with R

Library leaflet with R is well integrated with pipe writing (%>%). Thus, it is really easy to add multiple layers and options in a leaflet widget. If you want to add a lot of layers in your widget, it is not necessary to provide a “addPolygons” for each of these layers, you can simply use a loop. …

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Mapping, spatial analyses and GIS with R

If you download the following presentation, you will find a presentation of different functions in the R-software useful for spatial data manipulations. Choosing the right libraries allows to create, import, modify, manipulate and map vector (shapefiles) or matrix (raster) spatial data. Your spatial …

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