Fix article images

Author: pvanlaake

vignettes/articles/32_R-CF.Rmd

@@ -27,7 +27,7 @@ This article presents a view of CF from the perspective of R. The main elements
 
 By definition, a CF-compliant data set is stored in a netCDF file. The CF elements and their relationship to the building blocks of the netCDF file are given in the figure below:
 
-![*Figure 1: Elements of a netCDF file and the CF constructs built on them. Source: CF Conventions, Appendix I.*](../datamodel-0.4.svg){width="680"}
+![*Figure 1: Elements of a netCDF file and the CF constructs built on them. Source: CF Conventions, Appendix I.*](datamodel-0.4.svg){width="680"}
 
 If you've worked with netCDF data in R before, probably using package `ncdf4` (but what follows is equally true when you use package `RNetCDF`), you should be familiar with the yellow boxes in the above figure, especially "NC::Variable" (the specific notation used in the figure is not important here), corresponding to the `ncvar4` class in
 `ncdf4`. CF, however, recognizes 11 different objects that are each based on an "NC::Variable". This ranges from axes, or *generic coordinate variables* in the white box in the figure, to *grid mapping variables* (that define the coordinate reference system of your data) to the actual data array in a *data variable*. This is the source of all those surprising "variables" that you see when you do `names(nc$var)`:
@@ -132,11 +132,11 @@ Note how in the `array()` version the `x` and `y` axes are reversed and the `y`
 
 The netCDF file format is very flexible, as well as CF, and the `ncdfCF` package uses a layered structure to capture it all. This structure enables a full support of the features provided by the `netcdf` library and the CF Conventions.
 
-![Figure 2: Core ncdfCF data model](../ncdfCF-datamodel-0.7.png){width="680"}
+![Figure 2: Core ncdfCF data model](ncdfCF-datamodel-0.7.png){width="680"}
 
 Each of the building blocks may have other objects associated with it, such as axes for `CFVariable`. Package `ncdfCF` is built using the `R6` OOP framework and uses class hierarchies throughout. The crucial but humble "virtual" class `CFAxis` is not used directly, instead you'll work with its seven descendant classes. `CFVariable` has several specialised sub-classes, such as `CFVariableL3b` for NASA level-3 binned data used for MODIS imagery, or `CFVerticalParametricTerm` which you will encounter when using *formula terms* for a parametric vertical axis.
 
-![Figure 3: Condensed ncdfCF axis class hierarchy](../ncdfCF-hierarchy-0.7.png){width="680"}
+![Figure 3: Condensed ncdfCF axis class hierarchy](ncdfCF-hierarchy-0.7.png){width="680"}
 
 ## Feature matrix