add readme.md

Author: joheisig

README.Rmd

@@ -10,7 +10,7 @@ The goal of GEDIcalibratoR is to facilitate location calibration for GEDI. It ma
 
 You can install the development version of GEDIcalibratoR from [GitHub](https://github.com/) with:
 
-```{r}
+```{r, eval=FALSE}
 devtools::install_github("joheisig/GEDIcalibratoR")
 ```
 
@@ -26,8 +26,10 @@ The package is currently usable. GEDI data can be calibrated using digital surfa
 
 ```{r}
 library(GEDIcalibratoR)
+library(sf)
 grid_ext = system.file("demodata/grid_ext.rds", package = "GEDIcalibratoR") |> readRDS()
 shifts = shift_stats(grid_ext)
+head(shifts)
 plot_shift_stats(shifts)
 
 bs = get_best_shift(grid_ext, shifts)

README.md

@@ -0,0 +1,74 @@
+
+# GEDIcalibratoR
+
+The goal of GEDIcalibratoR is to facilitate location calibration for
+GEDI. It makes downloading tiles of ALS, DEM, and DEM data easy and
+evaluates possible spatial shifts using user-defined calibration grids.
+The best suitable shift can then be applied to the original data and may
+improve statistical models and following analyses. GEDIcalibratoR also
+provides functions to visualize calibration effects.
+
+## Installation
+
+You can install the development version of GEDIcalibratoR from
+[GitHub](https://github.com/) with:
+
+``` r
+devtools::install_github("joheisig/GEDIcalibratoR")
+```
+
+## Development Goals
+
+The package is currently usable. GEDI data can be calibrated using
+digital surface and elevation models. More functionality shall be added
+in the future, e.g.:
+
+-   support of more complex calibration variables derived from ALS point
+    clouds
+-   more criteria to select the best shift (besides RMSE)
+-   more and more flexible plotting options
+
+## Example
+
+``` r
+library(GEDIcalibratoR)
+library(sf)
+```
+
+    ## Linking to GEOS 3.10.2, GDAL 3.4.1, PROJ 8.2.1; sf_use_s2() is TRUE
+
+``` r
+grid_ext = system.file("demodata/grid_ext.rds", package = "GEDIcalibratoR") |> readRDS()
+shifts = shift_stats(grid_ext)
+head(shifts)
+```
+
+    ## Simple feature collection with 6 features and 8 fields
+    ## Geometry type: MULTIPOINT
+    ## Dimension:     XY
+    ## Bounding box:  xmin: 245937.5 ymin: 5678698 xmax: 441963.1 ymax: 5701985
+    ## Projected CRS: ETRS89 / UTM zone 33N
+    ## # A tibble: 6 × 9
+    ##   file                            step angle     n mean_diff sd_diff  rmse    r2
+    ##   <chr>                          <dbl> <dbl> <int>     <dbl>   <dbl> <dbl> <dbl>
+    ## 1 GEDI02_A_2019249020326_O04149…     0     0   114      2.18    3.08  3.12 0.775
+    ## 2 GEDI02_A_2019249020326_O04149…     3     0   115      2.16    2.95  3.03 0.793
+    ## 3 GEDI02_A_2019249020326_O04149…     3    30   114      2.18    2.95  3.03 0.793
+    ## 4 GEDI02_A_2019249020326_O04149…     3    60   114      2.10    2.89  2.95 0.800
+    ## 5 GEDI02_A_2019249020326_O04149…     3    90   113      2.09    2.88  2.93 0.803
+    ## 6 GEDI02_A_2019249020326_O04149…     3   120   114      2.10    2.90  2.95 0.799
+    ## # … with 1 more variable: geometry <MULTIPOINT [m]>
+
+``` r
+plot_shift_stats(shifts)
+```
+
+![](README_files/figure-gfm/unnamed-chunk-2-1.png)<!-- -->
+
+``` r
+bs = get_best_shift(grid_ext, shifts)
+ns = get_no_shift(grid_ext, shifts)
+plot_calibration(bs, ns, label = c("Best","Ref"), color = c("forestgreen", "firebrick"))
+```
+
+![](README_files/figure-gfm/unnamed-chunk-2-2.png)<!-- -->