add GetSDLValue function

.Rbuildignore

@@ -1,2 +1,3 @@
+^LICENSE\.md$
 ^.*\.Rproj$
 ^\.Rproj\.user$

DESCRIPTION

@@ -4,11 +4,11 @@ Version: 0.1.0
 Authors@R: person("Xiaodan", "Lyu", email = "[email protected]", role = c("aut", "cre"))
 Description: This package embed a shiny app to visualize soil survey data and cropland data layer. Some functions to fetch CDL file and values are also provided.
 Depends: R (>= 3.1.0)
-License: GPL-3
+License: MIT + file LICENSE
 Encoding: UTF-8
 LazyData: true
 Imports: raster, sp, XML, glue, dplyr, utils, methods, dismo, RCurl, magrittr, rgeos, soilDB (>= 2.0-1), leaflet (>= 2.0.0), leaflet.extras (>= 1.0.0), plotly (>= 4.8.0), DT, shiny (>= 1.1.0), shinycssloaders, shinydashboard, shinyWidgets
-RoxygenNote: 6.1.0
+RoxygenNote: 6.1.1
 Suggests: knitr,
     rmarkdown
 VignetteBuilder: knitr

NAMESPACE

@@ -2,6 +2,7 @@
 
 export(GetCDLFile)
 export(GetCDLValue)
+export(GetSDLValue)
 export(TileinPoly)
 export(cdlpal)
 export(runTool)

R/GetCDL.r

@@ -71,3 +71,33 @@ GetCDLValue <- function(year, lon, lat){
 
   return(list(value = value, category = category, color = color))
 }
+
+#' Get SDL point
+#'
+#' Get soil point information by longitude and latitude in WGS84.
+#'
+#' @param lon longitude in WGS84
+#' @param lat latitude in WGS84
+#' @return A list with the soil musym, mukey, muname, muacres
+#' @examples
+#' ## not run
+#' # GetSDLValue(-93.65, 42.03)
+#' @export
+#' @seealso \code\link{GetCDLValue}
+GetSDLValue <- function(lon, lat){
+  ## lon, lat: longitude and latitude in WGS84
+  pt <- matrix(c(lon, lat), nc = 2, byrow = T)
+  circ <- dismo::circles(pt, d = .1, lonlat = TRUE)
+  p <- rgeos::writeWKT(circ@polygons)
+  q <- paste0("SELECT musym, mukey, muname, muacres
+              FROM mapunit
+              WHERE mukey IN (
+              SELECT * from SDA_Get_Mukey_from_intersection_with_WktWgs84('", p, "')
+              )")
+  qres <- soilDB::SDA_query(q)
+  if(nrow(qres)>1) {
+    warning(sprintf("%.0f soil mapunits are found, choose the first one", nrow(qres)))
+    qres <- qres[1,]
+  }
+  qres
+}

README.md

@@ -26,6 +26,12 @@ help(GetCDLFile)
 help(GetCDLValue)
 ```
 
+- To fetch SDL data by pointwise coordinate
+
+```r
+help(GetSDLValue)
+```
+
 - CDL color scheme and palette:
 
 ```r

vignettes/introduction.Rmd

@@ -0,0 +1,65 @@
+---
+title: "Visualize soil and crop data and their overlay"
+author: "Xiaodan Lyu"
+date: "`r Sys.Date()`"
+output: rmarkdown::html_vignette
+vignette: >
+  %\VignetteIndexEntry{Vignette Title}
+  %\VignetteEngine{knitr::rmarkdown}
+  %\VignetteEncoding{UTF-8}
+---
+
+```{r setup, include = FALSE}
+knitr::opts_chunk$set(
+  collapse = TRUE,
+  comment = "#>"
+)
+```
+
+Vignettes are long form documentation commonly included in packages. Because they are part of the distribution of the package, they need to be as compact as possible. The `html_vignette` output type provides a custom style sheet (and tweaks some options) to ensure that the resulting html is as small as possible. The `html_vignette` format:
+
+- Never uses retina figures
+- Has a smaller default figure size
+- Uses a custom CSS stylesheet instead of the default Twitter Bootstrap style
+
+## Vignette Info
+
+Note the various macros within the `vignette` section of the metadata block above. These are required in order to instruct R how to build the vignette. Note that you should change the `title` field and the `\VignetteIndexEntry` to match the title of your vignette.
+
+## Styles
+
+The `html_vignette` template includes a basic CSS theme. To override this theme you can specify your own CSS in the document metadata as follows:
+
+    output: 
+      rmarkdown::html_vignette:
+        css: mystyles.css
+
+## Figures
+
+The figure sizes have been customised so that you can easily put two images side-by-side. 
+
+```{r, fig.show='hold'}
+plot(1:10)
+plot(10:1)
+```
+
+You can enable figure captions by `fig_caption: yes` in YAML:
+
+    output:
+      rmarkdown::html_vignette:
+        fig_caption: yes
+
+Then you can use the chunk option `fig.cap = "Your figure caption."` in **knitr**.
+
+## More Examples
+
+You can write math expressions, e.g. $Y = X\beta + \epsilon$, footnotes^[A footnote here.], and tables, e.g. using `knitr::kable()`.
+
+```{r, echo=FALSE, results='asis'}
+knitr::kable(head(mtcars, 10))
+```
+
+Also a quote using `>`:
+
+> "He who gives up [code] safety for [code] speed deserves neither."
+([via](https://twitter.com/hadleywickham/status/504368538874703872))