barryrowlingson

###
### tach (c) Barry Rowlingson, 2012, pronounced like "tash"
###
### tach("file.R") will source that file into an environment and
### put it on the search path, thus including any function
### definitions without polluting your GlobalEnv
###
### retach() will scan your search path for any tach'ed files and
### if they have been modified since they were loaded they'll be
### re-tached.

barryrowlingson

require(rgeos)
require(sp)

makeRect <- function(origin, l1, l2, angle){
  sa = sin(angle)
  ca = cos(angle)
  x=origin[1] + c(0,l1*ca,l1*ca-l2*sa,-l2*sa,0)
  y=origin[2] + c(0,l1*sa,l1*sa+l2*ca,l2*ca,0)
  return(SpatialPolygons(list(Polygons(list(Polygon(cbind(x,y))),"Rectangle"))))
  return(cbind(origin[1]+x,origin[2]+y))

barryrowlingson

select TagName, 
       avg(cast(ResponseTime as bigint)) as Average,
       stdev(cast(ResponseTime as bigint)) as StandardDev
from 
  (SELECT
         Questions.CreationDate, 
         Questions.Title, 
         Tags.TagName,
         Answers.CreationDate as ResponseDate,
         datediff(minute, Questions.CreationDate, 

barryrowlingson

# Author: Joona Lehtomäki <[email protected]>
# Updated: 13.11.2011
# Version: 0.0.1

if (!require("rgdal")) {
	install.packages("rgdal")
}

if (!require("raster")) {
	install.packages("raster")

barryrowlingson

# You want to show users the code to make a plot.
# BUT you dont want to show them the png() function call you used to make the plot
# for your documentation. 
#
# dexy doesn't. You have to open/close the graphics device in your code:

### @export "graph"
png("plot.png")
plot(c(1,2,3), pch=19, col="purple")
dev.off()

barryrowlingson

abuff <- function(f, percent, precision, maxsteps = 20){
    require(rgeos)
    A0 = gArea(f)

    targetA = A0 + A0 * (percent/100)
    e = bbox(f)
    w0 = 0
    w2 = diff(e[1,])/10 # initial w

    ## initial expansion until we pass the solution:

barryrowlingson

###
### superclassing is nice
###

require(dplyr)
require(testthat)

set.seed(310366)
classes = c("thingy","data.frame")

barryrowlingson

# load an object 'name' from a .RData file 'file'.
# eg
# x1 = loadFrom("foo.RData","x")
# x2 = loadFrom("bar.RData","x")
#
# useful when you want to load from two or more files with objects with the same name and
# load(file) would stomp on the second one.

loadFrom=function(file, name){e=new.env();load(file,env=e);e[[name]]}

barryrowlingson

## make a data frame with a new class

d=data.frame(x=1:10,y=rnorm(10))
class(d)=c("foo","data.frame")

class(d)
## [1] "foo"        "data.frame"

## ordinary subsetting and subset preserve us:
##

barryrowlingson

<!DOCTYPE connections>
<qgsWMSConnections version="1.0">
    <wms ignoreGetMapURI="true" smoothPixmapTransform="false" dpiMode="7" password="" ignoreGetFeatureInfoURI="false" referer="" username="" url="http
://218.244.250.80:8080/erdas-apollo/coverage/CGLC" invertAxisOrientation="false" ignoreAxisOrientation="false" name="China Land Cover"/>
</qgsWMSConnections>