Data Science

• A much-hyped phrase, but effectively is about the application of statistics and machine learning to real-world data, and developing formalized tools instead of one-off analyses. Combines diverse fields to solve problems.

Data Science

What's a data scientist?

Data Science

Us geographic folks also rely on knowledge from multiple domains. We know that spatial is more than just an x and y column in a table, and how to get value out of this data.

Data Science Languages

Languages commonly used in data science:

R — Python — Matlab — Julia

We're a big Python shop, so why R?

R vs Python for Data Science

Why ?

• Powerful core data structures and operations
  • Data frames, functional programming
• Unparalleled breadth of statistical routines
  • The de facto language of Statisticians
• CRAN: 6400 packages for solving problems
• Versatile and powerful plotting

R Data Types

Data types you're used to seeing...

Numeric - Integer - Character - Logical - timestamp

R Data Types

Example source

Vector:

a.vector <- c(4, 3, 8, 7, 1, 5)

Matrix:

A = matrix(
    c(4, 3, 8, 7, 1, 5), # same data as above
    nrow=2, ncol=3, # what's the shape of the data?
    byrow=TRUE) # what order are the values in?

R Data Types

Data Frames:

• Treats tabular (and multi-dimensional) data as a labeled, indexed series of observations. Sounds simple, but is a game changer over typical software which is just doing 2D layout (e.g. Excel)

R Data Types

# Create a data frame out of an existing tabular source
df.from.csv <- read.csv("data/growth.csv", header=TRUE)

# Create a data frame from scratch
quarter <- c(2, 3, 1) 
person <- c("Goodchild", "Tobler", "Krige") 
met.quota <- c(TRUE, FALSE, TRUE)
df <- data.frame(person, met.quota, quarter) 

R> df
     person met.quota quarter
1 Goodchild      TRUE       2
2    Tobler     FALSE       3
3     Krige      TRUE       1

sp Types

Entity + Attribute model

Hadley Stack

• Hadley Wickham
• Developer at R Studio, Professor at Rice University
• ggplot2, scales, dplyr, devtools, many others

Statistical Formulas

fit.results <- lm(pollution ~ elevation + rainfall + ppm.nox + urban.density)

• Domain specific language for statistics
• Similar properties in other parts of the language
• caret for model specification consistency

Literate Programming

• packages: RMarkdown, Roxygen2
• Jupyter notebooks

Development Environments

• 
• née IPython
• R Tools for Visual Studio brand new

dplyr Package

Batting %.%
  group_by(playerID) %.%
  summarise(total = sum(G)) %.%
  arrange(desc(total)) %.%
  head(5)

Introducing dplyr

R Challenges

• Performance issues
• Not a general purpose language
• Lacks purely UI mode of interaction (e.g. plots must be manually specified)
• Programmer only. There is shiny, but R is first and foremost a language that expects fluency from its users

R — ArcGIS Bridge

• ArcGIS developers can create custom tools and toolboxes that integrate ArcGIS and R
• ArcGIS users can access R code through geoprocessing scripts
• R users can access organizations GIS' data, managed in traditional GIS ways

https://r-arcgis.github.io

R — ArcGIS Bridge

Store your data in ArcGIS, access it quickly in R, return R objects back to ArcGIS native data types (e.g. geodatabase feature classes).

Knows how to convert spatial data to sp objects.

Package Documentation

ArcGIS vs R Data Types

ArcGIS vs R Data Types

Access ArcGIS from R

Start by loading the library, and initializing connection to ArcGIS:

# load the ArcGIS-R bridge library
library(arcgisbinding)
# initialize the connection to ArcGIS. Only needed when running directly from R.
arc.check_product()

Access ArcGIS from R

Opening data has two stages, like data cursors:

• Open data source with arc.open
• Select with filtering with arc.select

Similar to using arcpy.da cursors

Access ArcGIS from R

First, select a data source (can be a feature class, a layer, or a table):

input.fc <- arc.open('data.gdb/features')

Then, filter the data to the set you want to work with (creates in-memory data frame):

filtered.df <- arc.select(input.fc, 
                          fields=c('fid', 'mean'),
                          where_clause="mean < 100")

This creates an ArcGIS data frame -- looks like a data frame, but retains references back to the geometry data.

Access ArcGIS from R

Now, if we want to do analysis in R with this spatial data, we need it to be represented as sp objects. arc.data2sp does the conversion for us:

df.as.sp <- arc.data2sp(filtered.df)

arc.sp2data inverts this process, taking sp objects and generating ArcGIS compatible data frames.

Access ArcGIS from R

Finished with our work in R, want to get the data back to ArcGIS. Write our results back to a new feature class, with arc.write:

arc.write('data.gdb/new_features', results.df)

Access ArcGIS from R

WKT to proj.4 conversion:

arc.fromP4ToWkt, arc.fromWktToP4

Interacting directly with geometries:

arc.shapeinfo, arc.shape2sp

Geoprocessing session specific:

arc.progress_pos, arc.progress_label, arc.env (read only)

Building R Script Tools

Building R Script tools

tool_exec <- function(in_params, out_params) {
  # the first input parameter, as a character vector
  input.features <- in_params[[1]]

  # alternatively, can access by the parameter name:
  input.input <- in_params$input_features
  print(input.dataset)
  # ... next, do analysis steps

  # this will be returned as the "Output Graphs" parameter.
  out_params[[1]] <- plot(results.dataset)
  return(out_params)
}

R ArcGIS Bridge Demo

• Details of model based clustering analysis in the R Sample Tools

How To Install

• Install with the R bridge install
• Detailed installation instructions

Where Can I Run This?

Where Can I Run This?

• Now:
  • First, install R 3.1 or later
  • ArcGIS Pro (64-bit) 1.1 or later
  • ArcGIS 10.3.1 or later:
    • 32-bit R by default in Desktop
    • 64-bit R available via Server and Background Geoprocessing
• Upcoming:
  • Conda for managing R environments

Other Sessions

• Integrating Open-source Statistical Packages with ArcGIS
• Python: Developing Geoprocessing Tools
• Harnessing the Power of Python in ArcGIS Using the Conda Distribution
• Python: Working with Scientific Data

R

Looking for a package to solve a problem? Use the CRAN Task Views.

Tons of good books and resources on R available, check out the RSeek engine to find resources for the language which can be difficult to locate because of the name.

R Packages by Hadley Wickham

Spatial R / Data Science

• An Introduction to Staistical Learning (PDF) website A free and accessible version of the classic in the field, Elements of Statistical Learning.

• Getting Started in Data Science

ArcGIS + R

• UC Plenary Demo: Statistical Integration with R
  • Demo of SSN: spatial modeling on stream networks
• Cam Plouffe (Esri CA) ran an R ArcGIS Workshop, covers materials in more depth.

Materials

Courses:

• High Performance Scientific Computing
• The Data Scientist's Toolbox

Books:

• Spatial Statistical Data Analysis for GIS Users Konstantin Krivoruchko (GA creator)
  • Too big to print. Tons of useful stuff, covers both R and ArcGIS extensively.

Packages

Clustering demo covers mclust and sp.

• Tree-based models, e.g. CART
• Time series data, e.g. Little Book of R

R ArcGIS Extensions

• R ArcGIS Bridge
• Marine Geospatial Ecology Tools (MGET)
  • Combines Python, R, and MATLAB to solve a wide variety of problems
• Geospatial Modeling Environment
  • An R flavored language for spatial analysis

Conferences

• useR! Conference
  • useR 2016 is being held at Stanford June 27-30
• Open Data Science Conference (ODSC)
  • Many happening around world, some upcoming ones:
  • ODSC East May 20-22 in Boston
  • ODSC West Nov 4-6 in Santa Clara

Outreach

• Resources and outreach -- connect the dots, want this to be outreach so we can build up more R + ArcGIS people who aren't as common as our core language folks.
• Future of the project, questions

Community

• Open source project, different ethos
• Contributions are the currency
  • That said, major uptake in the commercial space:
  • Microsoft R (bought Revolution Analytics); R Studio
• Our involvement:
  • Recently hosted a Space-time Statistics Summit
  • More soon

Thanks

• R team: Dmitry Pavlushko, Steve Kopp, Konstantin Krivoruchko; today's speakers
  • Contact Us
• Geoprocessing Team

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