NCEAS Scientific Computing: Solutions Center
The items on this page have been produced in response to questions and requests from NCEAS associates. Included are sample data bases, software applications, and analytical method demonstrations. They are available for download and re-use for non-commercial purposes.
NCEAS intends for these examples to provide a basis for Ecologists to use in developing (and sharing) new data sets, programs, and techniques.
Note: For other available ecological data sets See also the NCEAS and KNB Data Repositories.
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Use Cases: Concise demonstrations of geospatial data analysis techniques
R Analytical Environment
A comparison and demonstration of five R techniques for reading and displaying ESRI Shapefiles
Transform and export point locations From a GPS file
Download collected point locations from GPS, correct and convert to ESRI Shapefile, transform latitude/longitude into UTM coordintates, generate simple plots.
Point-in-Polygon assignment to point data set members
Associate points in a data set with the polygons in a second data set that surround them.
Sampling Vector Polygon Data Using Point Grid Overlay
Extract polygon attribute values at regular intervals using a point grid.
Compute Centroids (center of mass) for polygon data set in shape file format.
Demonstrates two different R programming approaches to generating the Convex Hull bounding a set of point locations.
Compute Convex Hull polygons for point data set
Demonstrates two different R programming approaches to generating the Convex Hull (inlcuding hull polygon areas) bounding a set of point locations.
Explore the relationships of spatially concident point and polygon data layers using R geospatial tools
Assign Nearest Neighbor points to a separate point data set
Input two geocoded point data sets from .csv files into the R environment, then assign to one of the data sets the geographically closest point locations from the second data set.
Aggregate spatial data polygons into larger polygons along with their descriptive attributes, using a spatial primary key
Calculate Regions-of-Interest (ROI) polygons for point data set members
Given a point data set AND a polygon data set whose members surround the point set members: 1) Compute the polygon areas; 2) assign each point its 'bounding polygon'; 3) calculate the convex hull bounding the point data set; 4) generate Region of Interest (ROI) polygons surrounding each point data set member
Produce high-quality maps for publication using R graphics
Generate various types of publication-quality maps using standard R graphics tools
How Map Projections Work: A Discussion
Discusses the geometric and algorithmic fundamentals behind the development of map projections
Integrate C language function into R with an R package
A step-by-step tutorial, including a complete, downloadable example, demonstrating the creation and use of an R package that calls a C function performing simple matrix calculations.
ESRI ArcMap GIS
ArcMap GIS: use mouse to point/click/extract image values from raster data layer (12 kb Pdf)
Change the Latitude/Longitude display units and extract single-pixel values using the mouse.
ArcMap GIS Overlay Polygon Coverage Generation (33 kb Pdf)
Create a Point Shape File attribute file by performing a series of Spatial Join operations.
ESRI ArcMap GIS Spatial Overlay Analysis (31 kb Pdf)
Use Polygon Shape Files to perform raster data set clipping operations
Interactively extract and save Arc Map GIS Shape File subset (9 kb Pdf)
Use the mouse to select and write a subset of existing ESRI Shape File to new Shapefile.
Case Studies: In-depth geospatial analysis examples derived from NCEAS associates' research projects
Data Acquisition and Analysis / R Analytical Environment
R Language Scripts for USA County Shape File Processing (8 mb ZIP file)
R Programming Language scripts used to produce the United States County Boundary and Centroid Shape Files. Good examples of using R to process ESRI Shape Files.
Acquire and process GRIB format GCM climate data files
Search for and download General Circulation Model (GCM) time series data In gridded Binary (GRIB) format. Import the data into the R programming environment. Aggregate the individual monthly time series to generate long-term monthly average time series. Display the resulting images in R, ArcMap GIS, and MATLAB.
Locate, read and analyze NetCDF format climate data files
Search for and download NOAA/NCEP Reanalysis relative humidity time series data in NetCDF format. Import the data into the R programming environment and to explore the data.
High-level language programming
Optimize C Raster Processing code to use multiple CPUs and Shared Memory
Implements a 2-dimensional raster grid program coded using ANSI standard C++ and Message Passing Interface (MPI) and Unix shared memory functions.
MATLAB Analytical Environment
Read and Analyze NetCDF format Climate Model data sets using MATLAB
Search for and download General Circulation Model (GCM) simulation data sets stored in NetCDF format. Use MATLAB script to extract and explore the data set
ESRI / ArcMap GIS
ESRI ArcMap GIS tutorial: Map design and production for publication (1.9 MB Pdf)
Use Map Layout tools to design a three-panel global study area map.
Link to source for Global Land Cover map image used in the tutorial (34 MB .zip file).ESRI ArcMap GIS Digital Elevation Model (DEM) Analysis (16 MB Pdf)
Use Digital Elevation Models (DEM) and ArcMap GIS to compute and analyze habitat elevation zones.
Data import utilities for Microsoft Excel-format data files
Import MS Excel spreadsheet data into ArcMap GIS point shapefile (11 kb Pdf)
Import data in Excel Spreadsheet into an ArcMap GIS shapefile.
Import MS Excel spreadsheet data into SAS Data sets (1.8 MB Zip file)
Import data in Excel Spreadsheet into a SAS data set.
Geospatial Data Sets
Base United States County Boundary File (8.5 mb ZIP file)
Base 50-State polygon shapefile containing USA County outlines.
United States County Boundary File with centroids and US Census FIPS Codes (17 mb ZIP file)
Three ESRI-format shape files: US County boundaries,County boundaries with centroid lat/long and US Census Bureau FIPS codes, and US County centroids with FIPS Codes.