Wednesday, January 25, 2012

The Atlas of Visual Complexity

Very cool dynamic cartograms for visualizing economic complexity:

Thursday, January 19, 2012

Surface Climate Data

I am consulting on a research project involving bridge decay. For this project we needed to locate a number of surface atmosphere chemical data (some sulfure oxides and chloride) as well as data on precipitation, snowfall, and min/max temperature.

Here are some sources we found:

Tuesday, January 17, 2012


NetCDF is a format well suited for environmental research given the inherent multi-dimensionality of the environment and environmental research topics. 

I have not worked much with NetCDF data, and recently ran into some trouble importing gridded bathymetric data sets (GEBCO) into ArcGIS.

When importing into ArcGIS I attempted to use Multidimension Tools > Make NetCDF Raster Layer.  This tutorial from Esri describes this procedure.  Unlike in the tutorial, default values were not populated for tool parameters, and as I was unable to ascertain these values, I could not run the tool.

My next option was to learn more about the data set from GDAL's gdalinfo command.  After recompiling with the netcdf libraries, I was able to run gdalinfo on the data set, but it returned a rather sparse result that did not illuminate any of the parameters that I needed.  This contrasts with the result show in the GDAL documentation for netcdf.

I then attempted to load NetCDF directly into ENVI and IMAGINE -- common geospatial image proecessing programs -- I could not load it successfully into either of these.

I was somewhat more successful with IDL.  IDL is able to read NetCDF and report on its structure. However, the commands for interacting with the results objects are unwieldy at best.  This is an option that requires more investigation.

The GMT use NetCDF as the native package format, and GEBCO and others seem to base their NetCDF format off of GMT's specifications.  The grdinfo command under GMT gives some information about the data set, but still nothing that can be used in ArcGIS.  This also requires more investigation, as there are many commands for working with NetCDF.

Finally the data set was able to be opened by GEBCO's specialized display software (which is produced by the data provider).

I will be adding more to this post as I learn more about NetCDF and perhaps the peculiarities of this particular data set ... why use open standards if you need a data provider created tool to open the data??