Updates to readlas

Kevin W. Hall, Gary F. Margrave

The CREWES Matlab toolbox contains a script called readlas that has long had the ability to read version 1.2 and version 2.0 Log ASCII Standard (LAS) files. A new Matlab class called las that can handle all LAS versions has been written. The constructor reads an entire LAS file into memory and splits it into a Matlab cell string array using regular expressions. The readlas script is now a wrapper that creates a new las object and returns version 2.0 inputs suitable for logedit and syngram regardless of the LAS version of the input file. Since logedit and syngram cannot handle the multiple log data sections or logs containing character data (eg. lithology) that are allowed in LAS 3.0 files, or more than ten logs effectively, readlas provides graphical user interface (GUI) windows that prompt users to pick which log data section they would like to work on, and decide which logs within that section they want to edit. It also replaces any log character data with log null (numeric) values. The original readlas (pre 2013) is still available in the toolbox as readlas_old.