I introduce here an interface between GrADS and Matlab: the read_grads.m routine reads the GrADS control file and retrieves the variable from the binary file accordingly. As far as possible, the components of the GrADS Data Descriptor File (or control file) were implemented in this routine. The companion routine write_grads.m writes a variable in the Matlab workspace as a binary file, with the appropriate control file. Examples are given hereafter. Example: [data,header]=read_grads('filename.ctl',');% Reads only the header [data,header]=read_grads('filename.ctl','varname');% Reads the header and [data,header]=read_grads('filename.ctl','varname','z',[z1,z2],'lon',[lon1,lon2],'lat',[lat1,lat2],'t',[t1,t2]); [data,header]=read_grads('filename.nc','varname');% Extension of read_grads.m to NetCDF variables * data is a 4-D variable, with X/lon as the first dimension, Y/lat as second dimension, Z/lev as third dimension and time in fourth dimension. * header is a structure variable, which contains all relevant information from the GrADS control file. Dc Blue Digital Manual.

In particular, the header.XDEF and header.YDEF sub-structures contain information for plotting the variable. Header.XDEF.num is the number of X fields, and header.XDEF.vec the X coordinates. Further details can be seen from the dedicated page. This function has worked well for me when I use it to read in a binary file with 1 variable.

But, when I try to read in a multi-variable file, it fails. I get an error that: Warning: Data read-in interrupted at l=1458 and k=1 >In read_grads_test>read_var (line 1192) In read_grads_test (line 180) ans = Offset is bad - after end-of-file or last character written. The 'Offset is bad' error is related to the 'fseek' function.

I have tried to debug read_grads to figure out what is happening with no luck. The outcome of this error is that the data is read in, but the read-in stops after a certain number of timesteps. For example, the data might have 365 days, but the read-in stops after day 173. If anyone has any suggestions, please help me out. THank you, Matt.

This message: [. The fun part comes in writing the ctl file. But if you want to write the binary file on a little endian machine (say. And does not support a number of grads data file options: Using one ctl file,. Converting grads files to NetCDF from. How to write the first for. Handling GrADS (Gridded Datasets). The following is a simple script to read a binary file using the GrADS.ctl file as a guide.; Grads control file.

Since GrADS cannot easily perform high level data analysis techniques, (barring a few complicated workarounds) it may be useful to save data so it can be used with more advanced software. It might seem logical at times to simply skip GrADS in the all together, which is fine. However, I often find it easier to use GrADS as an intermediary step as it allows me to use only the data I need, and arrange the data as I see fit.

This tutorial will teach you how to save data using GrADS by guiding you through an example that will save latitude/longitude and monthly average surface temperature data from NCEP reanalysis into a.txt file. Okay, so as always we will need to start by opening the data file.