Subject: Marine Geospatial Ecology Tools (MGET) help
Text archives
| From: | "Jason Roberts" <> |
|---|---|
| To: | '程宛華' <> |
| Cc: | <> |
| Subject: | RE: [mget-help] The problem of extracting ArcGIS rasters from the HYCOM global ocean model's 4D netCDFs |
| Date: | Thu, 17 Oct 2013 10:18:09 -0400 |
Dear Lavinia, I’m terribly sorry but I have stopped maintaining that HYCOM script. MGET now includes a tool for downloading HYCOM directly from their OPeNDAP server and creating ArcGIS-compatible rasters. See here. The advantages of the new tool compared to the old script: · It is much easier to use. · You don’t have to download data yourself. · Because it uses OPeNDAP which allows the downloader to specify a spatial extent, it is much faster and requires less storage because MGET can obtain just what you need for the spatial extent, rather than global files. The disadvantages: · The new tool only retrieves data for the region of the HYCOM tri-pole grid that is in Mercator projection, which is latitudes 47 N to 66 S. This is because at higher latitudes HYCOM uses coordinate systems and grid-cell spacings that cannot be represented in ArcGIS. If you need data at higher latitudes, the new tool cannot do it, with one exception: it has an option to allow retrieval of data between 47 N and 60 N using an interpolation technique. · HYCOM used to offer data through their OPeNDAP server starting in November 2003, but recently they deleted all data from that server prior to September 19, 2008. They may still offer netCDF files from their FTP server for data prior to that date. The HYCOM team says that they are preparing a new dataset that will extend from late 1992 to the present day, using the latest algorithms. This dataset will have a geographic projection with square cells and go from 80 N to 80 S. This entire grid should be representable in ArcGIS. When they release that product, we will update MGET to use it instead of the existing GLBa0.08 product. Unfortunately the last ETA I heard for the new product was “late 2014”. If that is correct then we will have to wait a year for HYCOM data prior to 2008 to be conveniently accessible. I am not sure why they deleted the data from 2003-2008 if the replacement data will not be available for a year. My guess is they needed to free up space on their server and optimize their OPeNDAP software. They have suffered some server stability problems over the last six months. I hope that helps, Jason From: 程宛華 [mailto:] To someone whom may be concerned, My name is Wan-Hwa Cheng. I am a Master student in University of Central Florida now. Now I am using the map that I downloaded from HYCOM to analysis my data, but when I follow the step you post online, it couldn't work. The result shows in attachment. I am wondering could you please help me solve this problem? Besides, my windows system is Windows 8. Thank you!
Lavinia Cheng M.S. Student Geospatial Analysis and Modeling of Ecological Systems (GAMES) Lab Department of Biology University of Central Florida |