IDL Meteorology Bo M Dr Robert Dahni r

IDL – Meteorology – Bo. M Dr Robert Dahni r. dahni@bom. gov. au Bureau of Meteorology Melbourne AUSTRALIA 6 August 2001

IDL and Bureau of Meteorology l IDL used since 1993 l BMRC (research) l COSB (operations) l AIFS (major project) l Olympics (special event) l SSU (commercial)

IDL and Malaysian Meteorological Service (MMS) Upgrade l Bo. M (SSU) commercial project l IDL requirements for MMS upgrade l SSU implementation strategy l Background maps l IDL applications (demo) l Tips, techniques and resources l Work in progress …

IDL Requirements for MMS Upgrade Background maps – coastlines, political, topography l Interactive visualisation (GUI) – real-time meteorological data – server, workstation and/or PC – UNIX, PC X-Emulation, Windows l Product generation – assistant l Web graphics – image files l

SSU Implementation Strategy Get experienced IDL programmer l Write software requirements l Utilise existing AIFS/IDL applications l Develop prototype applications l Feedback, training and documentation l Operational implementation l Work in progress … l

Background Maps l l l l Global 1 -km topography GTOPO 30 (~1. 8 Gb) gettopo. pro -> binary file Textured fill topography maptopo. pro -> image file displaymap. pro -> window 2 CD’s of data 0 E - 180 E, 50 o. S - 50 o. N 180 W - 0 W, 50 o. S - 50 o. N

Background Maps (continued) Global variable-resolution coastlines (GSHHS) l map_gshhs. pro -> coastlines l U. S. Geological Survey “Coastline Extractor” l plot_boundaries. pro -> political l

IDL Applications (demo) OBSViewer – weather observations l NWPViewer – NWP model output l Map. Draw – drawing tool l GONO – marine model output l Streamline – product generation l Map. Grid – NWP web graphics l Map. Obs – observations web graphics l Work in progress … l

OBSViewer – weather observations

NWPViewer – NWP model output

Map. Draw – drawing tool

GONO – marine model output

Streamline – product generation

Map. Grid – NWP web graphics

Map. Grid (continued)

Map. Obs - observations web graphics

Tips, Techniques and Resources l l l l Re-utilise existing relevant code Check publicly available IDL code Write neat, re-usable procedures Development – IDL (Windows 2000) Implementation – Windows and/or UNIX Use Direct Graphics unless interactive 3 D Simple, flexible GUI design (non-resizable) Batch mode (use Z-buffer or Postscript)

Tips, Techniques and Resources (continued) l l l l Use both IDL 5. 3 and 5. 4 (or latest version) Parameterise image format (GIF or PNG) Use read/write_image (NOT read_gif) Support 8 - AND 24 -bit color (Color_Quan) device, get_visual_depth=visual_depth device, Decomposed=0, Retain=2 Use color names (FSC_Color) Split color table (data/drawing colors)

Tips, Techniques and Resources (continued) l l l Global 1 -km topography (GTOPO 30) Textured fill topography Use cylindrical map projection /cyl, /noborder, xmargin=0, ymargin=0 to overlay geo-referenced data Global coastlines (GSHHS) Political boundaries (Coastline Extractor) …

Tips, Techniques and Resources (continued) l Australian IDL website Graphics - IDL Image Gallery http: //www. metvis. com. au/graphics Robert Dahni’s IDL Web Pages http: //www. metvis. com. au/idl/ Links to publicly available IDL code and applications http: //www. metvis. com. au/idl_code. html Links to coastline, topography data sets http: //www. metvis. com. au/idl_resources. html l Updated links to IDL resources worldwide