IDL 8.0 & Update on IDL Development for HDF

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IDL 8.0 & Update on IDL Development for HDFBeau Legeer – Director Product Management (ITT-VIS)

September 30, 2010

HDF & HDF-EOS Workshop XIV

Visual Information Solutions

IDL 8.0 Goals

• Fine tuned the IDL application so it is “simple-to-drive” • With emphasis on the ad-hoc scientist user

• Major IDL language enhancements that are intuitive• New control features, core data types and modern scripting syntax

• Powerful graphics that are modern and easy-to-use• The best of direct graphics, object graphics and iTools

• Redesigned the Help to make it easier to learn IDL • Focus on tasks and “how to”

• Backward compatibility for existing code


Simple UI


Powerful Graphics


Redesigned Help


Major Language Enhancements


Graphics Functions & Dot Syntax

Creation – Uses a functional interface

myPlot = PLOT(myData)

Property Access – Uses a structure notation

myPlot.color = “yellow”

background = myPlot.background_color

Access Elements via Stringsaxis = myPlot.xaxisaxis.title = “Number of Farms”allAxes = myPlot[“* axis”] ; return all axes - wild card searches


New Graphics Functions

• Plot

• Barplot

• Errorplot

• Polarplot

• Plot3D

• Image

• Contour

• Surface

• Map

• Mapgrid

• Mapcontinents

• Legend

• Colorbar

• Widget_Window

• Vector

• Streamline

• Text

• Polygon

• Polyline

• Axis

• Ellipse


New Graphics

• Native look & feel to the graphics window

• Intuitive toolbar with interactive controls for the graphics

• Programmatic control that is easy to understand for the direct graphics user

• Cylindrical Equal Area map projection& other map improvements

• New symbols for object graphics

• PDF output from new graphics & object graphics

A Clean UI With Powerful Graphics


Language Features

!NULL • Simplifies a complex, confusing operation. Other uses:

• Comparison with undefined variables or null objects/pointers• Structure concatenation• Assign to variables or function results to free memory

A = [ ] ; or !NULL or { }

For i=0, 100 do begin

A = [A, getData()]

Endfor

Garbage Collection • Automatic object/pointer deletion means user no longer needs to

keep track of objects/pointers

Features of Modern Languages


Language – List & Hash

Methods to manage IDL variables of different types together• Arrays demand same types for each element

List• Combine any IDL type together in a single data type

L1 = LIST(‘spectrum', 5, 2, [1,2,3], LIST(1,2))

L1[0] = ‘Hello’

myVar = L1[0]

Hash (Dictionary) • Combine any IDL type together. Elements referenced via a key

H1 = HASH(‘dog', 100, ‘pig’, 200, ‘data’, findgen(100))

myVar = H1[“dog”]

H1[“mykey”] = ‘Hello’


Other Language Features

Control Statement• Addition of a “For Each” operator

FOREACH element, variable do begin print, element

ENDFOREACH

New Behavior• Negative Array Indices – “Wrap-around” the end of an array

A[ 0 : -1 ] ; goes from the first element (0) to the last element (N-1)A[ -3 : 0 : -1 ] ; goes from element N-3 down to element 0


Language – Operator Overloading

Perform a specific object method when an operator is performed on that object

Example: Combining the values of two “length objects” to return a new value

Current Syntax:

With Operator Overloading: Operator overloading allows you to hide this operation. Resulting in a normal statement:

The operation is placed in a method that is called when the “+” operator is used on the object:

FUNCTION idl_length::_overloadPlus, lenA, lenB

END

length = a->GetLength() + b->GetLength()c = obj_new(‘idl_length’, length) ;; make new object

length = a->GetLength() + b->GetLength()return, obj_new(‘idl_length’, length) ; make new object

Advanced Feature

c = a + b


What’s Overloadable

EQ NE GE GT LE LT

+ – * /

[ ] left [ ] right

NOT AND OR XOR

~ ^ mod

< >

# ##

&& ||

Help, Print

SIZE, N_ELEMENTS

FOREACH

“.” is Get/SetProperty

Just inherit from IDL_Object


Language – Objects Before & After 8.0

Create & Destroy

myObject = OBJ_NEW(‘MyClass’)

OBJ_DESTROY, myObject

Properties:

myObject->SetProperty,color=[255,0,0]

myObject->GetProperty, color=myColor

Calling Methods:

myObject->MyMethod, a, b, c

Key Points

• Strange syntax, difficult to learn

Create

myObject = MyClass( )

myObject.Cleanup

Properties:

myObject.color = ‘red’

myColor = myObject.color

Calling Methods:

myObject.MyMethod, a, b, c

Key Points

• Standard, intuitive syntax

IDL 7.0 IDL 8.0

A Simple Object Interaction Layer


IDL 8.0 Summary

• Fine tuned the IDL application so it is “simple-to-drive”

• Major IDL language enhancements that are intuitive

• Powerful graphics that are modern and easy-to-use

• Redesigned the Help to make it easier to learn IDL

• Backward compatibility for existing code

IDL 8 w/HDF5 demo

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HDF, netCDF & CDF Support in IDL 8.0

• HDF5 1.8.4

• netCDF 4.1

• CDF 3.3

• HDF-EOS 2.8 • Is the market for HDF-EOS5 growing?

• HDF 4.2r3

Are there more recent significant fixes?

HDF, HDF5, HDF-EOS future in IDL

• Continue to update library versions

• Incorporation of HDF-EOS5 based on demand

• Visual data browsing for all IDL Scientific Data Formats• Implement a Common Data Model• Integration directly with IDL Workbench and Language

• Incorporation of IDL 8.0 language enhancements to Scientific Data Formats• Easy to use object syntax for simple programmatic access• Reduce level of procedural calls• “Drill into” HDF objects programmatically

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Thank You!

Beau Legeer – Director of Product Management ITT-VIS

[email protected]

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Technology

IDL 8.0 & Update on IDL Development for HDF