[dave_m]

Update: OmniGraphSketcher for iPad 1.5 is now available via the iTunes App Store!

Earlier this week we submitted OmniGraphSketcher for iPad 1.5 to the App Store. OmniGraphSketcher for iPad 1.5 introduces more powerful ways to visualize your data and ideas. Logarithmic axes let you focus on multiples of change with all of the flexibility and customizability you'd expect in OmniGraphSketcher. New support for double precision, scientific notation, and significant digits now allows you to make accurate, readable graphs spanning hundreds of orders of magnitude. We've also made many improvements to graph editing, document browsing, and the inspector. Read on for details.

• Logarithmic Axes
  • Lin-Log and Log-Log: OmniGraphSketcher for iPad now supports logarithmic scales on either or both axes. Simply select the axis you wish to adjust and open the inspector to switch between linear and logarithmic options. Dragging, nudging, snapping, sketch recognition, axis manipulation, importing, exporting, scale-to-fit, etc. have all been updated to work as you'd expect.
    
  • Double precision: To accommodate data sets that span many orders of magnitude, axes and data points now support up to 13 significant digits, and they can hold values as large as 10^300.
    
  • Flexible: OmniGraphSketcher's logarithmic axes support any range of values (they do not need to begin and end at powers of 10). The only exception is that the number zero is mathematically impossible on a logarithmic scale, so the min/max values must be both more than zero or both less than zero. OmniGraphSketcher will automatically fix any such issues when switching to a logarithmic axis and will prevent you from accidentally setting parameters that are mathematically undefined.
    
  • Line interpolation: Lines in OmniGraphSketcher connect two or more data points as smoothly as possible. That means when you switch between linear and logarithmic scales, intermediate points on the line do not necessarily represent the same values. To accurately maintain the shape of a line, tap and hold on it, then choose "Interpolate." This will sample along the vertical grid lines (x-values). All of those samples will maintain their position, allowing you to see how each part of the shape adjusts between linear and logarithmic space. For example, an interpolated straight line in linear space becomes an exponential curve in logarithmic space.
    
  
  
• Tick Labels
  • Scientific notation: Both linear and logarithmic axes now automatically use scientific notation ("1.23 x 10^45") when values get very large or very small. On logarithmic scales, simplified powers of ten are used when possible ("10^9"). You can edit these values or enter new data points by using the shortened "E" notation: "1.23E45" or "6E-7". There are also new controls in the inspector to let you override the automatic scientific notation settings.
    
  • Smarter label spacing: When there is not enough room to label every tick mark, tick labels are now always evenly spaced (skipping tick marks in multiples of two, five, or ten). On logarithmic axes, tick marks representing powers of ten are most likely to be labeled.
    
  • Major/minor tick marks: Where there are at least 5 tick marks between tick labels, OmniGraphSketcher now automatically uses longer and shorter tick marks to distinguish between labeled ticks (long) and unlabeled ticks (short). Thanks to these improvements, automatic tick spacing is now 1 in more cases, allowing more easily understandable scales.
    
  • Significant digits: Tick labels (and everything else in the app that displays numeric data values) now choose an appropriate number of significant digits based on the axis ranges. For example, an axis spanning 0 to 100 will display up to four significant digits ("1.234" or "93.47"); whereas an axis spanning 842 to 843 will use up to six significant digits ("842.551"). This is just for display; all data points are stored with full precision.
    
  
  
• Document Picker
  • You can now sort documents by date or by name.
    
  • You can quickly scan through your documents using the new scrubber bar at the bottom of the screen.
    
  • A new button in the Import popover lets you retrieve any of the sample documents that came with OmniGraphSketcher.
    
  
  
• Miscellaneous
  • The inspector popover has a new lighter-colored look, and it scrolls to reveal more controls.
    
  • You can now snap text labels onto points.
    
  • The return key now confirms new values in tick labels instead of inserting a carriage return.
    
  • Bold, italic, and underline buttons now work as expected when multiple text labels are selected.
    
  • A single tap inside the text editor now automatically positions the cursor at the beginning or end of words, and a triple tap selects the whole paragraph.
    
  • Fixed an issue that prevented the text editor from accepting Korean characters.
    
  • Accidental new labels now disappear if you do not edit the default "Label" text.
    
  • OmniGraphSketcher now uses the faster hardware-accelerated screen sharing available on iPad 2.
    
  • Grid lines now adjust to the nearest pixel so that they look sharper on-screen.
    
  • When importing data, OmniGraphSketcher now chooses even better automatic axis ranges.
    
  • Graph margins now take into account any arrowheads on the ends of axes.
    
  • Lines with straight segments at sharp angles now have gentler, rounded joints.
    
  • Smaller fixes and improvements.