A321
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness
Airspace Violation All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Chart Or Publication; Human Factors
Departing RWY 13 on the LGA Whitestone climb we initiated the turn at 4.1 miles instead of the 2.5 miles as required. ATC informed us of this and we followed instructions to correct error. He was quite correctly agitated at our error. When we were planning for this non-RNAV departure we both correctly briefed the turn headings but somehow managed to read the distance from the Maspeth climb right above the Whitestone box. The Maspeth shares the initial 180 turn. I fly mostly west coast turns and don't get to LGA very often or would have remembered that the turn on the Whitestone is pretty quick. We followed all procedures; had all radios tuned properly; did the route check; but somehow both made the same mistake of reading the distance from the wrong departure. I think we read the 180 heading on the iPad; looked up at the heading select; back down the iPad but 1/4 inch too high and got the distance; then selected the VOR; then back to the iPad for the correct 040 heading.Looking at the iPad it is not totally implausible that the close proximity of the two climbs could lead to this happening. What is hard to fathom is that it would happen to two pilots on the same flight thus not getting caught. Not having been to LGA in a while caused me to very closely check and double check and I still missed it. Unfortunately making the turn at 4.1 put us almost in JFK airspace thus magnifying the error. Given the proximity of the print on the iPad; I plan to make the box big enough that only one climb at a time is visible so that it is not possible to read part of one and part of another.
At the gate we briefed what we thought was the LGA 5 Whitestone Climb. I as the pilot flying also put a ring around LGA at 4 DME and we had the DME set for LGA on both sides for the turn to 040. Both of us misread the departure and thought the turn to 040 was at 4.1 DME instead of the correct 2.5 DME. As we were climbing out on the 180 heading; I kept thinking it was taking longer than normal to start the turn to 040; but didn't fully realize our mistake until queried by the Controller. We were already in the turn by then; but started about 1.5 miles too late.	It took some looking to find how we made the mistake. The instructions for the Maspeth climb on the LGA 5 departure are on the line directly above the Whitestone climb (both have a 180 heading initially). With the plate zoomed in and scrolled to the right; we both individually looked at the incorrect DME.The plan view on this particular departure is very cluttered; requiring more vigilance in reading the text description. It would be nice if LGA had separate departures for each 'climb' instead of all of them on the same plate. With virtually unlimited storage for digital plates; maybe it is time to rethink the old ways of doing things and have separate procedures for each. This was totally my fault and my mistake. In the future; I will be more diligent and use the markup feature while zoomed out to avoid this mistake.
A321 flight crew reported a track deviation on the LGA Whitestone 5 SID; citing iPad chart clutter as contributing.