IGC-SPY Metrics Reference

Key Terminology

Term	Description
Glide	A segment of straight flight between thermals
Track	Actual distance flown (every GPS fix)
True (T-)	Excludes tries (failed thermal attempts)
Tries	Failed thermal attempts (entered but abandoned)
Thermals	Successful thermal climbs
Orbit	One complete circle in a thermal
Netto	Vertical air mass movement (lift/sink)
STF	Speed To Fly - optimal speed for conditions
Stab	Stabilised - excludes entry/exit of thermal
_r, _l, _m	Right turn, Left turn, Mixed direction suffixes

Race Class Metrics

The Race class contains aggregate statistics for the entire race (start to finish).

Time Metrics

Metric	Field Name	Description	Calculation
Start Time	start_time	Time at race start	First fix after start
End Time	end_time	Time at race finish	Finish fix time
Race Time	race_time	Total race duration	end_time - start_time
Glide Time	glide_time	Time gliding (incl tries)	tglide_time + tries_time
True Glide Time	tglide_time	Time gliding (excl tries)	Direct measurement
Thermal Time	thermal_time	Time in thermals	Sum of all thermal times
Tries Time	tries_time	Time in failed attempts	Sum of all tries times
True Glide Time %	tglide_time_pct	% of race gliding	tglide_time / race_time * 100
Thermal Time %	thermal_time_pct	% of race thermaling	thermal_time / race_time * 100
Tries Time %	tries_time_pct	% of race in tries	tries_time / race_time * 100

Altitude Metrics

Metric	Field Name	Description	Calculation
Start Altitude	start_alt	Altitude at start	Start fix altitude
End Altitude	end_alt	Altitude at finish	Finish fix altitude
Race Altitude	race_alt	Net altitude change	end_alt - start_alt
Min Altitude	min_alt	Lowest point in race	Minimum of all fixes
Max Altitude	max_alt	Highest point in race	Maximum of all fixes
Glide Altitude	glide_alt	Alt change during glides (incl tries)	Sum of glide altitude changes
True Glide Altitude	tglide_alt	Alt change during glides (excl tries)	Sum excluding tries
Thermal Altitude	thermal_alt	Total alt gained in thermals	Sum of thermal gains
Thermal Lost Altitude	thermal_lost_alt	Alt lost while thermaling	Sum of negative changes in thermals
Tries Altitude	tries_alt	Alt change in tries	Sum of tries altitude
Tries Lost	tries_lost	Alt lost in tries	Sum of negative changes in tries
Avg Thermal Altitude	avg_thermal_alt	Average alt gain per thermal	thermal_alt / thermals_count
Avg Glide Altitude	avg_glide_alt	Average cruising altitude	Weighted average during glides

Distance Metrics

Metric	Field Name	Description	Calculation
Race Length	race_length	Point-to-point distance	distance(start_fix, finish_fix)
Track Length	track_length	Total path flown (excl thermals)	Sum of all glide segments
True Track Length	ttrack_length	Path flown (excl thermals & tries)	Sum excluding tries
Race Deviation %	race_deviation_pct	Extra distance from deviations	(ttrack_length / race_length - 1) * 100
Avg Glide Length	avg_glide_length	Average distance between thermals	race_length / glides_count

Count Metrics

Metric	Field Name	Description
Glides Count	glides_count	Number of glide segments
Thermals Count	thermals_count	Number of thermals used
Thermals Count R	thermals_count_r	Right-turning thermals
Thermals Count L	thermals_count_l	Left-turning thermals
Thermals Count M	thermals_count_m	Mixed-direction thermals
Tries Count	tries_count	Number of failed thermal attempts

Speed Metrics

Metric	Field Name	Description	Calculation
Race Speed	race_speed	Overall race speed	race_length / race_time
Glide Speed	glide_speed	Speed excluding thermal time	race_length / glide_time
True Glide Speed	tglide_speed	Speed excl thermals & tries	race_length / tglide_time
Track Speed	track_speed	Actual path speed (excl thermals)	track_length / glide_time
True Track Speed	ttrack_speed	Path speed excl tries	ttrack_length / tglide_time
Min Speed	min_speed	Minimum ground speed in glides	Minimum of glide segments
Max Speed	max_speed	Maximum ground speed in glides	Maximum of glide segments
Avg Thermal Speed	avg_thermal_speed	Average speed while circling	Weighted average in thermals
Avg STF	theory_avg_dolphin_stf	Theoretical optimal Speed To Fly	Calculated from conditions

Climb Rate Metrics

Metric	Field Name	Description	Calculation
Avg Thermals Climb	avg_thermals_climb	Average climb per thermal	thermal_alt / thermal_time
Avg Thermals Climb R	avg_thermals_climb_r	Right-turn thermal climb rate	Right thermals only
Avg Thermals Climb L	avg_thermals_climb_l	Left-turn thermal climb rate	Left thermals only
Avg Thermals Climb M	avg_thermals_climb_m	Mixed thermal climb rate	Mixed thermals only
Avg Orbits Climb	avg_orbits_climb	Average climb per orbit	Average of orbit climb rates
Avg Orbits Climb R	avg_orbits_climb_r	Right orbit climb rate	Right orbits only
Avg Orbits Climb L	avg_orbits_climb_l	Left orbit climb rate	Left orbits only
Avg Orbits Climb M	avg_orbits_climb_m	Mixed orbit climb rate	Mixed orbits only
Avg Tries Climb	avg_tries_climb	Climb rate in tries	tries_alt / tries_time

L/D (Lift/Drag Ratio) Metrics

Metric	Field Name	Distance	Altitude	Calculation
Glide LD	glide_ld	Point-to-point	Includes tries	-race_length / glide_alt
True Glide LD	tglide_ld	Point-to-point	Excludes tries	-race_length / tglide_alt
Track LD	track_ld	Every fix	Includes tries	-track_length / glide_alt
True Track LD	ttrack_ld	Every fix	Excludes tries	-ttrack_length / tglide_alt

Netto & Polar Metrics

Metric	Field Name	Description	Calculation
True Track Netto	ttrack_avg_dolphin_netto	Average netto (air mass)	Average of fix-by-fix netto values
True Track Avg Netto	ttrack_avg_block_netto	Weighted average netto	Block-style netto calculation
Sink at STF	sink_at_stf	Sink rate at theoretical STF	polar_sink_rate(netto, theory_avg_dolphin_stf)
Sink at TTrack Speed	sink_at_ttrack_speed	Sink rate at actual speed	polar_sink_rate(netto, ttrack_speed)
Density Alt % Gain	dens_alt_percent_gain	Performance gain from altitude	Based on air density

Leg Class Metrics

The Leg class contains the same metrics as Race but for individual task legs (between turnpoints).

All Race metrics apply to Leg, with these additional fields:

Metric	Field Name	Description
Leg ID	id	Leg number (1, 2, 3...)
Start Point	start_point	Turnpoint name at leg start
Finish Point	finish_point	Turnpoint name at leg end
Leg Time	leg_time	finish_fix.rawtime - start_fix.rawtime

Glide Class Metrics

The Glide class contains metrics for individual glide segments between thermals.

Time Metrics

Metric	Field Name	Description
Start Time	start_time	Entry time into glide
End Time	end_time	Exit time from glide
Glide Time	glide_time	Duration including tries
True Glide Time	tglide_time	Duration excluding tries
Tries Time	tries_time	Time spent in tries during glide

Altitude Metrics

Metric	Field Name	Description
Start Altitude	start_alt	Altitude at glide start
End Altitude	end_alt	Altitude at glide end
Glide Altitude	glide_alt	Altitude change (incl tries)
True Glide Altitude	tglide_alt	Altitude change (excl tries)
Tries Altitude	tries_alt	Altitude change in tries
Min Altitude	min_alt	Lowest point in glide
Max Altitude	max_alt	Highest point in glide

Distance Metrics

Metric	Field Name	Description
Glide Length	glide_length	Point-to-point distance
Track Length	track_length	Actual path distance
True Track Length	ttrack_length	Path distance excl tries
Tries Track Length	tries_track_length	Path distance in tries

Speed Metrics

Metric	Field Name	Description	Calculation
Glide Speed	glide_speed	Point-to-point speed	glide_length / glide_time
True Glide Speed	tglide_speed	P2P speed excl tries	glide_length / tglide_time
Track Speed	track_speed	Path speed	track_length / glide_time
True Track Speed	ttrack_speed	Path speed excl tries	ttrack_length / tglide_time
Min Speed	min_speed	Minimum ground speed
Max Speed	max_speed	Maximum ground speed

L/D Metrics

Metric	Field Name	Calculation
Glide LD	glide_ld	-glide_length / glide_alt
True Glide LD	tglide_ld	-glide_length / tglide_alt
Track LD	track_ld	-track_length / glide_alt
True Track LD	ttrack_ld	-ttrack_length / tglide_alt

Vario & Netto Metrics

Metric	Field Name	Description
Glide Vario	glide_vario	Sink rate (incl tries)
True Glide Vario	tglide_vario	Sink rate (excl tries)
True Track Netto	ttrack_avg_dolphin_netto	Air mass movement (netto)
True Track Avg Netto	ttrack_avg_block_netto	Weighted average netto
STF	stf	Speed To Fly for this glide
Sink at STF	sink_at_stf	Expected sink at STF

Thermal Class Metrics

The Thermal class contains metrics for individual successful thermal climbs.

Basic Info

Metric	Field Name	Description
ID	id	Thermal number (1, 2, 3...)
Direction	direction	Turn direction (R, L, M)
Orbit Count	orbit_count	Number of complete circles

Time Metrics

Metric	Field Name	Description
Start Time	start_time	Entry time into thermal
End Time	end_time	Exit time from thermal
Time	time	Total time in thermal

Altitude Metrics

Metric	Field Name	Description
Start Altitude	start_alt	Altitude at entry
End Altitude	end_alt	Altitude at exit
Altitude	alt	Net altitude gained
Lost Altitude	lost_alt	Altitude lost in sinking moments
Min Altitude	min_alt	Lowest point in thermal
Max Altitude	max_alt	Highest point in thermal

Speed Metrics (Ground Speed While Circling)

Metric	Field Name	Description
Min Speed	min_speed	Minimum ground speed
Max Speed	max_speed	Maximum ground speed
Avg Speed	avg_speed	Average ground speed
Stab Min Speed	stab_min_speed	Stabilised min speed
Stab Max Speed	stab_max_speed	Stabilised max speed
Stab Avg Speed	stab_avg_speed	Stabilised avg speed

Orbit Time Metrics

Metric	Field Name	Description
Min Orbit Time	min_orbit_time	Fastest orbit
Max Orbit Time	max_orbit_time	Slowest orbit
Avg Orbit Time	avg_orbit_time	Average orbit duration
Stab Min Orbit Time	stab_min_orbit_time	Stabilised min
Stab Max Orbit Time	stab_max_orbit_time	Stabilised max
Stab Avg Orbit Time	stab_avg_orbit_time	Stabilised average

Orbit Diameter Metrics

Metric	Field Name	Description
Min Diameter	min_diam	Smallest circle diameter
Max Diameter	max_diam	Largest circle diameter
Avg Diameter	avg_diam	Average circle diameter
Stab Min Diameter	stab_min_diam	Stabilised min
Stab Max Diameter	stab_max_diam	Stabilised max
Stab Avg Diameter	stab_avg_diam	Stabilised average

Climb Rate Metrics

Metric	Field Name	Description
Min Climb	min_climb	Minimum climb rate
Max Climb	max_climb	Maximum climb rate
Avg Climb	avg_climb	Average climb rate
Stab Min Climb	stab_min_climb	Stabilised min
Stab Max Climb	stab_max_climb	Stabilised max
Stab Avg Climb	stab_avg_climb	Stabilised average

Wind Metrics

Metric	Field Name	Description
Wind Direction	wind_dir	Estimated wind direction
Wind Speed	wind_speed	Estimated wind speed

Other

Metric	Field Name	Description
Track Length	track_length	Total distance flown in thermal

Orbit Class Metrics

The Orbit class contains metrics for individual circles within thermals.

Metric	Field Name	Description
ID	id	Orbit number within thermal
Direction	direction	Turn direction (R, L)
Start Time	start_time	Circle start time
End Time	end_time	Circle end time
Time	time	Circle duration
Start Altitude	start_alt	Altitude at start
End Altitude	end_alt	Altitude at end
Altitude	alt	Net altitude gain
Lost Altitude	lost_alt	Altitude lost in sinking moments
Lost Alt %	lost_alt_pct	% of gain lost
Track Length	track_length	Distance flown in orbit
Diameter	diam	Circle diameter
Min Speed	min_speed	Minimum ground speed
Max Speed	max_speed	Maximum ground speed
Speed	speed	Average ground speed
Vario	vario	Climb rate

Thermal Attempt (Tries) Class

The Thermal_attempt class extends Thermal with the same metrics, but represents failed thermal attempts that were abandoned.

Calculation Notes

Time Components

Race Time = Thermal Time + Glide Time
          = Thermal Time + (True Glide Time + Tries Time)

Distance Components

Track Length = TTrack Length + Tries Distance + Thermal Circle Distance
Race Length = Point-to-point distance (straight line)

Altitude Components

glide_alt = Altitude change during glides (including tries)
tglide_alt = Altitude change during glides (excluding tries)
thermal_alt = Altitude gained in thermals
tries_alt = Altitude gained/lost in tries

Stabilised vs Regular Metrics

• Regular: Includes all data from thermal entry to exit
• Stabilised (Stab): Excludes entry and exit phases, only measures steady-state circling

Direction Suffixes

• _r: Right-turning thermals only
• _l: Left-turning thermals only
• _m: Mixed (changed direction) thermals only

Database Storage Units

All values are stored in SI units:

Measurement	Unit
Distance	meters (m)
Speed	meters per second (m/s)
Altitude	meters (m)
Time	seconds (s) or HH:MM:SS string
Wing Loading	kg/m²
Climb Rate	m/s (vario)

The web interface converts these based on user preferences.

Delta Color Coding (h2h.php)

Color	Meaning
Green	Glider 1 better than Glider 2
Red	Glider 1 worse than Glider 2
Blue	Neutral/informational delta

Green = Better (positive is good)

Race Speed, all climb rates, all L/D ratios, netto values

Red = Better (positive is bad)

Tries Count, Tries Time, Sum of Alt Lost metrics