Problem
Each tree photo is tagged with a location. However, the Lat and Long based geo locations have anomalies on a number of different phones. In a tracking session, it is common for a phone to have a number of accurate points and one or two points that are tagged with inaccurate locations.
Example Problem
Tree id 3491297 was given a random location by the phone's GPS, and has subsequently been manually flagged for being located in the ocean.
The user tracks 4 trees.
Tree #4, Time Stamp: 14:45:03, POINT (-13.275777666666666 8.484414333333332)
Tree #3, Time Stamp: 14:41:32, POINT (-13.275915666666666 8.484348333333333)
Tree #2, Time Stamp: 14:40:03, POINT (-13.250369000000005 8.014978000000003)
Tree #1, Time Stamp: 16:39:00, POINT (-13.277494999999998 8.482369)
Possible Solutions 1
Review location data and time stamped data.
Use time and distance calculations between points to identify anomalies.
Flag the points that are in the incorrect location.
For example:
Distance between #2, #3 and #4 is a distance of about 27km covered in 63 seconds and 89 seconds.
The distance that someone can walk in Meters is: 1.788 meters per second, hence it would take about 5.9 hours to walk between the two.
The estimated geometric location is probably about half way between point #1 and #3.
Possible Solution 2
Compare locations with track files
Supporting data:
Time stamp
Geo Location
Track File
Deliverable: Scrubbed geo location data
Flag any data point that has traveled faster than a fast walk in a "tracking session"
Flag any specific devices that this occurs on.
Create a airflow script that runs periodically to population the Estimated Geometric Location to correct the flagged data point based on proximity to sequential data points.
Problem Each tree photo is tagged with a location. However, the Lat and Long based geo locations have anomalies on a number of different phones. In a tracking session, it is common for a phone to have a number of accurate points and one or two points that are tagged with inaccurate locations.
Example Problem
Tree id 3491297 was given a random location by the phone's GPS, and has subsequently been manually flagged for being located in the ocean.
The user tracks 4 trees. Tree #4, Time Stamp: 14:45:03, POINT (-13.275777666666666 8.484414333333332) Tree #3, Time Stamp: 14:41:32, POINT (-13.275915666666666 8.484348333333333) Tree #2, Time Stamp: 14:40:03, POINT (-13.250369000000005 8.014978000000003) Tree #1, Time Stamp: 16:39:00, POINT (-13.277494999999998 8.482369)
Possible Solutions 1
For example: Distance between #2, #3 and #4 is a distance of about 27km covered in 63 seconds and 89 seconds. The distance that someone can walk in Meters is: 1.788 meters per second, hence it would take about 5.9 hours to walk between the two.
The estimated geometric location is probably about half way between point #1 and #3.
Possible Solution 2 Compare locations with track files
Supporting data:
Deliverable: Scrubbed geo location data
Required Resources: