Files
photoprism/pkg/clean/gps.go
2025-04-19 16:04:44 +02:00

141 lines
3.5 KiB
Go

package clean
import (
"fmt"
"strings"
"github.com/photoprism/photoprism/pkg/geo"
"github.com/photoprism/photoprism/pkg/txt"
)
// GPSBoundsDefaultPadding specifies the default padding of the GPS coordinates in meters.
const GPSBoundsDefaultPadding = 5.0
// GPSBounds parses the GPS bounds (Lat N, Lng E, Lat S, Lng W)
// and returns the coordinates with default padding.
func GPSBounds(bounds string) (latN, lngE, latS, lngW float64, err error) {
return GPSBoundsWithPadding(bounds, GPSBoundsDefaultPadding)
}
// GPSBoundsWithPadding parses the GPS bounds (Lat N, Lng E, Lat S, Lng W)
// and returns the coordinates with a custom padding in meters.
func GPSBoundsWithPadding(bounds string, padding float64) (latN, lngE, latS, lngW float64, err error) {
// Bounds string not long enough?
if len(bounds) < 7 {
return 0, 0, 0, 0, fmt.Errorf("no coordinates found")
}
// Trim whitespace and invalid characters.
bounds = strings.Trim(bounds, " |\\<>\n\r\t\"'#$%!^*()[]{}")
// Split bounding box string into coordinate values.
values := strings.SplitN(bounds, ",", 5)
found := len(values)
// Return error if number of coordinates is invalid.
if found != 4 {
return 0, 0, 0, 0, fmt.Errorf("invalid number of coordinates")
}
// Convert coordinate strings to floating point values.
latNorth, lngEast, latSouth, lngWest := txt.Float64(values[0]), txt.Float64(values[1]), txt.Float64(values[2]), txt.Float64(values[3])
// Latitudes have a valid range of +90 to -90 degrees.
if latNorth > 90 {
latNorth = 90
} else if latNorth < -90 {
latNorth = -90
}
if latSouth > 90 {
latSouth = 90
} else if latSouth < -90 {
latSouth = -90
}
// Make sure latSouth is smaller than latNorth.
if latSouth > latNorth {
latNorth, latSouth = latSouth, latNorth
}
// Longitudes have a valid range of -180 to +180 degrees.
if lngEast > 180 {
lngEast = 180
} else if lngEast < -180 {
lngEast = -180
}
if lngWest > 180 {
lngWest = 180
} else if lngWest < -180 {
lngWest = -180
}
// Make sure lngWest is smaller than lngEast.
if lngWest > lngEast {
lngEast, lngWest = lngWest, lngEast
}
// Calculate the latitude and longitude padding in degrees.
dLat, dLng := geo.Deg((latNorth+latSouth)/2.0, padding)
// Return the coordinates of the bounding box with padding applied.
return latNorth + dLat, lngEast + dLng, latSouth - dLat, lngWest - dLng, nil
}
// GPSLatRange returns a range based on the specified latitude and distance in km, or an error otherwise.
func GPSLatRange(lat float64, km float64) (latN, latS float64, err error) {
// Latitude (from +90 to -90 degrees).
if lat == 0 || lat < -90 || lat > 90 {
return 0, 0, fmt.Errorf("invalid latitude")
}
// Approximate range radius.
r := km * 0.75
// Approximate longitude range,
// see https://en.wikipedia.org/wiki/Decimal_degrees
dLat, _ := geo.DegKm(lat, r)
latN = lat + dLat
latS = lat - dLat
if latN > 90 {
latN = 90
}
if latS < -90 {
latS = -90
}
return latN, latS, nil
}
// GPSLngRange returns a range based on the specified longitude and distance in km, or an error otherwise.
func GPSLngRange(lat, lng float64, km float64) (lngE, lngW float64, err error) {
// Longitude (from -180 to +180 degrees).
if lng == 0 || lng < -180 || lng > 180 {
return 0, 0, fmt.Errorf("invalid longitude")
}
// Approximate range radius.
r := km * 0.75
// Approximate longitude range,
// see https://en.wikipedia.org/wiki/Decimal_degrees
_, dLng := geo.DegKm(lat, r)
lngE = lng + dLng
lngW = lng - dLng
if lngE > 180 {
lngE = 180
}
if lngW < -180 {
lngW = -180
}
return lngE, lngW, nil
}