All versions of The Photographer’s Ephemeris use a standard form of URL. You can construct your own URLs (e.g. via a scripting tool or by manually editing the address in your browser) and use them freely – they’ll open in the web or iOS app as normal.
Standard Example
Here’s an example:
In this example, the parameters are used as follows:
| Parameter | Value | Usage |
|---|---|---|
| ll | 63.939897,-17.369803 | Red map pin location. Latitude, longitude coordinate pair in decimal degrees. Negative longitude is west. |
| center | 63.9586,-17.3145 | Centre of map. Latitude, longitude coordinate pair in decimal degrees. Negative longitude is west. |
| z | 9 | Zoom level. Value between 0 and 21 (maximum value may be lower with certain map types selected) |
| spn | 0.64,3.09 | Span. Decimal degree pair showing latitude and longitude span. Equivalent to zoom level. Use either. |
| dt | 2017-01-25T17%3A04%3A00.000Z | Date/time. Date and time in ISO 8601 format to millisecond precision. ‘%3A’ is the URL-encoded form of ‘:’ |
| sll | 63.972628,-17.052924 | Secondary pin location (optional). Latitude, longitude coordinate pair in decimal degrees. Negative longitude is west. |
Example showing building heights
Advanced Example
A more advanced example that includes building heights and footprint sizes:
Here’s a list of the parameters not mentioned above:
| Parameter | Value | Usage |
|---|---|---|
| sh | 5.00 | Primary object height in metres. e.g., the height of the camera above the ground |
| ch | 30.00 | Secondary object height in metres. e.g., the height of a building |
| sw | 10 | Building footprint in metres at primary pin |
| cw | 60 | Building footprint in metres at secondary pin. |
URL Parameters for Visual Search
The following URL parameters are reserved for future use with the Visual Search function.
| Parameter | Example | Usage |
|---|---|---|
| vsaa | vsaa=124.52,4.12,2,1 | Azimuth, altitude target. Comma-separated az/alt target followed by az/alt tolerance, all in degrees |
| vsaltp | vsaltp=false | Altitude priority. Determines whether the search interpolates for altitude (true, default) or azimuth (false) |
| vsd | vsd=15811200 | Search duration. Search period length, in seconds, from the app-selected date/time (use the ‘dt’ param to set the date/time) |
| vsr | vsr=false | Range mode. Range mode (true, default) or single target mode (false). In Range Mode, the search checks for the target body crossing the bounds of the az/alt region specified by the ‘vsaa’ parameter. In Single Target Mode, we interpolate the priority. |
| vsb | vsb=moon | Body. ‘sun’, ‘moon’, or ‘gc’ (galactic center). The body of interest. |
| vsa | vsa=-1 | Disk alignment. -1, 0, or 1. For bodies with known semidiameter (sun, moon), specifies whether the body should be aligned using the bottom (-1), centre (0, default), or top (+1) of the disk |
Visual Search Filters
Visual Search Filters can be encoded in the URL using the ‘vsf’ parameter, as follows:
vsf=b:[body]|p:[property]|v:[value_range]
where:
- body: sun, moon or gc
- property: az (azimuth), alt (apparent altitude), ill (illuminated fraction), wax (waxing), sd (semidiameter)
- value_range: comma-separated minimum and maximum values, e.g. 90,100 for azimuth (degrees), 0.95,1 for the Moon’s illuminated fraction, 0,0 for waxing = false or 1,1 for waxing = true
The ‘vsf’ parameter can specify multiple filter conditions using semicolon separation, e.g.,
vsf=b:moon|p:ill|v:0.95,1;b:sun|p:alt|v:-6,0
The example requires the Moon’s disk to be > 95% illuminated and for the Sun to be between 6 and 0 degrees below the horizon (i.e. civil twilight).
