Location From Google Maps
From Stellarium Wiki
Here's a technique for determining your precise location using Google Maps and Topocoding.com.
The very short version (recommended):
- Use the Stellarium Location Helper, a Google Maps/Topocoding mash-up I've put online, and copy the data to the Stellarium Location dialog.
- There is no step 2 :-)
- (But see step 11 in the long, manual version below if you find that the Location dialog gives you a hard time.)
The short, manual version:
- Extract latitude and longitude from the Google Maps permalink URL (it is contained in the ll query parameter - that is two lower-case L's for latitude/longitude. The first number is the latitude in decimal notation, the second number is the longitude.)
- Use a tool such as the FCC latitude/longitude converter to convert decimal to degrees/minutes/seconds, replacing +/- signs with N/S (for latitude) or E/W (for longitude)
- Use topocoding.com to determine the altitude.
- Copy-and-paste the data into Stellarium's text fields
The long, manual version:
- Navigate to your location using Google Maps
- Open Google Maps in your browser (or open a localized version of Google Maps if you prefer, such as Google Maps Germany).
- Navigate to your location. For example, enter your address such as: 8-10 rue Mario Nikis, 75738 Paris Cedex 15, France
- When your location is in the center of the Google Maps display, copy the permanent URL of this location to the clipboard
- Find the hyperlink (blue, underlined text) labelled Link in the top right corner of the Google Maps page. It should have a symbol of a little chain next to it.
- Right-click that link and choose Copy Link Location (Firefox) or use the equivalent menu item in other browsers
- Paste the URL into a text editor
- Open a text editor such as TextEdit (Mac OS X), Notepad (Windows), or Kate (KDE).
- Use the text editor command to paste the URL - e.g. use the Edit->Paste menu item, or press Ctrl+V on Windows or Linux, or Cmd+V on Apple
- You should now see a URL looking something like this:
- Find the part beginning with &ll= until the next ampersand (&). (Don't confuse ll with sll!) That part should contain two numbers separated by a comma, shown highlighted here:
- The first of these numbers is your latitude in decimal notation; the second is your longitude. In this example, the latitude is 48.848663 and the longitude is 2.304533.
- To convert these numbers into degrees/minutes/seconds, the notation expected by Stellarium, head over to the FCC latitude/longitude converter
- In the second box on that page - labelled Decimal Degrees to Degrees Minutes Seconds - enter your latitude next to Enter Decimal Latitude and your longitude next to Enter Decimal Longitude. (Use copy-and-paste to avoid typos.)
- Press Convert To Degrees Minutes Seconds.
- Read out the latitude and longitude next to Result. For this example you would get 48° 50' 55.1868" and 2° 18' 16.3188".
- Next, convert +/- notation to N/S E/W notation.
- The result you got from the FCC uses plus/minus signs to show which hemisphere the location is on - actually it only uses the minus sign, if the result is positive then the plus sign won't be shown. Stellarium, however, requires directions (N/S for latitude, E/W for longitude) so you'll have to tweak the result a litle.
- If latitude starts with a minus sign, remove the minus sign and add S for South followed by a space in front of it. Otherwise, add N for North followed by a space.
- Likewise, if longitude starts with a minus sign, remove the minus sign and add W followed by a space in front of it. Otherwise, add E followed by a space.
- In this example, you would end up with N 48° 50' 55.1868" for latitude and E 2° 18' 16.3188" for longitude.
- You now have the latitude/longitude information in the format that Stellarium requires. You can double-check that you've made no mistakes so far by putting the final values back into Google Maps like this: N 48° 50' 55.1868" E 2° 18' 16.3188". The location shown should be pretty much the same location for which you copied the permanant URL in step 2. Compare to 8-10 rue Mario Nikis, 75738 Paris Cedex 15, France - and allow for a few meters of difference due to precision loss.
- Now for determining the altitude.
- Head over to topocoding.com.
- Pop in your latitude and longitude in the text fields labelled Latitude and Longitude. It doesn't matter which format you use, any seems to work - when in doubt, use the original decimal notation.
- Press the Add point button.
- A tool tip will pop up in the map display showing your altitude in both meters (m) and feet (ft). Copy-and-paste the altitude in meters somewhere.
- The latitude, longitude and altitude values you've got now can be copied-and-pasted into the text boxes in Stellarium's Location dialog. In this example, the final values are N 48° 50' 55.1868" and E 2° 18' 16.3188" with an altitude of 45 m. Because the Location dialog is somewhat idiosyncratic, I recommend to follow these steps:
- First off, ensure that for Planet you've selected Earth (duh!)
- Then choose your country from the drop-down list.
- Now enter the name of your location into the Name/City text field. It doesn't hurt if you put in the full location including street name etc.
- Ensure your computed latitude is in the clipboard (by copying it).
- Select all the text in the latitude text field and press Ctrl+V (Windows), Cmd+V (Apple) or the appropriate key for pasting your computed latitude. Then press Enter to ensure Stellarium registered the new value.
- Note that Stellarium is quite unforgiving when it comes to latitude/longitude. For example, if the latitude doesn't start with N or S, or doesn't end with a quote sign (") it won't be accepted properly and you won't get an error message if it's wrong. So be careful to copy the correct and full value.
- Follow the same procedure for the longitude text field.
- Fill in the altitude that topocoding.com gave you.
- Press the Add to list button. This will store your location permanently and also update the location display on the world map. Double-check that the red pointer shows the correct location.
- Finally, tick the Use as default checkbox and close the Location dialog.
- If something went wrong, select the new location in the Location dialog, press the Delete button, and start over. (The Delete function doesn't always seem to work, though.)
- Phew, you're done - enjoy your precisely calibrated Stellarium!