I want to zoom & center a Google map enough to fit a whole block - google-maps

Given an address, is there a way to fetch a static Google map with certain parameters in order to show the entire block including the surrounding streets?
This is the result I'm trying to achieve (I just centered and zoomed manually from Google Maps to make the screenshot):
But when requesting via Static Maps API, using zoom 17 is too far:
and using zoom=18 is too close:
Not to mention that I can't figure out how to do the right centering of the map.


I don't think there's an out-of-the-box way of doing this. There are plenty of possibilities for which block you want to show.
Some complications (there are more, I bet) include:
if you're in a street corner, which of the 4 blocks should the sprite be panned to?
if the address is a park?
if your block has an irregular shape? (even with the rectangular-like blocks in NYC it is complex enough due to their rotation on North axis)
If you have the origin latitude and longitude instead of the address, you could try using the &visible=latLng2 argument for the Static Maps URL, where latLng2 is a modified version of origin including a delta (probably ~0.002 degrees) to make it look similar to your idea. This argument cannot be used with a given zoom.
Before:
After:
Maybe your best option is to go with some calculations in the middle (like Google Geo services to know which is the street around the corner, etc)

Related

Google maps search by address component

I have implemented a basic google places autocomplete in my web app, for example saying "Heraclion, Crete" and it translates it to the latlng coordinates that I want. I also used the mysql radius example from the api to show nearest entries. I also have locations in a second area of Crete, called "Rethymnon".
The problem now is the following. Supposedly one types just Crete. How can I get all the entries from Heraclion and Rethymnon? My code uses the radius approach as mentioned before. So I need something else to define it in a rectangular area.
Is this possible?

If the result contains a viewport (LatLngBounds), you could use that.
PlaceResult
geometry: The Place's geometry-related information. This includes:
location provides the latitude and longitude of the Place.
viewport defines the preferred viewport on the map when viewing this Place

Change DPI with Javascript Google Maps Api

I need to create a 80x80cm (or 33inchx33inch) map with Google Maps. This map will be printed and exhibited, so the higher DPI the better. Actually, in printing, a 300DPI is the minimum.
Now, I'm using the Javascript API in order to create the map I want :
- change the mapOptions with an array of styles with various colors
- add a Transit Overlay in order to have the map of the urban trains added over the map (see this aautar.digital-radiation.com/blog/?p=3761)
- add polygons as a link to KML URL to one of my maps
If you want to see the result : http://www.tellnet.fr/blog/test.html (it's very long to download since it's a 5000x5000 picture).
The problem is that, at the Scale level I want (with not too many details), the big picture I get is a 5000x5000, which gives a 150DPI only printable file.
To obtain a 10000x10000 picture as I would to print a 80x80cm map at 300 DPI, I need to :
- either my map zoom once, but then I've got soooo many details, that will be printed super tiny
- or change the DPI of the map, asking Google Maps to double it.
It would basically give me the same map at the same scale, but with thinner lines and texts (making a 10000x10000 pictures).
I know this is possible with the static maps Api, change the Scale value to 2 (see https://developers.google.com/maps/documentation/staticmaps/?hl=fr#scale_values).
The problem is that, this is the static maps API, so please can someone tell me if :
- it's either possible to do all the above things with the static API
- or change the "scale" value (ie the DPI value) with the Javascript API.
I also tried to change the meta viewport value, but this only works with mobile devices... (I searched for all solutions, now I'm blocked!)

How do you plot geo-encoded locations on a custom map?

I have a number of events in the US. I have addresses for these events, but it varies in accuracy. Some might be the full address, some might be just "Austin, Texas".
I'd like to plot these programatically on a map on a webpage with a marker as they'll change fairly regularly. The marker should be an internal link to the relevant row in the table of events lower down on the page.
The image doesn't need to be updated on the fly, just on the (say fortnightly occasions) when an event is added (e.g. a cached image is cleared and recreated)
Rather than use Google maps, I'd like to plot these on top of an image like this: http://0.tqn.com/d/geography/1/0/9/H/usa3.jpg
How would I go about putting markers on this image that correspond to the (rough) geolocation of these events?

Your best bet might be to use google maps and plot the locations and then just pull an image of the map - that way you can let google do all the work of placing the pins but not have to worry about people zooming, since it is a static image file.
Beyond that, you can type the locations into any mapping service to get a rough idea of the location and then place markers or dots on your map file in the same location. This would allow you to choose whatever image or color you want the icons/markers to be, since you will find and place them yourself.

Around-the-world path breaking in Google Static Maps

I'm creating Google Static Maps with a path between markers and have come across certain coordinate combinations that break the path.
The path breaks in this example (markers # Beijing, SF, NY, Azores, Rome):
http://maps.google.com/maps/api/staticmap?path=color:0xff0000cc|weight:3|39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577|41.89052,12.494249&markers=39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577|41.89052,12.494249&maptype=terrain&sensor=false&size=640x404
And works in this example (marker # Rome removed)
http://maps.google.com/maps/api/staticmap?path=color:0xff0000cc|weight:3|39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577&markers=39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577&maptype=terrain&sensor=false&size=640x404
The cause is not crossing over the Greenwich Meridian as I initially thought. It breaks even if I add a marker before that, seemingly any a point East of the automatically calculated centerpoint of the map...but only when the path starts on the other side of -180 longitude.
To prove that, you can see that the Beijing, SF, NY, Azores, Rome path displays correctly when I set the map centerpoint to -170,35
http://maps.google.com/maps/api/staticmap?path=color:0xff0000cc|weight:3|39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577|41.89052,12.494249&markers=39.904214,116.407413|37.77493,-122.419416|40.714353,-74.005973|38.721642,-27.220577|41.89052,12.494249&maptype=terrain&sensor=false&size=640x404&center=-170,35
Unfortunately, I can't programmatically set center like this because I never know the collection of points I'm going to get, and it would be next to impossible to detect that the passed points would cause a line break.
Any ideas?

First: you can calculate the center even if you don't know the collection of points (locations) at compile time: at runtime you know all the points (otherwise it would be not possible to insert the coordinates into the URL), therefore you can easily iterate over all the points and compute the center. You can computing the average of all coordinates and you get the geometric center (also called centroid): this is the easier way. Another way to do is to check the most distant pair of locations (for both, latitude and longitude) and then set the middle point as center: this requires slightly more coding (for instance to compute the longitude distance you need to take into account the you have to compute the distance in two directions, since it is possible to go 'around the world) and it has an higher complexity.
I don't go deeper in this topic because, even if you compute correctly the center of your points, this does NOT resolve the problem, and moreover the center provided automatically by the Google static map API is always correct: again the center is related to the problem, but it is not the (couse of the) problem.
An aspect that is trivial but important to keep in mind: Google static map draws a path between two locations always by considering the shortest path, i.e. by drawing the shortest straight line.
Therefore if you are in a situation where your path has to go from a location A to a location B, and the shortest path between A and B goes 'around the world' (or better, it goes out from one side of the image), then the path appears 'borken' as in maps that you have shown. In practice A and B are near the left and right margins of the map, and the map can not be centered in some point along the shortest path between A and B because of the others point of the path. And this is what happen when you remove 'Rome': without Rome the map can be centered in a way that the path is not borken.
Formally, I think that the problem appears (i.e. the path is broken), when the projection of the path on the equator is longer than 360 degree of longitudes, and the path always goes in the same direction (i.e. always west to east or always east to west).
Google static map in this situation simply adds another world map next to the first one: if you set the zoom to the minimum, you can see up to three world maps. This is really impractical for several reasons:
you can not zoom out infinitely;
if you want also insert markers into the map they will be drawn only on the 'main' map;
potentially you can have a path that goes around the world (passing in sequence from America, Europe, Asia, and America again and so on...) many times, and it would be really terrible to have so many little maps one after each other;
I googled a lot about this problem, and I didn't find any solution, there is a bug open on the bug tracker, but it is unsolved.
In my opinion the 'right' way to do is simply the following: at most one map and if a path has to goes out from one margin of the map/image, then it should appear on the opposite margin and continues to the destination, drawn on the same map.
So I found a first workaround:
you draw your path, and with the same style (line's color, etc) you also draw the path in a reversed way (Google static map allows to draws multiple paths in the same map), i.e. path=A|B|C&path=C|B|A and this will solve the problem in many situations (i.e. the path exits from one side of the image and enters from the other). Unfortunately this not works always: if you have a path that cross the image margin two consecutive times, then you lose a portion of your path
To solve this problem I found a second workaround:
- not draw simply the path and its reverse, but draw a different path for every pair of locations of the path (and reversed), i.e. for a path A->B->C then: path:A|B,path=B|C,path=C|B,path=B|A and this works always
The drawback is that in this way the URL becomes very long and the limit of 2048 characters for URLs is easily reached.
The best solution would be to compute manually the center, check manually where the path will cross the margin, and only for this portion of the path draw an additional path going between the two locations at the margin (and maybe also the reverse), but I do not think it really worth, although I do not think Google ever will solve this problem.

Google Maps default zoom level

I created a public map using my Google Map. I want to set a default zoom level, but it is not saved. Is this possible?
Also, is it possible to change the list of place markers?

the reference map that you supply (quebec summer festival) is called by the URL: http://maps.google.com/maps/ms?source=embed&hl=en&geocode=&ie=UTF8&msa=0&msid=112492115201367239282.0004609e0fcc239c4f792&ll=46.81084,-71.217113&spn=0.02056,0.038624&z=15
notice that the last parameter "&z=15" defines the zoom level (in the embed map code, "&z=15" becomes "& a m p ; z = 1 5" [remove spaces between letters]). if you change this you can increase or decrease the zoom level. if you suppress the zoom level, googlemaps will automatically calculate a zoom level when displaying said map. NORMALLY this leaves some of your map outside the frame.
so, just by supplying the URL with the desired zoomlevel you have solved your problem. this works very well with static maps. if you have a dynamically generated map (from a database, for example), the fastest solution is to put 2 markers (top left and bottom right corners) slightly outside your boundary box. this will force automatic zoom in the desired amount (hopefully).

Not using API just made a map points using my GMail account and made it public, like the following site:
http://maps.google.com/maps/ms?source=embed&hl=en&geocode=&ie=UTF8&msa=0&msid=112492115201367239282.0004609e0fcc239c4f792&ll=46.81084,-71.217113&spn=0.02056,0.038624&z=15

Nothing is saved by a web page. HTML browsing is stateless. If you want to save some information you will need to use similar trick as any other web applications. E.g. putting it in cookie and the setting the zoom level using the information in the cookie when you initial the page.