Google Maps is a web mapping service application and technology provided by Google free (for non-commercial use),

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36
votes
3answers
11k views

What is the current Web Mercator projection code?

The web mercator projection, popularised by Google Maps, seems to be given a new EPSG code every couple of years. EPSG:900913 (Google in calculator text) was an unofficial code EPSG:3785 - is the ...
36
votes
4answers
5k views

Why has Web Mercator (auxiliary sphere) become the web map standard?

I understand what the difference is between the Web Mercator projection and Web Mercator Auxiliary Sphere (WMAS). I also understand that both Google and Esri have adopted this projection as their ...
34
votes
5answers
6k views

Why is the 'straight line' path across continent so curved?

This is the result of mapping the straight line path from a point in US to Poland using Distance Measurement Tool. Also, planes from Asia to US would travel almost over North Pole. Why is the path ...
23
votes
6answers
1k views

OpenStreetMap or Google Map Maker: where should I donate and volunteer my geographical knowledge?

I definitely know a lot about the places I visit and want to share it with everyone. I want to know if donating and volunteering at OpenStreetMap—which is where I have been helping—is a waste of time: ...
23
votes
2answers
10k views

EPSG 3857 or 4326 for GoogleMaps, OpenStreetMap and Leaflet

The discussion at What is the difference between WGS84 and EPSG4326? shows that 4326 is just the EPSG identifier of WGS84.. Wikipedia entries for Google Maps and OpenStreetMap shows that they both ...
22
votes
3answers
21k views

How to add Basemaps from Google or Bing in QGIS?

Like ArcGIS Desktop has the option of using basemaps from ArcGIS online, does QGIS have any such options?
19
votes
6answers
8k views

What's next if our KML is too big/complex for the Google Maps API?

Our web app includes simple mapping capabilities (currently just markers and KML overlays on an embedded Google Map). This works pretty well; the only real limitation we face is KML overlays that go ...
18
votes
6answers
49k views

Display a local file in Google Maps

How can I get a KML/KMZ file to display on Google Maps without a public facing web server?
16
votes
8answers
40k views

How to avoid Google map geocode limit?

I'm creating a custom google map that has 125 markers plotted via a cms. When loading the map I get this message: Geocode was not successful for the following reason: OVER_QUERY_LIMIT I'm pretty ...
16
votes
6answers
8k views

Map projection in OpenLayers

I want to overlay some data whose projection is WGS-84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows: map = new OpenLayers.Map('map', { ...
14
votes
2answers
2k views

Is it possible to gray out a Google Maps map except for some area?

What i am looking for is a way to emphasize a certain area on a Google Maps map by graying out the rest of the world. I heard about some solution of using 2 polygons of which 1 is visible and the ...
14
votes
3answers
439 views

How are Google serving up their Styled Maps?

As we all know, Google changed web mapping when they introduced Google Maps. At the time of writing this, tiled maps are now the norm with web mapping. For example, with ArcGIS Server, you cache ...
14
votes
3answers
1k views

What is the wire format for Google's new vector map tiles?

Google recently released new vector cartography for their mobile maps. I'm curious if anyone here has any insight into the wire format they use for transmission? I've experimented with a few formats ...
13
votes
2answers
1k views

How can I fix my complex Polygons so they show correctly in Google Maps?

Problem: I'm trying to find a way to fix some broken polygon shapes and I'm not sure how I can do this. Details: I've got a number of polygons which I basically imported from TIGERLINES a while ...
12
votes
5answers
900 views

Quality of free geodata compared to commercial sources

What are the sources of excellent geo-location data as possessed by Google Maps ? I am wondering that, even with large amount of volunteer work involved, why is OSM data not comparable to theirs in ...
12
votes
2answers
1k views

Technical and usability differences between OpenLayers and Google Maps API V3

I know this is supposed to be a wiki question, but the feature has been taken of the site What are the main differences between OpenLayers and Google Maps api? What are the strengths and weaknesses ...
12
votes
2answers
6k views

Google markers at same address not showing all markers

I've been working on this map - http://www.mediwales.com/mapping/test/ It's plotting companies fine and clustering them ok but a problem has arisen with companies in the same building with the same ...
11
votes
8answers
4k views

What methods are there to produce map tiles for google maps?

newbie to stack exchange here. I'm currently using the automatic tile cutter found here to make the standard 256x256 tiles required to make a custom map type for my map. The map tile cutter script ...
11
votes
2answers
5k views

What is the difference between EPSG:900913 and EPSG:3857?

I'm using the QGIS google layers plugin to digitize a parcel as a shapefile. Later I want to import it to PostGIS. I know that google maps use a special 'google mercator' projection. What is the ...
11
votes
4answers
1k views

Geocoding API Comparison

Is there a good updated source for comparing existing Geocoding APIs (i.e. Google, Mapquest) and their features? I'm really interested in their language support as well. For example, Google has ...
11
votes
3answers
3k views

Open source alternatives to Google's StreetView engine?

I am looking to create an open source javascript app using either Leaflet or OpenLayers. Is there any way to implement panoramic views (similar to Google's StreetView) into either of these, or any ...
10
votes
6answers
946 views

What is this “brown spot” in Google maps?

I was in Google maps today and noticed near Baltimore, US where the river is, there's a huge brown spot. Is this due to all of the waste? If so, will this keep going all the way into the ocean?
10
votes
9answers
6k views

Algorithm for finding irrregular polygon centroid (label point)

I need to find a centroid (or label point) for irregularly shaped polygons in Google Maps. I'm showing InfoWindows for parcels and need a place to anchor the the InfoWindow that is guaranteed to be on ...
10
votes
4answers
617 views

Suggestions for simple mapping platform for alumni web site

I'm working on a proof of concept alumni site with a WordPress backend. I want to have a very simple map that shows where alumni are living. I'm thinking something like the Bing API or a simple open ...
10
votes
2answers
820 views

Drawing Day and Night on a Google Map

I'm looking to plot day/night on a Google map, for an arbitrary point in time. I'm familiar with generating map tiles; I'm just looking for an algorithm to tell me whether a particular point on the ...
10
votes
1answer
812 views

Can you query overlapping user-defined polygons at a given point in Google Maps?

I need to find out the limitation of working with the Google Maps API, and the possible solutions for doing semi-complex spatial comparisons. What I'm looking to achieve is a system of comparison ...
9
votes
4answers
1k views

What is a “mashup”?

GIS users mix spatial data layers from an early age of GI science. What is new in the concept of "mashup"? Is it something really new, or only a trendy word?
9
votes
1answer
7k views

How to apply custom Google map style in OpenLayers?

Recently I stumbled upon interesting article showing potential of adding custom styles to Google Maps. Some examples of styled maps can be seen here and you can design your own from scratch here. ...
9
votes
9answers
12k views

Is it possible to expose Google Maps as background map through ArcGIS server?

I am doing a (non commercial) project where the client doesn't have the budget for purchasing map data like that provided by TeleAtlas. They only need map data for a background map, and they'd like to ...
9
votes
1answer
102 views

Google Maps/Earth becoming GIS solutions yet? [closed]

I've been researching internet lately to make a comparaison between Google Geo solutions ( Google Maps, Google Earth) and other GIS solutions (Free of charge or commercial, QGIS, ArcGIS, etc.). I can ...
9
votes
2answers
301 views

Can I sell maps to third parties if I have Google Earth Pro License?

Not sure if this question is suitable for SE but I can't find answers anywhere else. I work as a GIS Analyst for a mining company that has its own GEPro license. As part of my job, I make PDF maps, ...
8
votes
4answers
844 views

Satellite Imagery Providers

I'm building a web application - my requirements are: Must have global satellite imagery. Must have easy to use API's that are capable of geoJSON data imports, mouse and keyboard gestures, etc. To ...
8
votes
5answers
3k views

How to emulate this grayscale basemap look+feel in Google Maps

I love the design on the Development Seed homepage, where they've used a grayscale basemap with bold 3D-style graphic markers. It appears that they've used the ModestMaps API to create a tiled ...
8
votes
3answers
893 views

What GPS device do I need for vehicle tracking?

I am a programmer with no connection to Geographic information, except that I work on application which uses google maps. So here is my problem. I need some device, which I will be able to set in a ...
8
votes
3answers
1k views

How to obfuscate data when using Google Maps?

I've been working on a google map (v3 of the api) that is plotting 120 markers or so (or will do shortly) - see http://www.mediwales.com/mapping. If you view the source the map data is for all the ...
8
votes
4answers
432 views

Geolocation database of beaches

Anyone know where or how to obtain a database of worldwide beaches? Required fields are: name latitude longitude coastline aspect (if possible) Alternatively, is there a way to query Google Maps ...
8
votes
4answers
1k views

Performance of google map tile creation processes

I know that question is rather vague but please bear w/me. I'm trying to get an idea of what sort of product performance - specifically timing - people have seen for various methodologies they have ...
8
votes
4answers
1k views

How to Geocode a City

First, a little disclaimer. I know that I can just call one of any number of geocoding APIs to perform this for me. This is more of a curiosity than anything else. With that aside, how does someone ...
8
votes
1answer
659 views

Generating Heatmap from PostGIS

I have GIS data in a PostGIS data base and would like to generate a density map and display them on a Leaflet/Google Maps. Question: What is the recommended/typical method for doing so, without ...
8
votes
4answers
4k views

Geocode address once in google maps, save in database, read geocoded result from there on

Is it possible to geocode an address, save the result in a database, then read that result from there on? I'm using a Google map that is geocoding hundreds of addresses which obviously hit the ...
8
votes
1answer
4k views

Using Drop Markers and MarkerClusterer together?

I want to create a rather visually appealing representation of time-series data (Costco Store Locations w/ opening dates). My idea was to plot them on a map, in time-series, but it seems that the ...
8
votes
3answers
4k views

OpenLayers With StreetView Overlay

Im trying to add StreetView functionality to my OpenLayers web app, and would like to add the overlay showing StreetView availability to the map itself. I have seen an example of it being done ...
8
votes
2answers
3k views

How to cluster Google Maps kml overlay

I have several thousand markers stored in a kmz file that I load into a Google Maps (v3 API). I've looked around to find a way to cluster the overlay data, but to no avail. MarkerClusterer looks ...
8
votes
2answers
984 views

Nearest point on a line ( Spherical / Mercator projection )

I have a line (Ax,Ay - Bx,By) over a mercator projection (google maps) and a random point (Cx,Cy) nearest to that line, i would to know the closest point (transparent blue on the image) over that line ...
8
votes
2answers
207 views

Google Maps and Search for KML URL

Can anyone tell me how I could add the functionality as seen on google maps that allow users to specify a URL to a KML file in the search bar? I would like to include this in my own embedded map but ...
8
votes
2answers
874 views

Why does one part of GML -> KML conversion not work on Google Maps?

Brand new to all of this, not even sure this is the right forum to ask in... I have a client who wants to visualise cancer incidence and mortality rates by local/unitary authority across Great ...
7
votes
4answers
5k views

Plotting KML files onto a Google Map

I would like to show a map on my website. I have 2 different kinds of KML files that need to be plotted. One defines region boundaries. The other points within those boundaries. The region boundaries ...
7
votes
5answers
862 views

Buffers of public transportation transit times

I'd like to be able to create buffers/zones/rings of transit times using Denver's public transportation system. For an example of what I'm talking about, check out triptropnyc.com - I don't need it ...
7
votes
1answer
142 views

Using Google Maps to track work per building and allowing users to manipulate that data

I work part time for a political campaign office, who are going door-to-door for several months at a time, all over a city. We need a system to track where we have been, and how long ago we were last ...
7
votes
3answers
8k views

How can I plot GPS coordinates on Google Map

What is the best way to plot GPS coordinates on a Google Map? Are there any tools that can do that (written in python specifically)?