What is the best way to overlay a shapefile in Google Maps?
After some reading suggests that, converting shapefile into KML and overlaying KML in Google map is an option. If that is the case, how do I convert a shapefile into KMLs?
I believe there would be a few open source tools available for this conversion. Can anyone point to a tool to covert a shapefile to KML without any loss of data?
I like using (open source and gui friendly) Quantum GIS to convert the shapefile to kml.
Google Maps API supports only a subset of the KML standard. One limitation is file size.
To reduce your file size, you can Quantum GIS's "simplify geometries" function. This "smooths" polygons.
Then you can select your layer and do a "save as kml" on it.
If you need to process a bunch of files, the process can be batched with Quantum GIS's ogr2ogr command from osgeo4w shell.
Finally, I recommend zipping your kml (with your favorite compression program) for reduced file size and saving it as kmz.
as of 12.03.2019 FusionTables is no more...
Import the Shapefile into Google FusionTables ( http://www.google.com/fusiontables ) using http://www.shpescape.com/ and from there you can use the data in a number of ways, eg. display it using GoogleMaps.
I would not use KML. Instead, use GeoJSON which you can natively consume in Google Maps API now. It is a newer feature that didn't exist from the original responses.
In any case, simply open the SHP file in Quantum GIS, and then you can output it in any format you like (KML, GeoJSON).
If you are using Google Maps for Work, I found a premium extension that handles loading shapefiles directly where you can just connect direct to the shapefile that you generate from ESRI. I did a search on the CMaps site and found this snippet which loaded US by state shapefile: https://gmapsplugin.net/cmapsanalytics/assets/shapes/usstates.shp
var cMap = new centigon.locationIntelligence.MapView();
cMap.key([your_api_key]);
cMap.layerNames(["Basic Shapes"]);
cMap.dbfKeys([['Alabama','Alaska','Arizona','Arkansas','California','Colorado','Connecticut','Delaware','District of Columbia','Florida','Georgia','Hawaii','Idaho','Illinois','Indiana','Iowa','Kansas','Kentucky','Louisiana','Maine','Maryland','Massachusetts','Michigan','Minnesota','Mississippi','Missouri','Montana','Nebraska','Nevada','New Hampshire','New Jersey','New Mexico','New York','North Carolina','North Dakota','Ohio','Oklahoma','Oregon','Pennsylvania','Rhode Island','South Carolina','South Dakota','Tennessee','Texas','Utah','Vermont','Virginia','Washington','West Virginia','Wisconsin','Wyoming']]);
cMap.userShapeKeys([['Massachusetts','Minnesota','Montana','North Dakota','Hawaii','Idaho','Washington','Arizona','California','Colorado','Nevada','New Mexico','Oregon','Utah','Wyoming','Arkansas','Iowa','Kansas','Missouri','Nebraska','Oklahoma','South Dakota','Louisiana','Texas','Connecticut','New Hampshire','Rhode Island','Vermont','Alabama','Florida','Georgia','Mississippi','South Carolina','Illinois','Indiana','Kentucky','North Carolina','Ohio','Tennessee','Virginia','Wisconsin','West Virginia','Delaware','District of Columbia','Maryland','New Jersey','New York','Pennsylvania','Maine','Michigan','Alaska']]);
cMap.labels([['Massachusetts','Minnesota','Montana','North Dakota','Hawaii','Idaho','Washington','Arizona','California','Colorado','Nevada','New Mexico','Oregon','Utah','Wyoming','Arkansas','Iowa','Kansas','Missouri','Nebraska','Oklahoma','South Dakota','Louisiana','Texas','Connecticut','New Hampshire','Rhode Island','Vermont','Alabama','Florida','Georgia','Mississippi','South Carolina','Illinois','Indiana','Kentucky','North Carolina','Ohio','Tennessee','Virginia','Wisconsin','West Virginia','Delaware','District of Columbia','Maryland','New Jersey','New York','Pennsylvania','Maine','Michigan','Alaska']]);
cMap.polyDataSources([centigon.locationIntelligence.CMapAnalytics.DATA_PROVIDERS.SHAPE_DATAPROVIDER]);
cMap.layerTypes([centigon.mapping.Layer.TYPE.POLY]);
cMap.locations([["https://gmapsplugin.net/cmapsanalytics/assets/shapes/usstates.shp"]]);
cMap.panTo("USA");
cMap.zoomLevel(3);
Do you mean shapefile as in an Esri shapefile? Either way, you should be able to perform the conversion using ogr2ogr, which is available in the GDAL packages. You need the .shp file and ideally the corresponding .dbf file (which will provide contextual information).
Also, consider using a tool like MapShaper to reduce the complexity of your shapefiles before transforming them into KML; you'll reduce filesize substantially depending on how much detail you need.
Free "Export to KML" script for ArcGIS 9
Here is a list of available methods that someone found.
Also, it seems to me that the most efficient representation of a polygon layer is by using Google Maps API's polyline encoding, which significantly compresses lat-lng data. But getting into that format takes work: use ArcMap to export Shape as lat/lng coordinates, then convert into polylines using Google Maps API.
Just to update these answers, ESRI has included this tool, known as Layer to KML in ArcMap 10.X. Also, a Map to KML tool exists.
Simply import the desired layer (vector or raster) and choose the output location, resolution, etc. Very simple tool.
2018 already... I've found this fantastic online tool http://mapshaper.org/ to convert from ESRI shapefiles to SVG, TopoJSON, GeoJSON.
Here is the explanation of how to use it https://www.statsilk.com/maps/convert-esri-shapefile-map-geojson-format
Fast and straightforward! :)