I have a working system with Google map API v2. I need migrate it on v3. I use some projections and point, which stored in own projection. So i need convert this points to latlong. How i can do this? Or i need set some options in the map and use needed projection?
for example I have point with coordinates x: 332525.708620, y: 389976.561487 in 27700 projection.
Use these functions...
fromPointToLatLng()
fromLatLngToPoint()
Related
I am trying to map a geojson file (A map of Alaska precincts, downloaded from the division of elections and then converted online to geojson) onto a choropleth map using folium, the problem is the coordinates are in 7-digit numbers like this:
[ -16624764.227, 8465801.1497 ]
I read on a similar post that this was most likely a US coordinate system like UTM or State Plane, and recommended using an API to reproject it. Is it also possible to access the coordinates directly such as with geopandas and divide them by 100000?
The data is most likely in a specific cartographic projection. You don't just want to divide by 100k - the data will likely have nonlinear transformations which have a different effect on the position depending on the location. See the GeoPandas docs on working with projections.
If the CRS of the data is correctly encoded, you can re-project the dataframe into lat/lons (e.g. WGS84, which has the EPSG Code 4326) using geopandas.GeoDataFrame.to_crs, e.g.:
df_latlon = df.to_crs("epsg:4326")
I'm building a web application using Angular and mapbox-gl-js as map library.
The map tiles are projected using EPSG:4326 Plate-Carrée and the dataset is GeoJson (WGS84).
Since mapbox supports only web mercator projection, the data is not displayed in the correct position on map.
Any suggestions how to reproject the dataset so mapbox is able to display the data in the correct location?
Thanks.
If I understand your question correctly, you have some raster tiles which are "projected" (well, not really) in EPSG:4326, and you would like to display them in Mapbox-GL-JS. You also have another dataset, in GeoJSON, also provided in EPSG:4326, which you would like to overlay.
As you note, Mapbox-GL-JS only supports the EPSG:3857 (Web Mercator) projection. It projects datasets (but not raster tiles) from EPSG:4326 to EPSG:3857 in order to display them.
Your good options are:
Find a different basemap in Web Mercator
Find a web service which can reproject the tiles you have on the fly
Maybe there's some way where you could let Mapbox-GL-JS think it's displaying your tiles in EPSG:3857, then somehow adjust the coordinates of your overlaid dataset so that when they're reprojected from EPSG:4326 to EPSG:3857 they end up in the right positions. But I can't think how to achieve that.
You could try asking at gis.stackexchange.com.
I use EPSG:3857 projection for View in Map. I can easily add OSM to my map.
When I use EPSG:3395 projection for View, I can easily add tile-layer with source in EPSG:3395(world mercator) projection.
But how to combaine on map tile-layers with different source projection(3857 and 3395) ? Is it possible in openlayers-3 ?
Thanx!
Not yet possible, should be possible around october when raster reprojection work has been finished.
https://github.com/openlayers/ol3/issues/3785
I would like to find out what projection is google map using is it EPSG:4326 or P900913 ? Also if you use the drawing tools what projection coordinates are generated?
EPSG3857 is the official designation.
Interactive web maps are using "Spherical Mercator" system which uses Mercator projection on
the sphere instead of WGS84 ellipsoid.
More information
Google Maps uses the Mercator projection for this purpose
https://developers.google.com/maps/documentation/javascript/maptypes#WorldCoordinates
while browsing into a certain bing map application, i need to extract the coordinates of a polygon.
in the html, all i get is a the relative location of the polygon, and i need the lat/lng coordinates.
You can use the PixelToLatLong() method to convert from pixel locations on the map to corresponding Lat/Long. See http://msdn.microsoft.com/en-us/library/bb429564.aspx for details.