How to get Lat and Lon coordinates from PostGIS?

How to get Lat and Lon coordinates from PostGIS?

I have a PostGIS table with a geometry field of SRID 3857 data. I want to get the centroid of the geometry as lat/lon coordinates, but can’t seem to convert the values correctly:

How to add a Geom to a table in PostGIS?

Newer versions of PostGIS allow the following, slightly more common, syntax: ALTER TABLE your_table ADD COLUMN geom geometry (Point, 4326); Then use ST_SetSrid and ST_MakePoint to populate the column: UPDATE your_table SET geom = ST_SetSRID (ST_MakePoint (longitude, latitude), 4326);

How to create geometry from lat / lon in table?

Creating geometry from lat/lon in table using PostGIS? I have a table with over 800,000 records including a lat and long column. The data source did not create geometries, so I was looking around how to do this.

How to get decimal values from geometry in PostGIS?

How would I get decimal values, which is a human-readable coordination? In addition to ST_AsText (which returns geometry as WKT / Well Known Text), there are several additional output formats, like ST_AsGeoJSON (). Take a look in http://postgis.net/docs/manual-2.0/reference.html#Geometry_Outputs and choose, what fits your needs best.

When to use sfgcal based St _ intersection-PostGIS?

If working with 3D geometries, you may want to use SFGCAL based ST_3DIntersectionwhich does a proper 3D intersection for 3D geometries. Although this function works with Z-coordinate, it does an averaging of Z-Coordinate values when postgis.backend=geos. postgis.backend=sfcgal, it will return a 2D geometry regardless ignoring the Z-Coordinate.

Which is the geodetic geometry type in PostGIS?

The geography type provides native support for spatial features represented on “geographic” coordinates (sometimes called “geodetic” coordinates, or “lat/lon”, or “lon/lat”). Geographic coordinates are spherical coordinates expressed in angular units (degrees). The basis for the PostGIS geometry type is a plane.

How to get geometry from multiple tables in PostGIS?

Take a look in http://postgis.net/docs/manual-2.0/reference.html#Geometry_Outputs and choose, what fits your needs best. Source: Getting geometry from multiple tables using PostGIS?

How to load raster data in PostGIS in Linux?

The syntax is simple. In a terminal type gdalinfo followed by the name of the file. ( For newcomers to Linux you open a terminal in Ubuntu 12.04 by pressing control + alt + T. Then you can move to the folder where the data is using cd to avoid having to type the full path.)

How to correct no data layer in PostGIS?

An easy way to correct the layer as sent is simply to use gdal_translate to produce a new layer with the correct no data value. This can be done directly on the command line, or in the GUI by choosing the relevant option in Quantum GIS from the raster menu.

Can a Linux user change the PostGIS data base?

If you have just installed your first PostGIS data base and still are not sure how it all works then it is almost inevitable that your Linux username has not been registered in the list of database users. You still do not have any permission to use or change the data base until you register your name as a super user.

How to convert coordinates to latitude and longitude?

I need the latitude and longitude, in EPSG: 4326, of each point. Could someone give me a valid example of how to use ST_Transform (). ST_Transform — Returns a new geometry with its coordinates transformed to the SRID referenced by the integer parameter.

What do St _ X and St _ Y do in PostGIS?

ST_AsText returns the well-known text. ST_X and ST_Y return the actual longitude and latitude (assuming geom is in the appropriate SRS). These st_x/st_y functions are confusing.

Which is the best GDAL for installing PostGIS?

GDAL, version 2+ is required 3+ is preferred. This is required for raster support. http://trac.osgeo.org/gdal/wiki/DownloadSource . If compiling with PostgreSQL+JIT, LLVM version >=6 is required https://trac.osgeo.org/postgis/ticket/4125 . GDAL (pseudo optional) only if you don’t want raster you can leave it out.

How to install PostGIS in a spatial database?

Once PostGIS is installed, it needs to be enabled ( Section 3.3, “Creating spatial databases” ) or upgraded ( Section 3.4, “Upgrading spatial databases” ) in each individual database you want to use it in. 2.2. Compiling and Install from Source 2.2.1. Getting the Source 2.2.2. Install Requirements 2.2.3. Build configuration 2.2.4. Building 2.2.5.

Do you need to enable PostGIS in PostgreSQL?

Once postgis is installed, it needs to be enabled in each individual database you want to use it in. The raster support is currently optional, but installed by default. For enabling using the PostgreSQL 9.1+ extensions model raster is required. Using the extension enable process is preferred and more user-friendly.

Can a point be projected to a geodetic coordinate system?

If the point coordinates are not in a geodetic coordinate system (such as WGS84), then they must be reprojected before casting to a geography. In this example a point in Pennsylvania State Plane feet (SRID 2273) is projected to WGS84 (SRID 4326).

How to calculate the distance between two points in PostGIS?

Your second set of points are 62.74 meters away from each other, based on the same query. Note there is also ST_Distance_Spheroid which takes a third parameter, the measurement spheroid, ie, an approximation of the earth’s shape.

What is the coordinate reference system in Google Maps?

Your coordinate reference system (CRS) is 4326, lat/lon. This is a common source of confusion with Google Maps: 3857 is the CRS used by Google Maps for its tiles, and is projected meters based on a spherical globe.