I'm querying an SDO_GEOMETRY field to return a given point in a shape, and I would like to get the GPS coordinates for that point. My query is as follows:
select
sdo_lrs.locate_pt(sdo_lrs.convert_to_lrs_geom(shape),0.02).sdo_ordinates
from
TEST_SCHEMA.TEST_TABLE
where
route='ABC'
and
segmentnum='101.1'
This returns an SDO_ORDINATE_ARRAY like so:
MDSYS.SDO_ORDINATE_ARRAY(100000.203621556,999999.57084293,0.02)
How do I convert the first two elements of the SDO_ORDINATE_ARRAY into GPS coordinates? I haven't been able to find anything in the Oracle Spatial documentation related to a function that would accomplish this.
It turns out you have to transform the coordinate system of the shape before it's passed to convert_to_lrs_geom(), using sdo_cs.transform(). In this case the SRID is 8307 (thanks to jim mcnamara for pointing out that the SRID was the issue), so the SQL to return the correct coordinates is:
select
sdo_lrs.locate_pt(sdo_lrs.convert_to_lrs_geom(sdo_cs.transform(shape,8307)),0.02).sdo_ordinates
from
TEST_SCHEMA.TEST_TABLE
where
route='ABC'
and
segmentnum='101.1'
Related
Please can anyone explain the difference between
$table->geometry('positions'); and $table->geometryCollection('positions'); in laravel.
I'm assuming your database is MySQL. Please add it as a tag to your post then.
According to the manual:
https://dev.mysql.com/doc/refman/5.7/en/spatial-type-overview.html
Some spatial data types hold single geometry values:
GEOMETRY
GEOMETRY can store geometry values of any type. The other single-value types (POINT, LINESTRING, and POLYGON) restrict their values to a particular geometry type.
and
The other spatial data types hold collections of values:
GEOMETRYCOLLECTION
GEOMETRYCOLLECTION can store a collection of objects of any type. The other collection types (MULTIPOINT, MULTILINESTRING, and MULTIPOLYGON) restrict collection members to those having a particular geometry type.
The difference is that the last one can hold multiple entities (coordinates/points) in a single column. This is useful if you want to save a square shape for instance, which needs 4 points.
A practical example for the first one would be a location (which is a single set of coordinates (lat+lng)).
I sadly cant give you much information on how to use them within Laravel. However in raw SQL, it basically looks like this:
-- Add data to a GEOMETRY column
SET #g = 'POINT(1 1)';
INSERT INTO geo VALUES (ST_GeomFromText(#g));
-- Add data to a GEOMETRYCOLLECTION column
SET #g = 'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))';
INSERT INTO geocol VALUES (ST_GeomFromText(#g));
I have a column named wkt_geometry in a table in Postgres with data converted from latitude and longitude. But I want to convert the wkt_geometry to wkb_geometry using sql commands.
If I convert it directly from Lat and long it would even better.
Also I have seen the ST_AsBinary(geometry) but I dont understand the parameters involved.
WKT and WKT are two formats that represent Geometry (or Geography) type.
To convert between various formats, you need to construct Geometry type and then export it to desired format. In this case ST_AsBinary(ST_GeomFromText(wkt_text)) should generally work.
If you want to produce WKB directly from lat/lng - something like ST_AsBinary(ST_MakePoint(lng, lat)) should work too. Pay attention to argument order, SQL functions use lng / lat order.
I have a database which has latitudes and longitudes of various properties stored. I want to find out, which city does each of these properties belong to (all properties are in the US).
Talking about Postgresql, first of all you need to get a data of US cities boundaries shape file. Possible sites are
https://www.census.gov/geo/maps-data/data/tiger.html
https://www.census.gov/geo/maps-data/data/tiger-cart-boundary.html
https://catalog.data.gov/dataset?tags=cities
After that import data into postgres. I am assuming that your properties data is already stored in postgres. Make sure the SRID geometry type of cities boundaries is 4326. if not, you can convert it easily with ST_transform function.
Finally, to check which city some specific lat/long falls in, you need to convert the lat/long into point geometry and check against the cities data. e.g it would be some thing like this
SELECT c.city_name FROM cities_boundaries AS c, properties AS p
WHERE ST_CONTAINS(c.geom, ST_SetSRID(ST_MakePoint(p.longitude, p.latitude), 4326))
I am newbie to PostgreSQL and postGIS...I have a PostgreSQL database dump, which contains a series of location data.
The location data should be the longitude and altitude of some points but is stored in the sql file in a string of numbers and letters, which is odd for me. For instance:
0101000020E61000009513A7B4801F6340131CD8D0766A3BC0
How I can convert this string to longitude and altitude using the query of PostgreSQL?
If you have a postgis extension and than you can cast geography-location to geometry and use ST_AsLatLonText(geometry) function.
SELECT ST_AsLatLonText
FROM (0101000020E61000009513A7B4801F6340131CD8D0766A3BC0::geometry);
I'm trying to convert a shapefile I have to SQL format.
I've tried doing this using shp2pgsql, but, alas, this program doesn't read the SHAPEFILE.prj file, so I end up with coordinates in an inconvenient format.
Is there a way to convert shapefiles to SQL which respects their PRJ specification?
You may have things in one projection that you want to display or interact with in more familiar values, like longitude and latitude. For example Planet OpenStreetMap uses a spherical mercator and gives you values like this when you ask for text:
cal_osm=# select st_astext(way) from planet_osm_point limit 3;
st_astext
-------------------------------------------
POINT(-13852634.6464924 4928686.75004766)
POINT(-13850470.0501262 4930555.55031171)
POINT(-13850160.8268447 4930880.61375574)
(3 rows)
You can use st_transform to return a more familiar format like this:
cal_osm=# select st_astext(st_transform(way, 4326)) from planet_osm_point limit 3;
st_astext
-------------------------------------------
POINT(-124.440334282677 40.4304093953086)
POINT(-124.42088938268 40.4431868953078)
POINT(-124.418111582681 40.4454091953076)
(3 rows)
A prj file is essentially a text file that contains the coordinate system information in the ESRI Well-known-text(WKT) format. Could you just write a program that uses shp2pgsql to convert the geometries and then store the associated WKT string from the prj?
Of note: The WKT format is an EPSG accepted format for delimiting projected and geographic coordinate system information, but different authorities may have different names for projections or projection parameters. PostGIS might be different from Oracle which might in turn be different from ESRI. So if you store the prj's WKT make sure that it is in an esri_coordinate_system column. PostGIS might have a different naming convention format for parameters.
Also, in case you're interested, there is a C++ open FileGDB api that allows you to access row information without license. It's available in 32 and 64 bit on windows and linux:
http://resources.arcgis.com/content/geodatabases/10.0/file-gdb-api