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Questions tagged [geography-data-type]

geography data type, stores ellipsoidal (round-earth) data, such as GPS latitude and longitude coordinates.

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What is geometry(4326), and can you do Cartesian calculations with unprojected ellipsoidal coordinates?

I know Geography(4326) is an unbounded, and unprojected, and covers the entire world with ellipsoidal coordinates. I get that the math on this system is done on a spheroid. I also get that with a ...
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25 views

How to set the extent of a PostGIS geography table?

I have multiple geography tables in PostGIS database. All of them have extents of (-180,-90;180,90), probably in their metadata, which makes editing difficult. I'd like to set the extent to exactly ...
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1answer
35 views

Converting geography types in PostGIS? [duplicate]

I have multiple tables in different geography types. For example, some are Point, some are PointZM, some are MultiPoint, etc. I need to convert all of them to PointZ. I have searched the documentation ...
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0answers
140 views

Pulling Spatial Data in Geography Format From MS SQL Server 2008 Using ogr2ogr

Can the MSSQLSpatial driver support geography fields queried from MS SQL Server 2008 as spatial data? Background I have been using unixODBC on an Ubuntu 16.04 machine with ODBC Driver 17 for SQL ...
3
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1answer
193 views

SQL WKT draws well with geometry, but not with geography data type

I have a following piece of code DECLARE @g geometry; DECLARE @borders geography; SET @g = geometry::STGeomFromText('SOME WKT', 0); SET @borders = GEOGRAPHY::STGeomFromText(@g.MakeValid()....
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225 views

SQL Server - ESPG:4326 data stored in Geometry column

It seems that the Microsoft SQL Server Geography data type is better suited for lat/lon because Geography "stores ellipsoidal (round-earth) data, such as GPS latitude and longitude coordinates." ...
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0answers
412 views

How to Cast geometry to Geography in SQL script in MS SQL Server?

I have a Table with some spatial Data in MS SQL Server. The datatype of the spatial column is geometry. I'm trying to get the closest data from an input file using the following query: DECLARE @g ...
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0answers
169 views

SQL Geometry type and Geography type conversions/projections

I am working with a replica database managed in Sql Server Management Studio 2016. My geographic data of points, lines, and polygons are projected in WGS_1984_UTM_Zone_17N Meter and SRID of 32617. Its ...
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1answer
41 views

Saving borough boundaries as MultiLineStrings or MultiPolygons?

I am creating a database in PostGIS and I have a column that will save the boundaries of boroughs. The app will later query the database, asking what points, lines or polygons are inside those ...
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2answers
325 views

Is PostGIS geography type EPSG:4326 only?

I was under the impression that the geography type only uses the lat,long based coordinates EPSG:4326. And I didn't remember having to specify a CRS for a geography column. However, from this ...
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2answers
74 views

Does transforming postGIS geographic data to EPSG:4326 , makes them geographic?

I am reading this about "Clustering on Indices" and in 25.2 says that The geohash algorithm only works on data in geographic (longitude/latitude) coordinates, so we need to transform the ...
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1answer
458 views

Add Geography Column to an existing table

I Have an existing table GPSPosition which has a coma seperated LatLong column. I have attempted to add a geography column using the query: alter table GPSPositions add geographyColumn as geography:...
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120 views

Chainage of line (Geographic Coordinates) in meter without reprojection (true length on spheriod)

How is it possible to get kilometer points (every 0.5 km) on a curvy line (geographic coordinates), that runs for 90 km from south to north. I want the true distance (Earth's curvature included). If I ...
2
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1answer
117 views

Fast(est) way to detect if point is in range of another point? (Geographic Coordinates)

I'm looking for a way to detect if 2 points are "near enough" each other for a match, and hopefully, if the range could be specified in metric system (each item may have different ranges, but there ...
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2answers
714 views

Transforming geographical points to geometry in PostGIS?

I have a PointField(geography=True) field in Django, which is translated into the following Postgres type: geography(Point,4326). I set the geography field to True because I thought it made sense for ...
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1answer
678 views

Export geography field from SQL for use in GIS

I currently have a table in SQL server management studio (2012) with a geography column. It definitely has valid spatial data, as I can view it in SSMS: What I want is to export the data as a ...
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2answers
1k views

Get latitude and longitude of a geography column

When doing the query in postgres to one that has a column whose data type is geography(MultiLineString, 4326) throws me the following result: select geom from base.osm_roads_free_1 limit 100; "...
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1answer
101 views

Strange result with ST_Distance, geography type and equator

I am getting strange results with distance queries in PostGIS using geography types and ST_Distance. According to the docs, ST_Distance should return the distance in metres between two geography ...
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1answer
254 views

What is ST_Geometry, ST_Curve and ST_Surface on PostGIS?

I dont't have any experience with geographics databases so I hope that you be patiente with me, so I opened this question (PostGis and datatypes WKT) in the past week about the datatypes in the ...
3
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1answer
154 views

Adding association for location with city or zip code when using PostGIS to add markers using geography?

On my front end, I am using google maps JS api. I am adding markers, the google maps event gives me the lat/lng for where I add the marker. I'm adding that marker into my postgres database: INSERT ...
43
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3answers
8k views

What is the purpose of PostGIS on PostgreSQL?

PostgreSQL already supports spatial data types, operators and indexing. What does PostGIS provide exactly that made it necessary to exist as an extension to PostgreSQL? Why don't we all just use ...
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0answers
436 views

How to implement Geography or geometry with spatial index implementation to find entities in the bounding box?

I have entities saved in SQL table with Lat and long values. I added another column to store Geometry values. Code for updating Geometry column UPDATE [dbo].[table] SET [GeoLocation] = geography::...
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2answers
5k views

Inserting lat/long data into geography column of SQL Server 2012?

is it possible to insert lat/long data into geography column just by typing the coordinates lat/long as a double or string: INSERT INTO LOT_EXPLOITATION_LOT VALUES (3621,'oui','Forêt Boréale',560000,'...
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1answer
103 views

How to set my ESPG to geography POINT in PostGIS?

I'm trying to create a table into my PostGIS 2.3 CREATE TABLE destinations ( id serial PRIMARY KEY, sector integer REFERENCES sectors(id)...
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1answer
61 views

Why I obtain different values calculating distance between two point in the space using this “Great-circle distance” formula and Google Earth tool?

I am not so into database and GIS and I have the following doubt about this function used on a MySql database to calculate the distance between 2 points. I am started from this tutorial where there ...
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1answer
168 views

Choosing target CRS value when doing geographic calculation?

In postgis, I use geography type, it support many geographic calculation, like st_dwithin(geography1, geography2, distance). What I need to do is just giving some points coordinates (lng, lat pair), ...
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0answers
125 views

Finding points around closest point of linestring ordered by distance using PostGIS?

I am looking for a way to improve my solution of the following problem in PostgreSQL (using PostGIS). Given a point A, a Linestring B and a series of (yellow) points spread all over the area in which ...
2
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2answers
386 views

How to pass parameters to PostGIS queries containing geography type in Python using psycopg2

I have the following example (adapted from the PostGIS manual (version 2.2): CREATE TABLE global_points ( id SERIAL PRIMARY KEY, name VARCHAR(64), location GEOGRAPHY(POINT,4326) ); ...
2
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1answer
528 views

Geography for Sql Server STIsValid() getting error

I am getting the following error Could not find method 'STIsValid' for 'Microsoft.SqlServer.Types.SqlGeography' in assembly 'Microsoft.SqlServer.Types' on the following query. select ogr_geog from ...
3
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2answers
2k views

ERROR: Only lon/lat coordinate systems are supported in geography

I'm trying to find out all the circles stored in the database(The circles are present all over the world) that intersect or overlap a given circle. I've stored the circles like this: CREATE TABLE ...
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1answer
58 views

Get value from list class (vector) in R [closed]

I have a simple question about corce(?) list class data into vector. I extract a tif file from polygon to achieve a list. Maybe the class of list is leaded by extract function. I check the list length ...
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0answers
234 views

How to properly deal with rectangles being curved on geographies?

I'm using Microsoft SQL Server to store simple data for administrative boundaries of the world (lots of polygons). I store this in a geography data type column. Afterwards I query these polygons by a ...
2
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1answer
474 views

How can I convert PostGIS geography to geometry and split polygons that cross the antimeridian

I have a PostGIS 2.2 table that stores polygons as geography type. The table contains several polygons that cross the antimeridian. I would like to split these polygons at the antimeridian and ...
6
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1answer
230 views

Preventing invalid values in PostGIS geography

If I use pgAdmin to insert a point with an invalid latitude, say 91°, I receive the following notice before the query completes successfully: NOTICE: Coordinate values were coerced into range [-...
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3answers
1k views

Why is geography faster than geometry for distance calculations?

Intuitively, I thought geometry would be faster than geography distance calculations, but this says otherwise: https://stackoverflow.com/questions/3547699/need-performance-on-postgis-with-geodjango#...
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1answer
168 views

Bounding rectangle of a geography

How to get a bounding box (in the form of a Polygon, or anything else where it's easy to extract the corner coordinates from) of a given Geography item? Something that would look like: SELECT ...
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1answer
261 views

Cleaning up inexact polygon unions

I have geography data stored in SQL Server and I am trying to merge polygons from two data sets together. The problem is that they do not line up exactly, so unioning them results in narrow gaps ...
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0answers
59 views

What is the file format

I have been sent a text-file (see below) with '.txt' extension. I would like to process it in ArcGIS or any other GIS-tool. Unfortunately I do not know how to automatically load the file as ArcGIS ...
2
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1answer
109 views

Bounding box along parallels and meridians

I have a PostGIS table with a column location geography(Point,4326). To select data from a specific region I use location && ST_MakeEnvelope(65,-77,120,-75). This may work well for most ...
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1answer
880 views

Postgis How to populate column with geography data from geometric data?

I stored my point date in geometry format with SRID 4326 supposed EWKB (data looks like this "0101000020E610000071F1A611E9392640AECD10D8E68C4A40") = way geometry(Point,4326) I want to have the ...
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0answers
296 views

Difference between adding spatial layer from MSSQL through “browser” and “add MSSQL table”

So I am trying to pinpoint the difference of adding layers from MSSQL Database that contains spatial layers like geography and geometry. I have noticed that when adding from the browser it retains it ...
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1answer
1k views

SQL Server geometry vs. geography in Esri map service

We have a SQL Server 2008R2 database where point coordinates are stored as decimal degrees. I want to create an Esri map service which shows those points. As the point data is dynamic I decided to ...
3
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1answer
633 views

SQL Server Geography Query works but Geometry Query Does Not - Different Tables, Similar Schemas

I am trying to get a Geometry query to work. A similar Geography query works fine but I must work with a table that uses a Geometry type. Although the Geography version returns lots of records as ...
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1answer
588 views

Changing ArcSDE binary formatted data to MSSQL Geography or Geometry data types? [closed]

We are currently using ArcSDE 9.3 to store our Geodata. In a project which is currently being implemented, the software being used can access most data formats including the ArcSDE binary format and/...
2
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2answers
875 views

SQL Error: Latitude values must be between -90 and 90 degrees

I'm more of an ArcGIS user than a SQL Server user but I have polygon data in a 'geography' type in SQL 2008 R2. For a couple of these poly layers, I get this persistent drawing error in ArcMap: ...
32
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1answer
29k views

Choosing SRID and what is its meaning? [closed]

I'm new to GIS, in PostGIS, and I'm struggling with the SRID concept. How do you choose a SRID for a database column? This is making me crazy. Why do I need to choose a SRID? What's its meaning? ...
14
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3answers
6k views

Using geometry rather than geography data types in SQL Server Spatial?

Historically I've mainly worked with simple latitude and longitude coordinates in a SQL Server. I stored them as a geography datatype in SQL Server, and rendered them on a variety of displays (...
2
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1answer
2k views

POSTGIS: function st_collect(geography) does not exist

I am trying to use some Geography functions, but I am getting an error that (all) functions are not existing. I have checked other Stackexchange posts (e.g. this one), but the solutions did not work ...
6
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1answer
2k views

Is it possible that a good spatial index just cannot be made?

I have about 6 million rows with geography spatial features - they are all 1000 meter radius hexagons all over the US. There are a couple hundred thousand that would have been NULL, which I updated ...
16
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3answers
23k views

Performing bounding box query in PostGIS? [closed]

I have a Postgres table, with almost 2 million rows, with a long-lat coordinates field in the form POINT(-73.4938 33.2405). Supposing there's a geospatial index on that field, what's the most ...