Questions tagged [coordinates]

Any of a set of two or more numbers used to determine the position of a point, line, curve, or plane in a space of a given dimension with respect to a system of lines or other fixed references.

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70
votes
4answers
140k views

Getting coordinates from geometry in PostGIS?

This line: SELECT geom FROM myLayer.geom will return a hex value. How would I get decimal values, which is a human-readable coordination?
62
votes
12answers
142k views

Creating point features with exact coordinates in QGIS?

How do I create point features with exact (manually entered) coordinates in QGIS? I get precise GPS coordinates from a survey team which I need to add to a point layer. What I want: -Add point, type ...
40
votes
1answer
17k views

Is WGS84 itself a Coordinate Reference System?

I was wondering the difference between WGS84 and EPSG:4326 (see this). Can then WGS84 on its own be defined as a Coordinate Reference System? Or is it just a datum so that a Coordinate System must ...
32
votes
9answers
73k views

Generating random locations nearby?

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. This is the formula i came up ...
31
votes
2answers
3k views

Why do we use the terms “longitude” and “latitude” for a spherical body?

To specify a geographic coordinate we use the terms “longitude” and “latitude”. Far as I know, these terms derive from the Latin latitudo (= breadth) and longitudo (= length). In German we use the ...
22
votes
6answers
26k views

Moving vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it using QGIS?
21
votes
4answers
35k views

List of central coordinates (centroid) for all countries?

I need a list of the central points (centroid) for all countries: China: lat/long (coordinates of the most central point in China) France: lat/long (coordinates of the most central point in France) ...
17
votes
3answers
48k views

Change OpenLayers 3 view center

I'm using OpenLayers 3 to interact with some maps. I first declare my map: map = new ol.Map({ target: 'map', layers: [ new ol.layer.Tile({ ...
17
votes
2answers
13k views

Leaflet: Container coordinates vs Layer coordinates?

What is the difference between map container coordinates and layer coordinates? From what I gathered, the map container coordinates are always relative to the map viewport, and while layer ...
16
votes
1answer
1k views

What format is a location represented like this?

While converting an old system, I came across a position column with values in a format like this: 38RQT6410550656 While I've never seen global positioning represented this way, putting this in ...
16
votes
2answers
20k views

Converting between wgs84 and nad83

This is a newbie question that is about converting between wgs84 and nad83. I have aerial photos that I am trying to compute lat long coordinates for as closely as possible. There are several factors ...
14
votes
3answers
13k views

Given a set of coordinates, how can I calculate the minimum bounds?

I have a set of coordinates in lon/lat. There are always at least 3 ordered coordinates that form a poly (if they were projected flat). How can I calculate the minimum bounds for these coordinates as ...
12
votes
2answers
24k views

Using Leaflet Js, is it possible to know the onclick location of a Marker (ignore anchor point)?

I have a marker object that is of a specific height and width, and although it is pointing a single coordinate, the visual representation of the marker spans many pixels. When I click on the visual ...
11
votes
5answers
15k views

Calculating coordinates of square x miles from center point?

I am trying to create a x mile square (or circle) around a central point, where all sides of the square would be x miles from the centre. I need the 4 corner coordinates. It is scrambling my brain ...
11
votes
1answer
32k views

Making POINT from longitude/latitude coordinates in existing table using PostGIS?

I would like to make a POINT using the longitude and latitude columns of an existing table. Here's a link to the documentation of ST_MakePoint. Here's my table: CREATE TABLE sysinst.bio ( oid ...
10
votes
1answer
21k views

Manually editing point coordinates in QGIS?

Is there a tool for shapefiles or a QGIS plugin available, which will enable me to edit the coords of a point manually ? ("tool" -f1 "Tsunami Gauge"-move x1.abcdef -to x2.ghijkl) I do have ...
10
votes
2answers
1k views

How to create dynamic leader lines?

I'm trying to create dynamic leader lines by using a PostGIS view in addition to the QGIS „Move Label“ tool. CREATE VIEW leader_line AS SELECT gid, ST_MakeLine(geom, ST_SetSRID(ST_MakePoint(...
10
votes
2answers
5k views

How do I group near points with GPS positions?

I'm an IT person so I don't know too much about projections and so on, I hope you can help me. I have made an application for Android that collects a GPS position, so I have the latitude and the ...
10
votes
1answer
387 views

Georeferencing Museum specimens with poor locality descriptions

I am currently collating a list of specimens from databases of various natural history museums for further research. However, a well known issue associated with majority of historical data is the lack ...
10
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0answers
39k views

How to add Lat/long columns to a point layer which is not in WGS84? [duplicate]

I need to extract the Lat/long coordinates of the centroids of districts. My QGIS project SCR and the different layers have all been set on "WGS 84 / UTM zone 18N". I've created the centroids using ...
9
votes
4answers
18k views

How to export polygon coordinates to CSV (not WKT)?

I am trying to export polygon coordinates from a shapefile to a CSV file, but so far all my attempts have failed. I have found numerous questions and answers about this, but none have solved my ...
9
votes
2answers
936 views

Add an Excel file with a list of coordinates to QGIS as a layer?

I've added delimited text layers to QGIS before with columns consisting latitude and longitude separately. But Now I have an Excel file like: station no parcel no parcel coordinates 63 ...
9
votes
3answers
5k views

Is there a standard for the coordinates of pixels in georeferenced rasters ?

We are working with different raster datasets, and the pixel coordinates are either stored at the center of the pixel or at one corner. The information is usually provided in the metadata, but ...
9
votes
5answers
27k views

Calculate midpoint from a series of latitude and longitude coordinates

I've got a series of longitude and latitude coordinates which represent a building outline e.g. -0.5485381346101759,53.2285150736142 -0.5482220594232723,53.22842450827133 -0.5482298619861881,53....
9
votes
1answer
4k views

If Geographic Coordinates are unprojected coordinates, how can GIS softwares display such unprojected data on a plane?

I have been using ArcGIS and QGIS regularly for about 2 years now, and just recently I was struck by this new thought. If a data set in say, in ArcMap, has been georeferrenced with a Geographic ...
9
votes
1answer
17k views

Calculating View Angle?

I am looking for the most accurate way of calculating the view angle (Azimuth, Elevation) from a reference point (my location) A to another point B. I have the Lat, Lon, and Altitude for each point. ...
9
votes
1answer
10k views

Line vs. Polygon Intersection Coordinates

I am working with Python, Shapely and Fiona... Is there any way where I can give in an input of a line shapefile and a polygon shapefile, and get a result of the intersection points and their ...
8
votes
4answers
11k views

How to use Z-Coordinate in QGIS?

I was mapping an area in Namibia and also tracked a lot of paths on my way with my Garmin device... so I thought it would be nice to see height differences in my area (esp. interesting in the raining-...
8
votes
1answer
3k views

Given Lat and Lon identify if point over land or ocean using R

In R, how do I identify if a point is over land or ocean? e.g. for: set.seed(0) lat <- runif(10, -80, 80) lon <- runif(10, -180, 180) points <- expand.grid(lat, lon) I would like to create a ...
8
votes
3answers
9k views

What are the coordinates of the mysterious hole in Siberia?

I am interested in taking a Google Earth aerial view of the mysterious hole recently discovered in Siberia and perhaps doing some hydrological analysis of the area in a GIS. However, there appears to ...
8
votes
1answer
8k views

Understanding the difference between coordinates projection in OSM and Google Maps in China

I'm looking at the coordinate differences between Google Maps and OSM. I'm a noob in the technicality behind GIS. Having read: EPSG 3857 or 4326 for GoogleMaps, OpenStreetMap and Leaflet How to ...
8
votes
3answers
4k views

Exporting set of lat/long coordinates to SVG using tool or code?

Suppose I have a set of coordinates in latitude and longitude. What would be the easiest way to export those to an SVG file? I'd rather do this programatically (any language or library will do) ...
8
votes
1answer
3k views

How often does Google change geo-coordinates for given address?

I geocoded the address "50 Hurt Plaza Southeast, Atlanta, GA 30303" twice. Once on July 28th, 2014 when I got the coordinates: (33.754208, -84.387272) And again today, August 18th, 2014, and got ...
8
votes
3answers
958 views

What's the difference between coordinateDimension and spatialDimension?

The OpenGIS standard mentions three methods to query the dimensions of a Geometry: dimension(): the inherent dimension of the geometry: 0 for Point 1 for Curve 2 for Surface coordinateDimension(): ...
8
votes
1answer
4k views

Computational most efficient way to convert Cartesian to Geodetic Coordinates

As far as I understand the literature there are several ways to convert a set of geoecentric cartesian coordinates to geodetic coordinates Bowring, 1976 Borkowski, 1989 Lin & Wang, 1995 Toms, ...
8
votes
1answer
25k views

Create a polygon from coordinates in GeoPandas with Python

I was trying to create a simple Polygon from a list of coordinates and export it to multiple formats (including shapefile and GeoJSON) and wanted to automate it using Python. There were some good ...
7
votes
9answers
32k views

Creating shapefile from file with coordinates

How can I make a shapefile of an CSV file with coordinates?
7
votes
2answers
39k views

Calculate bearing between two decimal GPS coordinates

I'm building a virtual tour application that uses custom panoramas in conjunction with Google's StreetView service. With StreetView, you can have 1 to n links at each particular location to move to, ...
7
votes
6answers
15k views

Getting all vertex lat, long coordinates every 1 meter between two known points using PHP?

I am currently using php to try and write code that will take a start point and end point latitude and longitude coordinate pair in decimal degrees and calculate the latitude and longitude of every ...
7
votes
3answers
7k views

Adding “noise” to overlapping X,Y coordinates so no longer in EXACT same place?

I have a series of points representing animal observations. Many of them overlap, having the exact same coordinates, and this is causing me trouble when I want to run some analytical tools which ...
7
votes
1answer
21k views

OpenLayers: Get Coordinates of drawn features

Can someone help in finding coordinates of drawn features? I am using this example OpenLayers website. I need to be able to export drawn objects as set of coordinates. Posting the code from the ...
7
votes
1answer
204 views

Can I project a single set of coordinates that are not in a table or feature class with arcpy?

I have been searching for the easiest way to convert a single set of State Plane Coordinates (in units of "Feet") to Decimal Degrees using arcpy. All the methods I have seen so far involve one of the ...
7
votes
1answer
1k views

Spatial index vs two coordinates indexes

I have a table with two columns: latitude and longitude. I want to get all objects inside a "rectangular" (well, rectangular in a lat/lon coordinate metric) bounding box: min-max latitude and min-max ...
7
votes
4answers
205 views

How do you programmatically read the coordinate display format in ArcMap?

I'm looking for a property (or properties) that will give me the display units and the formatting. I assume I need IMap.DistanceUnits but I can't find the formatting. Is this exposed? I am also ...
7
votes
2answers
40k views

Convert X,Y State Plane coordinates to decimal degrees

I have 1000's of data point I need to convert from North Central Texas 4202 into Lat/Long decimal degrees. Can someone give me a conversion equation so I can quickly convert using excel? I have only ...
7
votes
1answer
2k views

How do you fix Overlapping Lines?

I have a line dataset that contains some lines where the "end points" are actually found in the middle of the line. In the image below, the nodes are shown in green and one of the end points in red. ...
7
votes
1answer
2k views

Coordinate grid display on a rotated map

I have a series of maps that require me to rotate my data frame within my layout screen (north "rarely" points up in these maps). I ONLY want to show east coordinates on the top/bottom and ONLY north ...
7
votes
2answers
3k views

Shortcut to copy current cursor coordinates in ArcMap

Is there a shortcut or an extension to ArcMap 10 that would allow me to quickly copy (to clipboard) the coordinates at the current map position/click? I could implement such a functionality easily ...
7
votes
0answers
3k views

Calculating compass bearing between two GPS coordinates… with a twist [closed]

I'm building a virtual tour application that uses Google's streetview code to render the panoramas into a non-distorted view. Each panorama has 1 to n links where the user can select to move on. I ...
6
votes
4answers
1k views

Is there a way to use a spatial query to invert X and Y coordinates in QGIS?

Original problem : I tend to often invert X & Y in WGS84 lat/long CSV import. I'm wondering now if there is a way not to reimport the original file (as this is the basic solution for points) and ...

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