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.

learn more… | top users | synonyms

2
votes
1answer
38 views

Adding graticules to the edge of the map only in QGIS

I would like to add graticules to a map, once it is in the 'print composer', on the border of the map, and not on the frame (my map insists on being smaller than the frame). I have managed to add a ...
2
votes
1answer
94 views

What do different realizations of the same datum have in common?

Firstly, am I correct in assuming that the process of determining the shape and the size of the spheroid is independent from the process of determining the origin and the orientation? For example, ...
2
votes
1answer
129 views

How to smoothly join two rectangles

I am looking for the Math and steps involved not using a tool. We have PostGIS but its an old version so we are working with the data in Python. Given three coordinates: -107.37, 52.46 -103.24, ...
2
votes
1answer
112 views

How can I show points on the same coordinate as e.g. a bigger symbol in QGIS?

I use QGIS 1.8 for mapping archaeological findings. Some of the findings within one layer are located on the same site and therefore have the same coordinates. Therefore you just see one point instead ...
2
votes
4answers
377 views

Get coordinates from address

I am writing a application which allow users to save a address into database (db) and in the next step it shows all addresses on a map. But in the saving step I need automatically calculate a GPS ...
2
votes
1answer
617 views

Understanding the difference between coordinates projection in OSM and Google Maps

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 ...
2
votes
1answer
155 views

How to flip X and Y coordinates of a grid by GDAL

I have a grid, which has flipped X and Y coordinates (X is represented by Y values and Y is represented by X values). This results in grid being positioned in completely wrong place. How can I flip ...
2
votes
1answer
2k views

Trying to set the OpenLayers MouseOver position to be outside the Map

This is my code and I am trying to obtain the MouseOver to be displayed outside the Map container. <!DOCTYPE html> <html> <head> <title>My Map</title> ...
2
votes
1answer
1k views

How to find bounding coordinates (lat/long) for UTM zones?

I want to error check incoming lat/lng points by checking if the point resides within the given UTM zone. (This would work for the data im using because sometimes there is a missing sign or lat/lng is ...
2
votes
1answer
511 views

Read .DEM (USGS) FIles with C#

I have a huge number of .DEMs and have been investigating how to process them into something useful. Does anyone know how, or even if it is possible to read coordinates and elevation data from ...
2
votes
0answers
23 views

Is it safe to store coordinates on NFC tags always in one CRS and rely on conversion for others

I'm involved in NFC (Near Field Communication) standardization of a record structure for geographic point locations. That will allow to put coordinates on NFC memory tags which can be read with a ...
2
votes
1answer
78 views

Determine when I have crossed state line?

We are currently using the Google Maps API to get route information and total mileage but we would like to determine when we are crossing into a new state. When we return the route information we can ...
2
votes
0answers
129 views

How to add XY coordinates (latitude/longitude) to a DEM raster in ArcGIS 10.1

I would like to add xy coordinates of about 10 sites to a raster. I am using ArcGIS 10.1 and my xy coordinates are on Access 2013 database - saved as .mdb. The steps I have taken so far: 1) In ...
2
votes
0answers
66 views

How to locate a house on the 3D Map correctly?

I've done my 3D map generation in WebGL/THREE.JS project and have an issue with the building locations. I have the data about building position ( its polygon ) from DB server, but first of all I want ...
2
votes
0answers
90 views

Height of the geoid in ECEF coordinates

I know that the relationship of geoid height N and ellipsoid height h to orthometric height H is defined by H = h - N, but what if I have some position in Earth-Centered-Earth-Fixed (ECEF) ...
2
votes
0answers
130 views

PyProj/Proj4 convert geographic to projected coordinates for Geostationary Data

I am trying to convert geographic coordinates (in degrees east/north lon lat) to projected coordinates in meters for geostationary full disc data (GVAR Goes East data from CLASS). To do this, I tried ...
2
votes
0answers
175 views

How to limit a specific area in order to have a topographic 3D map using MatLab?

I am using MatLab, I want to build a topographic 3D map, I am following this guide, I have been doing the steps listed on the section Draping Geoid Heights over Topography, and I do not have any ...
2
votes
0answers
152 views

Plotting X, Y coordinates generated from MySQL database in QGIS

Currently running QGIS 1.8.0 on Mac OS X 10.8.4. I can plot points on a map using the "Add delimited text layer" plugin to get x-y coordinates from a text file. However, I'd like to be able to ...
2
votes
0answers
79 views

Should 2D Positions and 3D Positions be considered conceptually different entities?

Let's suppose we want to model GeographicPositions, described by coordinates or coordinate tuples inside some Coordinate Reference System. Also, these would be put inside some sequence to represent ...
2
votes
0answers
113 views

Comparing two spatial datasets statistically

I'm new to this forum. I'm working on the following problem - I have two datasets. Let's call it dataset A and B. Both of them will contain a set of points like A1,LonA1,LatA1 A2,LonA2,LatA2 .. .. ...
2
votes
1answer
393 views

Getting polygon shapefile node coordinates and point order

I am trying to get the coordinates of each node of a polygon in QGIS. What I basically did is use the following tools: Vector -> Geometry tools -> Extract nodes Vector -> Geometry tools -> Export ...
2
votes
0answers
98 views

Interpolate current Course value of GPS using previous Course values

I have a set of GPS data with Lat, lon and Course. I need to interpolate current value of course, using previous values of Course. The formula I am using is not accurate in curves.In C language I was ...
2
votes
1answer
695 views

Plotting latitude on to a (Mercator projection) SVG representing a country map

I want to convert (google sourced) longitude and latitude coordinates to x and y to place points on a SVG map I can get the longitude converted to X but I can't nail latitude. ...
1
vote
1answer
708 views

Change coordinates of a polygon

I wanted to know whether it is possible to change the coordinates of a Polygon by typing them in. I don't want to have to manually drag them into the right position.
1
vote
2answers
104 views

Coordinates values change for ArcGIS

I have received thousands of location information like below. X= 10°52.579 Y= 078°38.473 I don't have idea in which format is this, please let me know what is the format of this location and ...
1
vote
2answers
180 views

How to remove z & m coordinates from shapes with QGIS? (Or arcgis, grass, gdal, Python…)

I've recently received some parcel data in shapefile format that has z & m coordinates (all = 0.0). The WKT for a typical parcel looks like this: "MULTIPOLYGON (((2672464.560700002 ...
1
vote
1answer
285 views

EPSG:4326, EPSG:3857, JOSM and unprojections

It is said here that EPSG:4326 is not a projection. In my mind, a projection is a transformation of the surface of the Earth producing a flat image, notably a bitmap. We know that WGS84 (World ...
1
vote
1answer
417 views

How to compute mean coordinates?

Can anybody explain how to compute mean coordinates? Regards.
1
vote
1answer
91 views

How to write a expression in field calculator for finding $X and $Y?

I'm trying to calculate the lat/long of points using the Q GIS field calculator.Nathan W suggested to First, save the layer as WGS84 and import it again. Then in the field calculator you can use $x or ...
1
vote
1answer
158 views

generate random world point geometries

I have a world map. I need random point geometry. So, how can I randomly generate point coordinates? Any programming language. Also, I am using SRID 4326. Any programming language.
1
vote
2answers
786 views

how to extract a rectangle corner coordinates in python script

i want to extract a rectangle corner coordinates of a shape file in python script..please suggest me a solution. Thanks in advance, Bhavya
1
vote
1answer
48 views

How to find nearby objects using Easting and Northing range

I have a bunch of objects which have associated Eastings and Northings in format OSGB36 for example: 265397 869562 547297 179002 If I have a starting Easting and Northing, and wanted to find ...
1
vote
2answers
48 views

qgis polygon to coordinates

I have the ordnance survey postcode polygons, i can get the centre point on the postcode (Using polygon centroids) and all the corner coordinates (using extract nodes) Does anyone know how to export ...
1
vote
1answer
47 views

Draw an item from coordinates in QGIS?

Is it possible to draw a line or to draw a triangle or another figure by digit the coordinates of the vertex? I use QGIS 1.8 on windows 7 system.
1
vote
1answer
674 views

List of central coordinates for all countries?

I need a list of the central points 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) etc...
1
vote
1answer
116 views

If I've given two different layers the same CRS, why won't they overlay one another?

I have a "towns" and "state" shapefile for Massachusetts as two separate vector layers in QGIS. I've set the project coordinate system to WGS 84 at the bottom of the screen (next to the "coordinate" ...
1
vote
4answers
554 views

Query Postgis Table with PHP

Would you be so kind as to help me with the following in OpenLayers. I need to be able to use the coordinates from a user click in a postgis query. To catch the coordinates of a click I built a click ...
1
vote
1answer
351 views

Using SRTM data, how to get the coordinates of the peaks visible from a location?

Using SRTM data and a coordinate-altitude database of the peaks, I want to get the coordinates of the visible peaks from my location. I want to make an application similar to this. How is this ...
1
vote
1answer
478 views

USA Contiguous Albers Equal Area Conic

How do you convert from USA Contiguous Albers Equal Area Conic to meters? Or, to latitude and longitude? I am using ArcGIS 10.1, and within it, ArcMap. The shapefile I have reports the coordinates ...
1
vote
1answer
64 views

Calculation to convert db data to Lat/Lng degrees

In a database I have the following Lat/Lng data. I wish to convert it to a readable format. 177514245:34726053 => S 32 7.3947, E 115 51.4245 177513828:34726948 => S 32 7.3052, E 115 51.3828 ...
1
vote
1answer
56 views

How do I add coordinates to a polygon layer to be able to sort the polygons from north to south in QGIS?

I have a polygon file, where each polygon represents one property. I want to be able to sort the polygons from north to south or vice versa. I need them to be sorted in this way when I export them to ...
1
vote
2answers
98 views

From coordinates find country using Python

I have tweets with coordinates. I'm trying to bucket the tweets by country using the coordinate information. I know that I can achieve this using some hosted web services but all of these have API ...
1
vote
1answer
65 views

Defining a line from geographic coordinate points.

On a flat surface we can define any point on line which passes from point1 (x1,y1) to point2 (x2,y2) via simple trigonometry. How can we do that with latitude and longitude of 2 points? Imagine we ...
1
vote
1answer
52 views

FME: how to extract the coordinate of the North West corner

In an FME translation from a polygon geodatabase feature class to a DGN I am trying to place a label in the top left corner of a box. I have tried using CoordinateExtractor to find the coordinates of ...
1
vote
1answer
40 views

Transform an Irish grid reference (29903) into UK grid reference (27700) on insert

I have an insert script to input several hundred points, however some of the points use the Irish Grid Reference system. I have separated these out however was unsure how to convert or transform? ...
1
vote
1answer
65 views

produce a grid of geographic coordinates within 1 mile of each other with QGis or PostGIS

For a given county (bounded box, lets say), I need to get a network of gps points such that each point is 1 mile from its nearest neighbor point in each cardinal direction. The result of this initial ...
1
vote
3answers
123 views

How to export xy-coordinates from a line segment

I need an export of xy-coordinates of line segments (Quantum GIS). I found an answer to a similar question here but that concerned only xy of the first and last vertex of a line segment. But I need ...
1
vote
2answers
254 views

How to extract features with specific coordinates from a ShapeFile?

I would like to extract a number of features from a ShapeFile which match with specific latitude/longitude values. I am interested if/how this can be done with QGIS and ogr2ogr. The output should be ...
1
vote
1answer
159 views

ArcMap 10.1 - UTM Zone Display Mismatch

I've recently noticed that the UTM zone displayed in the Identify box and the "Goto XY" box display a different UTM zone than the one I'm in. I'm working in WGS84 NAD83, Zone 13N but when I use the ...
1
vote
1answer
111 views

Polygon Nodes do not have separate coordinates [duplicate]

I'm attempting to measure the distance of a series of points from a smaller number of polygons. As a first step, I've changed the polygons into points along their border, via the Vector> Geometry ...