1
vote
1answer
49 views

Proj4js Problem in converting coordinates from google mercator

I am a really beginner into web-cartography, so sorry if this subject is rudimentary or basic but I truly search for a long time and I am still stick in it. So the problem is: I don't understand why ...
2
votes
0answers
49 views

Returning distances in meters from Near (Analysis) tool of ArcGIS for Desktop?

I'm trying to write a python program that returns the distance from each point in a set to the nearest road. Specifically, I was looking for any points within 10 meters of the roads. Both sets of ...
4
votes
2answers
57 views

Projected coordinate system for South America

Does anybody have any suggestions for a projected coordinate system for the Northern part of South America? I have a data set that reaches from Venezuela to Southern Peru and I'd like to do some ...
1
vote
0answers
47 views

My map is little bit off

I am pretty new in GIS things and i have been learning how to use QGIS. Most of the maps are fine, but yesterday I went to GIS center at my University and I got the maps of my country that I will be ...
1
vote
2answers
51 views

Shape length distance wrong in Robinson projection

I have a world map in the WGS 1984 Geographical Coordinate System. I want to measure the lengths of borders between countries in kilometers. To get the units in meters, I have first used the Define ...
3
votes
1answer
97 views

Comparing printed nautical charts to GPS coordinates

I'm just getting my head wrapped around the various geodesic systems. I have some (printed) Finnish nautical charts I'm trying to match to GPS coordinates. Given the number of underwater obstacles, ...
0
votes
1answer
87 views

Raster and vector layer in the same CRS don't match

While adding multiple raster and vector layers (and setting them all in CRS WGS84) in QGIS 2.2, they don't seem to overlap. Interestingly enough, only raster files overlap between each other, the same ...
0
votes
1answer
179 views

ArcGIS Conversion Error While Converting ED50 Datum to WGS84 Datum

With ArcGIS for Desktop, I tried a datum conversion of Transverse Mercator ED50 Datum to Transverse Mercator WGS84 Datum. Normally, the difference between two projections is approximately 180 meters ...
0
votes
1answer
31 views

QGIS “transform error” after downloading from OpenStreetMap

Beginner's question. I am working on this tutorial: http://www.qgis.org/en/docs/training_manual/vector_analysis/basic_analysis.html After selecting WGS84 UTM zone 34S in Project Properties, I receive ...
2
votes
1answer
41 views

WGS84 CRS without elipsoid

What's the difference between using CRS defined as +proj=longlat +datum=WGS84 +no_defs and a CRS defined as +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs Will using one or the other pse any ...
1
vote
2answers
55 views

Why does my gpx layer go to the wrong spot even if they have the same CRS?

Help! I am a QGIS beginner with a big problem! I am trying to load a gpx file from Garmin into my map. The project CRS is WGS 84, and the incoming data is in CRS WGS 84. When I look at the bottom of ...
3
votes
1answer
93 views

How to get projected centroids in QGIS?

I am trying to get a centroid for several polygons on a global scale, in a way that it would correctly represent the common centre of all the polygons, taking Earth's curvature into account. The ...
5
votes
2answers
702 views

Stereographic projection of WGS84 ellipsoid on a plane[python]

I would like to ask you for help in following task. What I need to do is to derive local x,y coordinates from latitude, longitude, applying stereographic projection of WGS84 ellipsoid on a plane, ...
2
votes
2answers
286 views

Stereo 70 where is it?

I have ortho photos of Romania in Stereo 70 and GPS data in WGS84 of the same country : I want to associate the two series of data. At the moment, I can't find Stereo 70 in the list of CRS : does it ...
3
votes
1answer
751 views

How to convert to Australian Height Datum from Google Earth elevation?

I am trying to figure out how to convert from Google Earth elevation to Australian Height Datum (AHD). Google Earth's elevation / altitude is based on The vertical component (altitude) is measured ...
3
votes
1answer
101 views

Rhombus shaped pixels when viewing an image referenced in WGS84

Following the Question What is the projection of WGS84 in GIS software?, in the comments section of the answer http://gis.stackexchange.com/a/73578/5256, Jake very well explains that Because the ...
4
votes
4answers
2k views

What is the projection of WGS84 in GIS software?

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. ...
2
votes
1answer
933 views

Canvas Units to Degrees, Minutes, Seconds

I am using the WGS 84/UTM coordinate sysytem. When I go to > Project Properties / General / Canvas Units to Degrees, Minutes, Seconds my coordinates are wrong. I am using QGIS 2.0.1
2
votes
1answer
241 views

What is the range of numbers for coordinates in geographical coordinate systems

Up to now I thought the range of values in the geographic coordinate systems was: Latitude (S-N): -90 to +90 Longitude (W-E): -180 to +180 I have set the coordinate system of my ArcGIS data ...
3
votes
1answer
485 views

Are these two OGC WKT projections the same? And if so, why are their reference strings different?

So here is the .prj text of a federal shapefile dataset of all public airports in its native OGC WKT format: ...
2
votes
0answers
117 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
1answer
2k views

Trying to convert coordinates from WGS84 Web Mercator Auxiliary Sphere to WGS84

I've been struggling with this for way too long now. I've got some data that was georeferenced in the WGS84 Web Mercator Auxiliary Sphere that should have been done just in WGS84. The Auxiliary ...
1
vote
1answer
282 views

Conversion from NZMG to latitude and longitude

I want to convert NEW ZEALAND MAP GRID coordinates i.e. Northing and Easting into WGS84 coordinates i.e. Latitude and Longitude. I have searched on internet but there is no proper explanation of how ...
2
votes
1answer
247 views

Transformation from WGS1984 to ITRF2008

We are using Projected Coordinate System: Ain_el_Abd_UTM_Zone_39N (Transverse_Mercator) in our GPS Devices and have valuable Coordinate data. Can I change the projection of this data this to WGS 1984 ...
1
vote
1answer
743 views

PROJ4 C++ API: Amersfoort RD New to WGS84

I try to convert between dutch RD New (EPSG:28992) and WGS84 (EPSG:4326) via PROJ4 C++ API. On the console this works with: cs2cs +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 ...
3
votes
1answer
3k views

What is the relationship between ITRF and WGS84?

Why are there people saying that "I am using WGS84(ITRF96)"? There are newer version of ITRF. Will WGS84 follow it? If so, what will be the influence to us?
1
vote
3answers
2k views

How to convert Lat & Long from Onemap.sg to Google Maps

I have a set of address for Singapore, I would like to take the Lat & Long from onemap.sg (SYV21: X, Y / Easting, Northing) and then store it in my databse , convert into (WGS84: Longitude, ...
7
votes
2answers
2k views

How is EPSG:4326 data 'projected' in a 2D map?

I like to think I'm relatively well-versed in datums, projections, and coordinate reference systems, so if this is a stupid question I will suffer eternal shame. OpenStreetMap data is stored in WGS84 ...
2
votes
3answers
3k views

Code to convert WGS84 coordinates to British National Grid Easting/Northings

I'm looking for some code, ideally C#, to convert a WGS84 coordinate to British National Grid Easting and Northings. Does anyone have this to hand? I tried converting the Javascript code here: ...
8
votes
3answers
342 views

Global grid, which reference system to use?

I have seen a couple global studies using WGS84 as geographic reference, with the problem that the area of raster cells is not constant. Which reference system would you use for a global analysis in ...