A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane

learn more… | top users | synonyms (1)

13
votes
2answers
2k views

How to reproject raster from 0 360 to -180 180 with cutting 180 meridian

I have a geotiff raster image that has a coordinate system with longtitudes from 0 to 360. The horizontal center of the image is 180 longtitude. See image below: I want to transform it to EPSG:4326 ...
3
votes
1answer
509 views

How to reproject a raster to Winkel Tripel projection?

I'm trying to project a raster map (in ASCII grid format) from longlat to the Winkel Tripel projection. But I'm running into errors, for instance gdalwarp won't accept the proj-string. $ gdalwarp ...
4
votes
2answers
2k views

German coordinate system from Lat/Long

I have WGS latitude and longitude for data points near Munich and I'd like to use a grid-type coordinate system, like the Ordnance Survey grids in Ireland or the UK. What coordinate system do you ...
2
votes
1answer
363 views

What coordinate system is this?

I just found a dataset of trees in San Francisco, but I'm unable to determine the system used for the coordinates. Here are some samples: 5998894.045593,2119007.035323 ...
2
votes
0answers
583 views

Help converting projection/coordinates to Google Earth

I'm trying to program a GPS style tracker for a simulation game but I'm having a hard time figuring out how to transform the game's coordinates into Google Earth's. The game's world is flat and has ...
2
votes
2answers
280 views

How to project US States in Transverse Mercator [duplicate]

Possible Duplicate: Layers having the same coordinate system should overlap, but they don’t. What’s wrong? I created two different MXDs, one for City of Tucson and another for US States. If ...
1
vote
2answers
356 views

Recovering Latitude and Longitude from Albers to Compute Distance

I have a shapefile of U.S. counties in USA Contiguous Albers Equal Area Conic. I want to do distance calculations. For example, distances from one county to another. I do not know how to interpret ...
2
votes
1answer
2k views

Import GPX to QGIS with WGS84 [closed]

When loading a GPX-File in QGIS it is not referenced on WSG84. It´s shown with wrong coordinates. Settings are WSG84.
2
votes
1answer
62 views

What is the purpose of having a separate Layer property for sphericalMercator?

The Beginner's Guide to OpenLayers 2.10 says the following: sphericalMercator {Boolean} This property determines if the map should behave as a Mercator-projected map. Setting this to true ...
2
votes
1answer
350 views

What is the expected margin of error for points plotted on EPSG:3857 projection?

I am using the projection EPSG:3857 to plot out points on the map. Since the Earth is closer to the shape of an ellipsoid instead of a sphere, I am interested to find out what is the range of error if ...
0
votes
1answer
240 views

Setting projection to a geotiff file when it's shown as Unknown

I have a geotiff file that has no CRS in the metadata but I know that the CRS of the raster is WGS 84 UTM 22 N. How can I modify the geotiff file to have the CRS WGS 84 UTM 22 N in the metadata. ...
1
vote
1answer
788 views

OSM Map projection doesn't seem to change

I have the following OpenLayers map: Proj4js.defs["EPSG:31258"] = "+proj=tmerc +lat_0=0 +lon_0=13.33333333333333 +k=1 +x_0=450000 +y_0=-5000000 +ellps=bessel ...
1
vote
0answers
87 views

OpenLayers doesn't understand Mercator map measured in degrees?

I have access to a map server that takes a bounding box measured in degrees, and returns a map, projected in Web Mercator. I'm having trouble configuring OpenLayers to use a Mercator projection that ...
6
votes
1answer
197 views

Is there a difference between projecting shapefiles then rasterizing & rasterizing shapefiles then projecting?

I currently have a project where I rasterize shapefiles into simple presence/absence (1 & 0) rasters and then add each one to a running total to create a total richness raster at the end. The ...
2
votes
2answers
724 views

How do I import specific Coordinates from Namibia in QGis?

I have a map here with Coordinates from the Schwarzeck Map Datum Format 1903. They have the following format e.g.: y: 41 944,31 x:363 810,71 I want these point to be pictured in QGis... how is it ...
1
vote
0answers
218 views

Project tiles from custom imagery in transverse mercator with OpenLayers

I have the following parameters of a custom imagery and I need to set-up a layer in OpenLayers with which I would project the tiles properly from this imagery. TransverseMercator ellipsoidName=WGS84 ...
2
votes
1answer
1k views

Defining datum for Lambert Azimuthal Equal Area and converting to geographic coordinates

I posted this question to a specialised mailing list for spatial data analysis using R here but didn't recieve a response. I am working with shapefiles and rasters in R, and I am unsure if I am ...
1
vote
0answers
282 views

A WMS layer fails to show at some scales

I am tring to overlay my WMS layer on Google but at a particular scale it doesn't show the data of my layer. What can be the problem? <html xmlns="http://www.w3.org/1999/xhtml"> <head ...
1
vote
0answers
319 views

ScaleLine shows NaN for LCC projection

I have used openlayers along with geoserver. My Map is having LCC projection by default, but SRS is EPSG:4042. The problem is that the scaleline shows NaN in meter as well as feet. How can I correct ...
2
votes
1answer
2k views

Mapping x, y pixel coordinates to latitude and longitudes on the WGS84 datum

Apologies in advance for the long question, I am fairly confused at this point and I figure if I show my thought process any flaws early on in the piece can be more easily pointed out. I have a grid ...
1
vote
1answer
219 views

Problems with matching layers with different projections

I have two layers with the following projections: Monte Mario IT1 UTM* Anyhow, I followed the instructions (open the project, set the projection, select on the fly projection, load the layers but no ...
0
votes
1answer
1k views

lonlat from geometry point gives strange result

I added a vector layer to my main map with the controls like the example from openlayers: http://openlayers.org/dev/examples/draw-feature.html Now when I want to get the resulting lonlat from the ...
3
votes
0answers
548 views

Get tile URL with projection different than 900913

I have the following code, which should display a slippy map showing tiles producted by me with mapnik: Proj4js.defs["EPSG:31258"] = "+proj=tmerc +lat_0=0 +lon_0=13.33333333333333 +k=1 +x_0=450000 ...
2
votes
2answers
538 views

GeoTools Oblique Mercator Example

I would like to use the Oblique Mercator projection in GeoTools. I'm currently using a WGS84 Mercator projection like this: final CoordinateReferenceSystem wgs84CoordSystem = CRS ...
3
votes
2answers
659 views

Looking for formula for the Robinson projection

I'm looking for a source that describes how the Robinson projection is calculated. I'm going to use this for converting long/lat into Robinson coordinates in both R and in javascript.
1
vote
1answer
889 views

When I import polygon kml layer, how do I change projection and offset to correct for GMT wrap?

I created a polygon in Google Earth and saved to kml. After importing as a vector layer, where the polygon crosses the prime meridian, the polygon wraps around the world. So far, I have figured out ...
1
vote
1answer
529 views

Geoserver and SRS

I have a very basic problem, and please bear with me since I'm new to GIS. I have geoserver installed in a Ubuntu Box and installed a few maps in shapefile. The maps were originally in ArcGIS format ...
8
votes
2answers
783 views

How to determine projection parameters when customizing a projection

I am trying to customize an Albers and a Hotine Oblique Mercator (HOM) projection to minimuze distortion in the region I am analyzing. The region extends from about 51 to 62 degrees latitude, covering ...
15
votes
2answers
3k views

Calculate distortion outside a UTM zone

One of my colleagues is working with data that is spread across two UTM zone. The majority of the data is in one zone, with a few outliers in another zone. He would like to know what the area ...
6
votes
1answer
1k views

Python script to convert Lat Long to ITM (Irish Transverse Mercator)

I am currently working on a python script that converts Lat Long (WGS84) to ITM. The formulas used are based on a paper published by OSGB (Appendix B): ...
1
vote
1answer
321 views

Project layer with custom projection

My ultimate goal is to know UTM and UTM Northing and Easting. The data can be anywhere in North america. I calculated UTM using arcpy tool (arcpy.CalculateUTMZone_cartography) and I tried to truncate ...
3
votes
1answer
722 views

Calculate bounding box + buffer for rendering a map tile with mapnik library

Mapnik library has a Projection object (I'm using Python bindings): spherical_mercator = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null ...
2
votes
1answer
209 views

domain for transverse mercator projection, using proj.4

I have to apologize for the naive question -- it's my first encounter with projections and this software package, and I intend to use it for a non-geographical application (hence I work on a unit ...
3
votes
2answers
4k views

Why does QGIS scalebar show a wrong scale?

I'm using QGIS 1.7.1 and have added a scalebar. The scalebar usually displays in degrees, unless I switch the map's projection to meters, in which case the units are display in cm. This is not ...
3
votes
3answers
2k views

Rendering a shapefile with a custom projection in GeoTools

I have an image, a shapefile, and a method which can translate an x/y pixel location from the image into a latitude/longitude point or vice versa. I'm trying to use Geotools to render the shapefile on ...
3
votes
1answer
298 views

Is there no EPSG code to use for Behrmann equal-area projection in ogr2ogr?

I'm trying to use ogr2ogr to reproject some shapefiles. The projection I wish to use is Behrmann equal-area. I cannot find an EPSG code to use for the '-t_srs' part of the syntax. Is there any way ...
2
votes
3answers
3k views

Problem with spatial reference system / shapefile projection

I am new to using QGIS and having some problems getting some shapefiles to project correctly. I am using publicly available shapefiles for New York City municipal boundaries found here: ...
6
votes
1answer
261 views

What's a robust strategy for displaying 3D map data for navigation?

3D map data, specifically the kind you see on GPS units, or more recently on smart phones, almost always features a 'HUD' like view, which I'm trying to implement in an application of mine. I have ...
3
votes
1answer
2k views

How to perform datum transformation in ArcGIS server REST API exportmap

I have a ArcGIS server 10.0 mapcontext in one projection (swedish grid sweref99 TM) which uses its own datum, also named Sweref99 . When I use the REST API's map service export function I want to ...
2
votes
1answer
315 views

Mercator Didn't work on Geoserver

Got some problem with Mercator in Geoserver, I tried to display Flight Information Region that has been stored in my Postgre. The result is more likely drawing using Cartesian projection: I tried ...
3
votes
1answer
607 views

How to solve Projection Problem at client side

I want to discuss a scenario here to all. I have developed a Web mapping application in OpenLayers and GeoServer. The customer give us shapefiles with native projection SWREFF99_1330 (EPSG:3008). ...
3
votes
1answer
1k views

Mapserver, TMS, Scales zoom levels and how to deal with all of it

I have a whole bunch of data in my db that I need to draw at different zoom levels using Mapserver. Everything uses a 4326 SRID. My (custom) client, will fetch the data using 20 TMS zoom levels and ...
1
vote
0answers
2k views

How to project geographic coordinates (lat/long) to a cartesian system (albers equal-area)?

I am using this matlab package http://www2.ocgy.ubc.ca/~rich/map.html#examples to project the latitudes,longitudes of my data to a specific projection. For this particular case I am using albers ...
5
votes
1answer
661 views

Custom Geographic Transformation on QGIS

Is there a way to create a custom geographic transformation with specifics parameters in QGIS like in ArcGIS? Okay, I want to tranform SAD69 system into WGS84. Well, I'm in doubt because in ArcGIS ...
2
votes
3answers
2k views

Why are the tile coordinates different in Google maps and Google earth?

I have a .NET application that typically uses the standard Google Maps JavaScript API V2. Within this application I am using a GTileLayerOverlay to add my own custom dynamic tile layer. function ...
2
votes
1answer
100 views

Need software to read geo information from tif

I am trying to verify the lat/lon and ECEF values that I have determined for a very specific and unusual situation (a geotif file), and it would be great if I could find some software to read them. ...
6
votes
1answer
601 views

Create Mercator map with arbitrary center/orientation?

I want to see a Mercator map where I choose what latitude/longitude is in the center and what direction is "north". In some sense, a Mercator map of a rigid rotation of the globe. Does such a ...
4
votes
2answers
8k views

Arcmap 10 feature with undefined coordinate system projects incorrectly when projecton is defined

I'm fairly new to GIS, and am slowly feeling my way through ArcMap 10. I have run across a problem defining the Geographic Coordinate System and projection for a feature (the feature currently has an ...
1
vote
0answers
116 views

How to compute a map-to-screen transformation?

Every projection calculation I have come across dealing with the Lambert Conic projection converts the given Lat & Long to meters. So now the magical question: how on earth do you take the meters ...
5
votes
3answers
2k views

Convert an arbitrary meta-data-free map image into QGIS project

My background: experienced programmer, amateur historian, complete beginner to GIS (so I'm using QGIS). I did learn to use the QGIS georeferencer tool though. The input: suppose I have an image like ...