
How to synchronize the marker's rotation field with the angular distortion in the map projection
20131215
I'm Using QGIS 1.8.0 to plot a global dataset showing the positions of aircraft in flight. The data I have are .csv files with three columns: Latitude, Longitude, and angle of travel. I assign the "angle of travel" column of data to the rotation

What is the right solution (and map projection) to compute distances between points located all over the World?
20110128
After my study on map projection I realized that it is very difficult to choose a projection that allows to compute simultaneously the distances between a great deal of points if these points are located all over the world. Equidistant projections al

Bertin 1953 map projection settings
20110309
I am trying to use the Bertin 1953 map projection, as described in the book "Semiology of graphics" by Jacques Bertin. But I can't find the settings in any of my GIS software. Does anybody have a solution ? Thanks, Luc Solutions

Map projection in OpenLayers
20111118
I want to overlay some data whose projection is WGS84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows: map = new OpenLayers.Map('map', { numZoomLevels: 20, projection: new OpenLayers.Projection("EPS

Which world map projection allows comparing countries by shape and size?
20120303
The Mercator projection increases scale along with the latitude. Greenland seems larger than Australia, when in fact it is much smaller. The equalarea projections however stretch shapes away from the Equator. I suppose that there exist no projection

which map projection should I use to calculate distance in Poland
20120319
I'm using/learning geodjango + postgis, and I'm trying to calculate distance between 2 cities in Poland. First using WGS84/4326 I define 2 points, and then after transforming this points into spherical mercator 900913 i get distance which is about 40

How do I use Proj4js or other technique to make custom map projections with google.maps.Projection?
20120418
I'm using Google's Projection class to try to convert my map projection from the default spherical mercator to something like Lambert Conformal Conic. I was previously adapting the code from this example to the v3 API, but am getting some weird drawi

Evaluating map projection scale error
20120906
This is related to a previous question I posted. I am trying to quantitatively evaluate scale distortion associated with choosing different projection center, center azimuth, and scale factor values for a Hotine Oblique Mercator (HOM). 1) Is the foll

OSM Map projection doesn't seem to change
20120906
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 +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 +units=m +no_defs";

Is the quadrilateralized spherical cube map projection the same as Snyder's cubic equal area map projection?
20121113
Is the quadrilateralized spherical cube map projection [1] the same as Snyder's cubic equal area map projection [2]? I know both are equal area polyhedral map projections ( http://www.progonos.com/furuti/MapProj/Dither/ProjPoly/projPoly.html ) based

Is there a name for map projections that produce two disks?
20130122
I've seen lots of world maps in the shape of two disks that touch, each one a separate projection of one hemisphere onto a disk  usually the Western Hemisphere and the Eastern Hemisphere  so together the full map covers the entire globe. Is there

Performance loss for OpenLayers EPSG transformation? Storing GeoJSON coordinates in lat/lon or in native map projection?
20130419
For a project the map projection is EPSG:32468 (tiles). On top of the map, two or three GeoJSON LineStrings should be displayed using OpenLayers. Each LineString has about 1500 coordinates. Actually, I would like to store the coordinates of the GeoJS

Shadow mapping with deffered shading for directional lights  shadow map projection problem
20130922
I'm trying to implement shadow mapping to my engine. I started with directional lights because they seemed to be the easiest one, but I was wrong :) I have implemented deferred shading and I retrieve position from depth. I think that there is the big

Arctic EPSG:4326 map projection?
20131031
Does anyone know of a source for an Arctic EPSG:4326 map projection? Obviously I'm a GIS newbie, so gentle pointers in the right direction appreciated! It's a long story. I have some arctic ice data that I'd like to visualize with Tableau 8.0 which a

Equal (ish) areas Map Projection at the Tropics
20140222
What map projection (noninterrupted) preserves areas well for the entire tropical region? I am thinking of using a Cylindrical Equal Area or a sphere based version of a Cylindrical Equal Area or Mollweide (http://spatialreference.org/ref/esri/54009/

Is it possible to render tilebased web mapping projects in any other projection than web mercator?
20140323
Webmapping technology has to a large degree adopted the webmercator projection as the standard projection for displaying geographic objects with interactive mapclients. This is due to many factors including the mathematical simplicity of the cylin

How to use Google Maps projection with GeoDjango/PostGIS
20140527
I am building a web service with GeoDjango which involves user submitted events including a location. I created a model field for my location using django.contrib.gis.db: location = models.PointField(srid=900913) I chose to specify 900913 as I read t

Map project a raster having separate latitude and longitude raster bands
20140625
I have a satellite image where one of the channels is a raster having the longitude values, another channel a raster containing the latitude values. What would be the best way for map projecting such files? Is there some standard routines or tools (I

Accurate local map projections
20140707
Is there a map projection that can accurately represent reality at a local area, i.e. when transforming the map could I choose an area that I care about accuracy and allow distortions elsewhere? Like this map: I want to choose where the distortion ha