A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane
15
votes
2answers
840 views
How does one calculate distortion on Equirectangular Projection?
I am trying to calculate distortion so I can distort overlaying text and forms to precisely match an image of an equirectangular projection.
So, how does one calculate the distortion at a given ...
1
vote
2answers
61 views
Mapping elements in a warehouse
I am new to GIS. For a small project I want to map elements in a warehouse and want to find the location of the elements later (e.g. nails are located at x,y).
Now I am wondering what kind of ...
0
votes
2answers
78 views
How do I reproject one raster to match another's in GRASS
I have two raster layers, A and B, which have information about the same location but have different projections and datums.
How can I reproject layer A to match the projection and datum of layer B?
...
5
votes
1answer
220 views
Determining Natural Origin for a GeoTIFF file (Lambert Conic)
I am trying to display an existing GeoTIFF file (from the FAA WAC set) in an application that requires the GeoTIFF NaturalOriginLongitude tag (FalconView 5.1.1). There are some older files in that set ...
2
votes
1answer
97 views
Find projection of a point to a line
I have a segment defined by 2 LatLon points(A and B) and a third LatLon point (C).
I need an alghorithm, formulae, or some code to find the projection point of C on the segment AB (call this point D) ...
1
vote
1answer
43 views
When is a projected length calculated via a pythagorean distance more accurate than an ellipsoidal length?
I'm using spatialite 3.0.1 with the following test data (in EPSG: 4326):
Name astext(geometry)
---------- --------------------
Belitsa POINT(23.563 41.947)
Malko Tarn POINT(27.533 ...
1
vote
1answer
87 views
MMQGIS: How to make grid layer in meters not degrees?
I've read several of the posts on here pertaining to MMQGIS Create Grid Layer option, but I have not found information on how to make the grid based on meters veres degrees. I know how to manipulate ...
0
votes
1answer
42 views
Wrong object size after projecting spatial data from one coordinate system to another
I am having problems reprojecting items in ArcMap 10.1 from British National Grid To WGS84. (WKID: 27700 Authority: EPSG to WKID: 102100 Authority: ESRI)
All Polygon Layers I project [I use Project ...
0
votes
1answer
81 views
Problem Overlaying layers in OpenLayers
I have a html page with 2 WMS layers.
The first is one Base Layer , & the second is my personal WMS feature. I load it from Geoserver. The problem when I add the 2 layers I do not have the ...
0
votes
1answer
71 views
OpenLayers WMS - TypeError: this.resolutions is undefined
I'm trying to setup a map with WMS and WFS Layers by using Geoserver.
However, when I'm combining WFS and WMS (with some Google basemaps) together in one map I got following error in Firebug:
...
0
votes
0answers
46 views
How to find out what projection my data is using?
I have a set of data that I created from gps locations of images. The locations are in decimal. I don't know what projection was used when the data was captured.
I used QGIS to display the data with a ...
0
votes
0answers
31 views
need info on GeoTIFF projection keys
I am a programmer (not a cartographer!!) developing an application which needs to read and write GeoTIFF files. I have a number of questions about those GeoTIFF keys which are related to projections.
...
0
votes
0answers
28 views
QGIS: Unable to project raster layers correctly on a Toshiba Tecra 64# Win7
I know how to project a raster, I can do it on other machines. On this particular machine the raster loads but are no where near the correct position as if the datum is on another planet.
0
votes
0answers
57 views
How to get Earth radius in pixels?
I need Earth radius in pixels for use in Mercator projection. Well let's say that our map's height is 1478 pixels and distance between 0 pixel and 1478 pixel is 2.52 degree. Radius is distance from ...
0
votes
0answers
49 views
I want to change EPSG:4326 to EPSG:900913 using C# for a set of uploaded shapefiles
I have written some code (using help from these pages) that uploads a directory full of shapefiles to a geoserver using C#. The uploaded shapefiles are set to EPSG:4326 however I would like them to be ...
0
votes
0answers
53 views
Reprojecting raster data from a rotated pole grid
I have some raster data (ASCII grid files) that use a custom rotated-pole projection, that I'd like to reproject into something more useful, such as lon/lat WGS84. A description of the grid projection ...
0
votes
0answers
50 views
How to join edge of International Date Line in world file?
I am currently using world file (http://www.ngdc.noaa.gov/mgg/shorelines/gshhs.html) for international boundary information.
Now I have difficulty with map projection that the map ends with ...
0
votes
0answers
45 views
include the robinson projection into open layers
I need to include a robinson projection into openlayers, but i found no epsg code for it.
i have this spherical mercator projection at the moment and need to change it, but i dont know if it is ...
0
votes
0answers
92 views
Reprojecting coordinates and geoJSON in leaflet
I have a Leaflet map in default projection and a wms layer also in default (web mercator) projection. I would like to add polylines and a geoJSON layer to my map, but the coordinates are in EPSG4326. ...
0
votes
0answers
33 views
export WebMap in a different projection than the WebApi
I am quite new to the Flex WebApi world. I am using the Flex WebApi and have set up map templates to print maps out to my own template as a PDF. In my template I have the Map grid set. When I eport ...
0
votes
0answers
106 views
How to re-project the EASE (Equal Area Scalable Earth) grid with a ~25 km cylindrical projection to WGS84 0.25 degree?
I have nc files ,here is one file https://echange-fichiers.inra.fr/get?k=LUfqiyO1Dl7az5bihnS. from the metadata ,the projection is cylindrical and the resolution is 25 km:
...
0
votes
0answers
227 views
XYZ map doesn't calculate the correct tile URL
I have the following code:
Proj4js.defs["EPSG:31258"] = "+proj=tmerc +lat_0=0 +lon_0=13.33333333333333 +k=1 +x_0=450000 +y_0=-5000000 +ellps=bessel ...
0
votes
0answers
72 views
Proj4js accuracy compared to Proj4
Is there any lost of accuracy in reprojecting using Proj4js in the browser (compared to using server side Proj4 in Mapserver ) ?
0
votes
0answers
68 views
How can I convert a Winkel Tripel map to a Mercator map?
I have a map of the world (a PNG file) which uses Winkel Tripel. I'd like to convert it to Mercator. I would just use pyproj, but it lacks an inverse "wintri" projection.
0
votes
0answers
326 views
How to convert map coordinates to lat long values in Lambert projection with WGS84 datum using Java?
I want to convert map coordinates values to latitude,longitude values. The image is in Lambert Conformal Conic projection with WGS84 datum, WGS84 ellipsoid. Please suggest to me the formulas involved. ...
0
votes
0answers
65 views
Changing projection of base layer
normally we change projection of vector data for displaying it over google base map. Similarly is it possible to change the projection of base image tiles map? if yes, how we can do that, any ...
