A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane
5
votes
0answers
221 views
Evaluating map projection scale error
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 ...
4
votes
0answers
186 views
How can I improve my Georeferencing results?
Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
3
votes
0answers
184 views
VBA Convert decimal degree to Meters button
I have 2 data frames one which has WGS data in it and the other OSGB1936. I am trying to create a button where the user can input decimal degrees (WGS) and it will zoom them to that location in ...
3
votes
0answers
239 views
How to define Winkel Tripel in proj 4.8.0?
I have QGIS with proj 4.8.0 installed. I'd like to add Winkel Tripel projection which seems to be defined as
+proj=wintri
But that definition string does not work. Is this a bug in my proj version, ...
2
votes
0answers
22 views
Projection string for GOES-WEST
Full-res, full-disk GOES-WEST images are available from
goes.gsfc.nasa.gov. Is it possible to rig up a projection
string for these images?
We know the center pixel is at (0N, 135W) and the
satellite ...
2
votes
0answers
55 views
Proj4 inconsistent longitude after projection
All coordinates expressed in this question are (longitude, latitude), the default for proj4. London is at (-0.1460838, 51.5170986), and San Francisco is at (-122.419302, 37.775549). According to the ...
2
votes
0answers
147 views
Mapserver+openlayers: displaying a shapefile with Cylindrical Equal Area (Lambert) projection
I have some shapefiles in "World Cylindrical Equal Area (Lambert) projection".
The .prj reads:
PROJCS["World_Cylindrical_Equal_Area",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_
...
2
votes
0answers
83 views
projection discrepancy with gdal (1.9) and proj4
I boiled the problem down to that python example:
import sys
try:
from osgeo import gdal
from osgeo import osr
except:
import gdal
import osr
if __name__ == '__main__':
version_num = ...
2
votes
0answers
79 views
Projection declaration in dojox.geo.openlayers possible?
I am trying to integrate some maps of my own into the dojox charting demo and I had success in exporting a shapefile (externally, i.e. with my own parser) to the dojo JSON map format. The map is in ...
2
votes
0answers
54 views
Recommendations on universal projection API or algorithm for ArcObjects?
As asked on the esri forum here, we are trying to convert a geometry from any spatial reference to any other spatial reference. We have tried the default IGeometry.Project(target_spatial_reference) ...
2
votes
0answers
252 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
0answers
85 views
1944 Cyprus Grid coordinate data projection problem in MapInfo
I have coordinate data from the 1944 British Army General Staff, Geographical
Section (GSGS) Cyprus map which was cast on the Cassini projection, but was referenced to the Clarke 1880 ellipsoid where ...
2
votes
0answers
82 views
raster data expressed as percent
I downloaded NDVI greeness data from the USGS Integrated Vegetation Mapping Viewer. In the metadata it says that visual greenness values range from 0 to 100. My data is from the period ending 3/5/12 ...
2
votes
0answers
252 views
Arc by center point in PostGIS does not fit the circle
I'd like to store a GML ArcByCenterPoint in PostGIS. I can work out the start, middle and end points required by the CIRCULARSTRING type and all seems to be OK, except that when I visualise the arc it ...
2
votes
0answers
748 views
Converting projected coordinates to google maps pixels
I have a single polygon in a local projection system. I would like to convert that polygon into an image that can be used as an overlay on google maps. I understand that it may be better to use ...
1
vote
0answers
39 views
Using gdal to convert from UTM to equidistant lat/lon
I am getting rather confused with converting a UTM gridded dataset into a equidistant/rectangular latlon gridded dataset. Can anybody help me?
I have a UTM set with the following projection:
...
1
vote
0answers
55 views
QGIS: Different projection result for on the fly and transformation
I am a bit confused about the result of a re-projection/transformation of a raster in QGIS 1.8 (Lisboa).
WGS84 to WGS84/UTM34N. When I use the 'on the fly' transformation the resulting raster has a ...
1
vote
0answers
27 views
how to get correct geo reference system for a VMap
I am new to GIS, trying to read the GeoRef System for VMap by using the following code:
OGRSpatialReference *ref = layer->GetSpatialRef();
if( ref )
{
QString georefSystem = ...
1
vote
0answers
42 views
How to import multiple shapefiles each with different source projections to postgis
I have a couple thousand .zip files each with a .shp, .dbf, .shx, and .prj inside them that I want to load into postgis. The problem is, they have many different source projections (each defined in ...
1
vote
0answers
45 views
Projection for Tracking a Vehicle
I'm looking for the best coordinate system projection to use for cartesian calculations while a vehicle is running from its starting location to about 100 miles from that spot.
The offline format ...
1
vote
0answers
75 views
Lines as Great circles on a map
How can I get line features to appear as great circles on a map, instead of straight lines?
Thanks,
1
vote
0answers
54 views
What is a radar projection?
Trying to overlay a radar image(radar projection) on a mercator projected map, but have no idea about what a radar projection is.
So here are my quesions:
What is a radar projection?
What's its ...
1
vote
0answers
97 views
What is UTM Zone 0?
I am currently working with some roadway link data and it is being projected in UTM.
After importing the shapefile into GRASS I can view the map and it looks correct but when I view the projection ...
1
vote
0answers
78 views
Converting altitude in feet to pixels on a mercator map image
I know the question might seem farfetched given that the map is 2d. But I essentially want to project items-aircraft-above the map and I would like their altitude to be vaguely 'realistic' in terms of ...
1
vote
0answers
109 views
How to overlay 3 different layers using ArcMap
I have to overlay 3 different layers called "Bacino Isonzo Perimetro", "Bacini Tributari Isonzo", and "Isonzo" in ArcMap. Layers'properties are shown below.
BACINO ISONZO PERIMETRO
Data Type: File ...
1
vote
0answers
78 views
adding WMS service to application ArcGIS JS api
I've got map in projection: 4326 (WGS-84) when I try to add WMS layers which is in different projection I always get connection timeout Do you know if I could change WMS projection to set it up ...
1
vote
0answers
97 views
Adding X,Y data and viewing with existing shape file
Excuse me for a simple question. I have CSV files of X,Y data (in decimal degrees) that I want to add to a map and view with a shapefile of level III ecoregions that I downloaded from the USGS ...
1
vote
0answers
66 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 ...
1
vote
0answers
86 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
...
1
vote
0answers
162 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 ...
1
vote
0answers
124 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 ...
1
vote
0answers
166 views
Imported netcdf file doesn't project correctly - help!
I have 360 netcdf files (.nc) that I need to import into ArcGIS. They hold monthly historical climate data in the U.S. When I tried to import one, using the Make NETCDF Raster Layer tool, the ...
1
vote
0answers
382 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 ...
1
vote
0answers
93 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 ...
1
vote
0answers
188 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
136 views
On the usage of Proj4Js->tmerc.js
I am using "proj4js & open layers" for my mapping.
I got projection & datum (which is based on "Transverse Mercator") of a local plane and
this plane is part of a grid which returns ...
1
vote
0answers
237 views
Conversion From Transverse Mercator To Longitude & Lattitude
I have to transform (7-parameters datum transformation) coordinates from northings & eastings to lattitude & longitude.
Following are details of source coordinate system(i.e. northings & ...
1
vote
0answers
206 views
How do I use Proj4js or other technique to make custom map projections with google.maps.Projection?
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 ...
1
vote
0answers
110 views
How to show an array of 2d points/polygons in Polymaps (Cartesian coordinate system)
I need to display these 2d points/polygons (Cartesian coordinate system) on Polymaps with GeoJson layer.
I do not use the other layers.
Do I need to convert xy coordinates to the lat lon? If so, how?
...
1
vote
0answers
243 views
Geoserver tiles mismatch
I tried to get WMS tiles from geoserver like
/geoserver/gwc/service/tms/1.0.0/layername@EPSG%3A4326@png/15/19142/9530.png
or with another projection
...
1
vote
0answers
126 views
I am getting a blank layer preview from geoserver after Quick Exporting my shapefile to postgis and then getting postgis to point to geoserver
What could be the potential problems? Looking at the layer's data fields/form the one thing that isn't filled is the Native SRS and its source, but I have already passed in the projection info as it ...
1
vote
0answers
314 views
mixing lon/lat and mercator layers in a MapServer .map file
I have a basic question about my MapServer .map file, which has two layers, each with a different coordinate system, longlat vs. mercator.
See my .map file below. If I leave it as shown below, with ...
1
vote
0answers
238 views
Moving GPS Points with a script - Bearing works well but distance is wrong
I am using a script I found online created in 2003 by one of the commentators here. It is a great script and exactly what I have been looking for and I'm very glad to have found it. It simply takes ...
0
votes
0answers
24 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
42 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
38 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
41 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
52 views
GMT raster (*.tiff + *.pgw) in epsg4326 shifts few kms (4326-900913-3857 problem?)
This seems to be an old problem with an already known solution (ie. "...stop using 900913 and start using 3857..."), but not sure whether this problem is about software versions, the raster itself or ...
0
votes
0answers
42 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
39 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 ...
