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

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Spherical Mercator - World bounds

What are the correct world bounds in the Spherical Mercator projection (EPSG:3857 and EPSG:900913) In some source I got those bounds see this link in the maxExtent parameter: minx: -20037508.3427892 ...
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130 views

How does OpenLayers 3 handle coordinates?

Ol3 always uses the flatCoordinates because obviously it needs 2d-coordinates as the screen is only 2-dimensional. But how does OL3 calculate the flat representation? For example if my view’s ...
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46 views

set Default projection in postgis table

I've set the SRID 4326 for a table having geometry column, but when i insert a geometry without SRID, i get an error because no SRID specified is interpreted as -1 or 0, so how i can set a default ...
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38 views

Zonal geometry output in ArcGIS

Is there a way to specify the coordinate type in Zonal geometry output in ArcGIS? I am trying to perform zonal geometry on a raster and in the resulting output, the XCENTROID and YCENTROID are in ...
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49 views

ESRI/Mapinfo MGA56 prj vs QGIS MGA56 prj

I am trying to understand why the degree unit is different between ESRI/Mapinfo and QGIS: ESRI/Mapinfo ...
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67 views

Raster overlay with different projection in Google Maps

I have a map created with Google Maps. I want to overlay over some data I am downloading dynamically, covering the whole world. That data is a matrix as follows: 1024 values for the longitude ...
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50 views

Which projection should be chosen to model transmission lines across the USA?

I am looking at different options for high voltage power lines in the US. These power lines cross several states. Since in the end the distance is of importance, is the USA Contiguous Equidistant ...
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22 views

Changing Area Output - PUMAS

I currently have shapefile of US PUMAS and another feature shape file (call it feature X). I am using arcpy to project both of these files to the following projection coordinate system (using ...
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20 views

QGIS - Label polygon with different projections

I have a polygon layer projected in an UTM. In properties I checked 'show all labels for this layer'. Does anyone know why the label does not show until zoom 15:1 in QGIS with CRS-4326, while in ...
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59 views

Unknown coordinates in Shapefile, projecting doesn't give expected results

I'm reading a Shape file (four files actually, .dbf, .prj, .shp and .shx) containing polygons representing certain areas in my neighborhood. For this I use C# and a library called DotSpatial. I can ...
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152 views

Length difference between Google Earth and ArcGIS for Desktop?

I have drawn a complex path with multiple vertices in Google Earth (GE) Pro and its measurement property is shown as being 2,460 nm. It is located East of Australia. If i import this KML into ArcGIS ...
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30 views

Resampling methodology when projecting a raster

When projecting an SRTM raster with "Project Raster" tool in ArcGIS10.2, what is the best resampling methodology, bilinear ot cubic convolution?
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30 views

QGIS (2.0.1): Field calculator for length not working - values way too high

Same problem as another thread: Field Calculator returning incorrect length and area values Trying to calculate length of a line shapefile, and field calculator is returning values that are way too ...
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148 views

Show a kml (which uses longitude and latitude EPSG:4326) in “google/OSM” projection (EPSG:3857) in open street map

I am showing a kml layer, over OSM. The points in the kml are latitude/longitude (EPSG:4326). I don't have to convert any points or anything, it all just works. Great! Now, the client also wants to ...
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116 views

Projection problems when importing .kml from Google Earth to QGIS

I want to open several points that I exported from Google Earth as a .kml in QGIS for further use. I can import the data and the points are displayed but something must be wrong with the projection as ...
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53 views

How i can have the same xMin,yMin for vector files in Qgis 2.4

i have a .shp file(polygon) in EPSG:2100 - GGRS87 / Greek Grid and an other .shp(points) in the same system(EPSG:2100 - GGRS87 ) but different xMin,yMin. The first has xMin,yMin 583309.00,4152885.94 ...
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222 views

How to prevent cross-world lines in ggplot world map?

I'm having issues displaying 'great circles' paths and polygons in ggmap, an extension of ggplot2. Please enter the following code to replicate my issues: ...
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44 views

Can I get Geoserver to return a WMS in gnomonic projection?

I need to be able to pass in the center lat and long. I have tried using the AUTO Namespace for SRS (which works) but this only supports a few projections, the closest being orthographic. I have ...
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72 views

Appropriate reference system for small-scale mapping of the Middle East

I want to create a thematic map of the Middle East that displays certain historic places and regions on a small-scale map (between 1:6.000.0000 and 1:12.000.000). The map has to center the boundary ...
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83 views

Clustering the WGS84 point features (projection transformation aspects)

My question is quite trivial and was discussed many times before (like here) but in our case it has the confounding extra requirements... The list of sparsely distributed 2d point features is stored ...
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30 views

Projecting Data with Transformations - Alignment Issue

Problem: I am having problems getting data to align properly with basemaps layers. The image below shows the difference between roads. The centerlines shapefile's coordinate system is ...
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611 views

How to overlay a flat image onto google maps with two points of reference?

The Android API allows for images to be superimposed onto a map. To do so, the developer specifies a set of lat/long coordinates for an "anchor point" within the image, the width (or height) of the ...
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97 views

Arcmap: transform an image from Web Mercator Projection to Simple Cylindrical (Plate Carree) projection

I have an image that is projected using the Web Mercator projection. Does anybody know how to transform (in Arcmap) this image from the Web Mercator projection to the Simple Cylindrical (Plate Carree) ...
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54 views

Vector seems to be only a pixel of a raster after reprojection

I have the South America hydro1k data for slopes and I am trying to extract the data using point sampling tool with a grid in Brazil's map. My problem is that, even though vector and raster seem to ...
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144 views

Google Map Projection Skew - Need correct Projection

I'm having a really difficult time resolving skewed grids when projecting onto Google maps using Alteryx outputs. Within the module, I'm taking GRD files and aggregating rows and columns to re-size ...
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61 views

Question about projected coordinate systems 30m DEM for Contiguous US

What is the best Projected Coordinate System (PCS) for the contiguous US (whole, not parts) if I want to maintain distance and area accuracy as much as possible across a nationwide DEM dataset? I'm ...
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94 views

Why can't I reproject from HARN State Plane Ft Intl to State Plane Ft?

I'm attempting to reproject a feature class that is: NAD_1983_HARN_StatePlane_Oregon_North_FIPS_3601_Feet_Intl to our standard, which is: NAD_1983_StatePlane_Oregon_North_FIPS_3601_Feet When I ...
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96 views

Geodjango transform introduces large errors

Apologies for the possibly naive question. I'm trying to understand how Geodjango (running on PostGIS) deals with coordinate transformations, and am experiencing some unusual behaviour. Let's say I ...
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201 views

MySQL+GDal+MapServer+OpenLayers WebMercator problem

I have a problem/question what is the most efficiant way to go from WGS84 (epsg:4326) to webmercator. Outline of the structure right now: MySQL Database: with point Latitude/Lontiude Data [~200 ...
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207 views

Conversion problem of projection of MODIS LAI from sinusoidal to geographic

I am trying to change MODIS data's (LAI) sinusoidal projection to geographic. Actually I did it. But when I reproject it by ERDAS, the output LAI raster moved about 10 km to west side of actual shape ...
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171 views

Calculating closest distances in meters/kilometers given lat/long coordinates?

I am using ArcGIS 10.2 for Desktop. I have a shape file containing points worldwide with lat and long, and another world map polygon file whose Geographic Coordinate System is GCS_WGS_1984 and Datum ...
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133 views

LiDAR dataset displaying 500 meters to the east of correct position

Why does my LIDAR dataset show up ~500 meters to the east of the correct position even though a spatial reference/coordinate system is provided? Some background: The LIDAR data were downloaded from ...
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43 views

Add a raster specifying the projection in pyqgis

I would like add an raster but I want to specify the projection. If I do : qgis.utils.iface.addRasterLayer(url,layerName) QGIS ask me to specify the projection. I want to this with python. How I ...
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182 views

Kartograph - “projection not named”

The Kartograph package looks very promising, so I have been trying play around with it. As it turns out, I have been able to get the most basic map to work (the "world.json" example), but I could not ...
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96 views

How can I obtain the unit of a projection SRID?

Given a projection SRID, is there a way I can obtain the coordinates unit string (meter, degree, ...) ? In PostGIS for example, it looks like it is present in the srtext column of spatial_ref_sys. ...
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285 views

Incorrect coordinates when reprojecting NAD27 to NAD83

I have some historic UTM coordinates as NAD27 (556787, 7169250) which I entered into a spreadsheet and have imported into QGIS. I assign them the projection Nad27 / UTM zone 12N (EPSG: 26712) I ...
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149 views

Am I correctly projecting a geometry using a WKID in ArcObjects?

I would like to take in any valid WKID for a spatial reference and then project a single geometry to it. The following code seems to be working, but (1.) can someone verify that this is the correct ...
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474 views

Help me convert this US Lambert Conformal Conic Google Maps Projection to Australia

Following on from this question: Identify what projection this Australian map uses? <- this is the sort of map i want to load in I need help changing the bits necessary in this example of Lambert ...
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50 views

CRS centered on the 180 meridian?

The problem I'm dealing with is the old 180 meridian problem, except I'm not trying to plot or render shapes that cross it, I need to do intersections of lines that cross it. The only spherical ...
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50 views

Create oblique projection?

bit of an odd one which isn't necessarily package-specific. I'm trying to make a tshirt with a map section centred on the plane between San Francisco, USA, to Galway, Ireland. The Great Circle line ...
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402 views

Reprojecting GeoTIFFs to WGS84/UTM

I'm using libgeotiff and proj4 to read and (try to!) process GeoTIFFs. After reading the file, I want to get the corner coordinates in WGS84/UTM - but there are so many functions and parameters to try ...
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156 views

Trying to convert to EPSG:27700 (Ordnance Survey) projection, unable to do so

I'm trying to code an interface that allows a user to draw a vector shape on openstreetmap, which is then converted to a WKT string, processed by the server and sent of as a WFS query to emapsite ...
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727 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: ...
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61 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 = ...
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275 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 ...
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148 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 ...
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96 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 ...
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73 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 ...
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577 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,
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139 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 ...