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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138 views

How do you clip a gnomonic or stereographic azimuthal projection?

I have polygons comprised of lat/lon coordinates and I want to project them onto a plane that's appropriate for polygon operations (such as checking for intersections). In some cases, the polygons ...
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255 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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67 views

Is it safe to store coordinates on NFC tags always in one CRS and rely on conversion for others

I'm involved in NFC (Near Field Communication) standardization of a record structure for geographic point locations. That will allow to put coordinates on NFC memory tags which can be read with a ...
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167 views

How can I improve the resolution of a vector grid made in north pole stereographic projection?

I've been struggling with this for a while and wondered if someone could lend a hand. I have a map which already has sampling points from centroids in a 35x35km grid that was created in north pole ...
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38 views

Differences between points and lines as poles in an equal area projection

I am planning on using an equal area projection in a current project. I used this website to determine which projection I should be using. I hadn't previously considered it, and was wondering if ...
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2k views

How do I change from lat/long to a metric coordinate system in GRASS?

Yes, it's yet another transformation question. I am working with ASTER DEM data, which is LatLong WGS84. I want to process the DEM map into an STL file for use in a CFD simulation. The script I am ...
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1k views

Projecting a Raster from WGS84 to planar Equal Area to Calculate Area: How to Select the Cell Size?

I have a broad question on how to calculate the 'correct' cell size for a raster when analyzing an area not at the equator. My goal is to project a land cover raster provided in GCS WGS84 to an equal ...
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225 views

Mercator projection that shrinks toward pole

I've noticed that lots of map viewer (especially those nautical chart viewer) will shrink a mercator projected chart while panning towards poles. Is this some compensation for mercator distortion? ...
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416 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_ ...
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225 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 = ...
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150 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 ...
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96 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) ...
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244 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 ...
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109 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 ...
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649 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 ...
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20 views

Which SQL Server spatial data type to use for UK data in SQL Server?

Which spatial data type should be used for UK data in SQL Server?, i.e. GEOMETRY or GEOGRAPHY? I'm aware of OS National Grid and my understanding is it's an X/Y coordinate system, covering from ...
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9 views

Openlayers Reprojection from 4326 to 3395 is wrong?

I'm using proj4js definitions downloaded directly from epsg.io webpage. When trying to reproject a small extent I get this result: ol.proj.transformExtent([-180, -90, -179, -89], 'EPSG:4326', ...
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27 views

PostGIS Svg Projection on Google Map

Context I have a database with spatial data such as areas and points. Some of the areas in my db are coming from OpenStreetMaps, representing some regions. (Which are kinda small at earth's scale, ...
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38 views

Is there any way to use Cesiumjs to import 3D Models using the British National Grid (OSGB36)?

I am trying to import a 3D model (.gltf) into Cesium which is in OSGB36 projection, however I know that Cesiumjs doesn't support British projection natively. I've tried changing the origin of the ...
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31 views

Gdalwarp UTM reprojection causes image distortions

I'm trying to re-project Sentinel-2 images to a common UTM zone in order to create a mosaic. For this I'm using gdalwarp with the following syntax: C:/OSGeo4W64/OSGeo4W.bat; gdalwarp -t_srs ...
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34 views

Need to match the Coordinate system on vector and raster datasets

I have a google satellite image that I am using as my basemap. The problem is that the shp files that I got from some source are projected in WGS 1984 UTM, Zone 42 North, Meter, but its GCS is ...
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17 views

Create points with planar location data

Slightly confused. I need to add 3 point features to an already created map project (state plane projection). The description given to me about the location of the points is the planar location, so no ...
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32 views

Issue on project CRS loading a georeferenced image

I have a georeferenced image in EPSG 26714. When I load it in Qgis 2.14 the project CRS is set to 4326. I asked for the layer properties and the CRS registered is 26714. When I open the same file in ...
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22 views

Unknown coordinate system produced in 1980 by Japanese company in North Philippines

I am having the same difficulty with one of the report produced in 1980 by Japanese company. The grids format also N 38,578, E 41,400. The project is 390 kilometers north of Manila. I would like to ...
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19 views

Raster and digitized shapefile misplaced in same projection

I have georeferenced .tiff rasters with cadastral borders and corresponding digitized borders in shapefile based on that raster. All that was done in some Mapsoft software. When I insert both in QGIS ...
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32 views

Where can I download a world shapefile with 180-degree central meridian?

Does anyone know where I could download a world shapefile that has a projection with a central meridian of 180 degrees longitude? I have found the following question that provides instructions for ...
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45 views

Formula for Nicolosi Globular Projection

What is the formula for the Nicolosi Globular projection? In other words, what is the function that maps the coordinate (φ, λ) on the sphere to the coordinate (x, y) on the plane? You can assume ...
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53 views

Determining printed map projection?

A friend of mine is working on a small project to map receding North Pole summer sea ice minimums by decadal averages on a wall-paper map. Unfortunately, it seems as though the map projection for ...
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68 views

Geographic vs. projected raster cell size area

I am wondering the best way of knowing how to define the area of each raster cell in global data. Specifically, I downloaded all ~400 tiles of MODIS land cover data, mosaiced them into one, and now am ...
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39 views

Correcting for offset

I have a shape file with RTK measurements as a line feature, which more or less corresponds with visible features in a raster layer (shaped as lines). These measurements however are not accurate ...
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32 views

connecting ecw to its projection and grid data in an xml file

I'm new to mapping please go easy on me:) I have a bunch of ecw files with 2 xml file one is a file ending with *.ecw.xml and one with *.ecw.aux.xml I am trying to load the ecw files into ...
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22 views

Converting Grid to Geographic?

My project specifications are as below: utilise geodetic and shift parameters between WGS84 and specified datum (ED50), local projection (UTM 31N, CM 3 East) and transformation (EPSG1613) for all ...
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51 views

Projection Issues - OpenLayers / MapServer / NAD83 State Plane FT

I am having projection issues with OpenLayers version 2.13 with MapServer and the Proj4 library. Pulling layers in NAD83 State Plane Feet projections on top of an OSM or MapQuest Base Map in Google ...
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38 views

Converting coordinate obtained from google maps to be used with gdal_translate in java or cs2cs?

this is a follow on question from Geo-Referencing an image from google maps with gdal_translate I am trying to get cs2cs to work but I am getting the following error. My command is as follows: ...
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34 views

getting started designing satellite projection raster

How do I get started designing a map with a satellite projection like this:http://bl.ocks.org/joyrexus/6619251. So far using d3 I've created a map of North Africa w/ topojson and tiles from Mapbox but ...
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50 views

d3.js Projection for Washington DC area

I'm making a small thematic map of the Washington DC area using d3.js. Everything I've tried "tilts" the square of DC. Is there a d3 projection that will put DC at the right angle? ...
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61 views

Getting same results from Mapping toolbox of MATLAB as ArcMap?

I am newbie in GEO. I have a point [lat,lon] = [-77.5100 , 166.4000]. I want to find its projection based on equidistant Azimuthal projection method. When I use ArcMap 10.3.1 (with default ...
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147 views

Transforming zonal and meridional velocity from regular lat lon to rotated lat lon?

Like in Transforming regular lat/lon to rotated lat/lon? that was asked before, I am working with climate data and I need to transform zonal and meridional velocities (u and v) from regular lat lon ...
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39 views

Creating equirectangular projection from 3d spatial model?

Apologies if this is not the right group for this question, but I think there may be people here who can help. (I'm open to suggestions for better places to ask.) I have a program that contains a ...
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42 views

Correctness of Measurement

I tried Google, but the questions isn't that easy to put in Google, so I haven't found anything about this. I am making a database with different locations (latitude and longitude). For this I have ...
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27 views

Measuring large distances when all layers are in decimal degrees using QGIS?

I just developed a distance matrix between various points across Canada in QGIS. The distances produced are in decimal degrees, and I would like to view them in metric. I am unsure how to do this.
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84 views

gdalwarp UTM Zone 1 to WGS84 - fails to transform

I have a global dataset consisting of tiles in UTM projection that I want to mosaic and therefore need to reproject to a common projection. Can I solve my reprojection error with options to gdalwarp ...
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0answers
71 views

How to align with QGIS two layers that have the same projection?

I am using QGIS 2.12.0 to create forest maps. I usually succeed to create maps from shapefiles with different projections but for some reason I cannot succeed to align the layer of one shapefile. As ...
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44 views

how to fix projection in QGIS from earth data

After downloading and opening natural earth data in QGIS, the result shows like this I have tried uncheck simplify geometry but it doesn’t work. I think the problem is related with globe ...
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28 views

Raster statistics change after re-projection — which one is correct

I'm looking into some global DEMs (like ETOPO1 - http://www.ngdc.noaa.gov/mgg/global/global.html), and noticed that the statistics for the elevation values can change quite a bit after reprojecting ...
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31 views

Openlayers GeoJSON write not maintaining projections

How do I get GeoJSON.write to maintain the projections used in the construction of the GeoJSON? points.geojson {   "type": "FeatureCollection",   "features": [     {       "type": "Feature",       ...
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53 views

QGIS Server & custom CRS

I'm using QGIS Server and an OpenLayers-based web client (in EPSG:3857). I have a QGIS project that I want to serve with QGIS Server, containing layers in several CRS, including custom ones. ...
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21 views

Geoserver import does not recognize projection

Using GeoServer 2.8 and the Data importer plugin I can import shapefiles generated in ArcMap with WGS84 geographic coordinates (EPSG:4326) and UTM+WGS84 projection (epsg:32724). As a reminder, ArcMAP ...
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97 views

How to test polar stereographic projection for a specific longitude intersection?

I'm writing a library that tests grids defined by map projections for intersections, and am running into an issue implementing the test for polar stereographic and rectangular projections - ...
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22 views

Should I set the projection if the data has already been projected?

I need to plot some data which was produced on a native grid with a lambert conformal conic projection. I need to create a geotiff (using python and gdal) and was wondering how to go about and do ...