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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Tiled raster image to be placed in an OSM/ Leaflet.js map

I have a mapoverlay in a custom projection which I need to add as a layer to an open street map map within a website. Since I was not able to change the projection earlier, I decided to manipulate the ...
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2answers
578 views

Calculating bounding box coordinates based on center and radius

I need to calculate a bounding box for osm query. I get coordinates of center of the area (WGS84) and radius (meters). How can I do it? I though about using some kind of projection, calculating ...
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1answer
331 views

OpenLayers and custom Proj4 Projection

ok so I'm a newbee in using OpenLayers. I try to map some planetary data on my webMap server using OpenLayers. I defined a proj4 projection as follow: Proj4js.defs["MYDATUM"] = "+proj=longlat ...
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3 views

How to generate map tiles with TileStache and a custom projection

I would like to generate my own map tiles using TileStache and a custom projection. I have been struggling with this for quite some time and am hoping I can get some advice to get the tiles to ...
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2answers
44 views

Help projecting Austria data with QGIS

I'm trying to reproject this dataset from Austria Statistik Geodata. Data comes in "MGI_Austria_Lambert", and I'm trying to reproject to WGS84 What I'm doing is Saving layer as... and selecting ...
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735 views

What kinds of line segments/edges require high accuracy in a true surface-of-the-ellipsoid representation?

I've been musing (and doing prototype coding) for a 'projection free' geographic codebase with your basic point, line & polygon primitives. Rather than dealing with all the sacrifices that come ...
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12 views

A global, grid-like projection for creating heatmaps

I'm putting together an application where I need to create a vector grid which will be used to store and display a heatmap. It has the following requirements: Can cover the entire planet. The vast ...
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23 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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1answer
53 views

Changing map projection and adding graphic features in projected coordinate system using ArcGIS API for JavaScript?

I'm having some problems with the ArcGIS API for JavaScript. I have a web service that traces an electric network and sends back JSON with point and polyline (path) geometry. I've created a function ...
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OVERLAYING CURRENT INFO WITH PRIOR INFO OR INTEGRATING THEM ..hOMESTEAD RESTORATION pROJECT [closed]

WHAT SYSTEM OR APPLICATION TO USE FOR 3 OVERLAYS ON EXISTING MAP OF AN ADDRESS PURPOSE IS SHOW CURRENT SURFACE SLOPES OF A GROUND OR SURFACE LOCATION RESTORE WATERWAYS FOLLOWING NATURAL PATHS
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ArcGIS WGS84 Web Mercator Vs. WGS84 UTM zone 15N: Very different distance dimensions

I am working in ArgGIS 10.1 with a field (raster layer in tif format) in which I have placed two points (.shp layer). I have two versions of both layers, resulting four layers: one tif+shp set in CRS ...
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1answer
43 views

Pyproj: converting WGS84 to Robinson

I have a WGS84 coordinate pair (37.7749295, -122.4194155). I have an image that is a Robinson Map Projection of the world. I'm trying to write a python script to locate my WGS84 coordinate on my ...
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2answers
74 views

Google layers not matching

I'm working in a project with whole Europe data. I'm working with WGS84 (4326), and sometimes I overlay my polygons with Google maps layer (in QGIS) to see some details. When I do this, I have to ...
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1answer
80 views

Lambert Conformal Conic Projection Inverse Transform after Fitting Ellipse to Noisy LLA Data

I'm using Python and Basemaps to convert some Lat Lon data to the LCC projection and back again. Since it is noisy data representing the footprint of a satellite, I am filtering it and fitting an ...
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2answers
15k views

EPSG 3857 or 4326 for GoogleMaps, OpenStreetMap and Leaflet

The discussion at What is the difference between WGS84 and EPSG4326? shows that 4326 is just the EPSG identifier of WGS84.. Wikipedia entries for Google Maps and OpenStreetMap shows that they both ...
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1answer
143 views

using PostGIS to calculate distance of a route over a large area

I'm new to PostGIS and looking to measure the distance of the Pacific Crest Trail which spans western North America from Canada to Mexico. I have a data set containing the lat lon and dates from GPX ...
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6answers
13k views

Defining projections for multiple shapefiles in ArcMap?

I have over 100 shape files that don't have .prj file and thus when I bring them into ArcMap 10 they show the coordinate system as unknown. I know all of the shape files coordinate system is GCS WGS ...
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1answer
110 views

What are the pros and cons of forcing square pixels on reprojection?

I am using Erdas Imagine 2014 to reproject 4-band raster data from GRS 1980 NAD83 Lambert Conformal Conic (ft) to UTM GRS 1980 NAD83 North UTM Zone 11 (m). Unlike ArcGIS, Erdas provides the option to ...
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1answer
29 views

Unable to save to in Geojson format with the correct projection

I have a shape file (Polygon) in Qgis that I wish to save in Geojson in order to display it with the mapbox javascript api. Original projection is in POSGAR 97 My issue is that it does not reproject ...
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50 views

Cause of MODIS Reprojection Tool errors?

I have installed the MODIS Reprojection Tool (mrt) and it says the installation completed successfully but it does not mosaic my images properly. However, there seems to be some projection errors. ...
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24 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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1answer
172 views

Mercator bias plot in Leaflet

I was inspired by this wikipedia image from the mercator projections page to hack around with leaflet. The idea was to interactively have your cursor move a continent and that it would be corrected ...
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1answer
53 views

How do I convert Geo-Coordinates to Pixel-Coordinates on a Map?

I have an image file that is a Robinson Projection Map of the world. I have a list of geo-coordinates. I would like to find the pixel-coordinates on the map that correspond to my the geo-coordinates I ...
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12answers
28k views

What's the difference between a projection and a datum?

What's the difference between a projection and a datum?
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29 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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1answer
84 views

How to reproject from Clarke_1880_RGS_Lambert_Conformal_Conic to ETRS_1989_LAEA?

I am unable to reproject Marseille shapefiles from Clarke 1880 RGS_Lambert_Conformal_Conic to ETRS_1989_LAEA. I know that Clarke is a geographic coordinate system and it has no datum. I have tried ...
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1answer
332 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: ...
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1answer
414 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 ...
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1answer
61 views

Misaligned GADM shapefiles and the NE dataset

I am very new to using GIS programs, so please excuse me if this is a trivial question. I'm having the following problem: When adding a GADM shapefile layer for Uganda onto the Natural Earth set of ...
20
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4answers
14k views

Layers with same coordinate system should align/overlap but do not?

I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I ...
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2answers
400 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: ...
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1answer
24 views

Projecting INEGI shapefiles from Mexico - not lining up [duplicate]

I have two INEGI shapefiles from Mexico (2000 and 2010) that I want to line up with one another. The 2010 file projects in the right location and I would like the 2000 file to match/line up with the ...
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1answer
47 views

image rectification with Mercator projection

I have written an image rectification function which allows a user to select 2 points on an image and 2 points on a map. The function will then rectify the image so it is translated, scaled and ...
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1answer
50 views

How to find Latitudes and Longitudes of projections of the vertices of a rectangular plane below earth's surface? [closed]

I want to find out the latitudes and longitudes of projections of the vertices of a rectangular plane inside the earth's surface. I know dimensions of rectangle, angles of orientation and latitude and ...
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2answers
59 views

Accurate local map projections

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 ...
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2answers
369 views

GDAL/proj4 equirectangular projection coordinate system units assumed by OGRSpatialReference and GDALDataset::GetGeoTransform()?

How do I configure my OGRSpatialReference object to specify an equirectangular projection system http://en.wikipedia.org/wiki/Equirectangular_projection where the affine geo-transform matrix (provided ...
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1answer
19 views

6 degree to 3 degree Transverse Mercator transformation

I am looking to plot coordinates that were given to me but I am having some issues projections. I currently have my data projected to NAD83 MTM 1, but the coordinates that were given to me are based ...
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0answers
39 views

Difference between feature to raster and polygon to raster

(I'm using Arc 10.1) I'm trying to rasterize a data set. I have a shapefile with geographic coordinates (GCS_GDA_1994) which I want to convert to a raster with 100m grid cells. So I need to project ...
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1answer
40 views

Shapefile not projecting correctly [duplicate]

I am still new to this, so I apologise if I don't make a lot of sense! I am using QGIS 2.4.0 Chugiak. I am working on a project set to the GDA94/MGA Zone 50 coordinate system with 'on the fly ...
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1answer
27 views

Error reading large virtual raster with rasterio: “Cannot invert degenerate transform”

I've created a virtual raster using gdalbuildvrt, which covers a large extent (England) at a high resolution. The data is fairly sparse, focused around the coastlines with no files covering inland ...
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3answers
2k views

How to convert projection

I got sample shape files with the following *prj file content: ...
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1answer
187 views

Projection to use with satellite image from Google Maps / Earth

I'm very new to anything concerning GIS so please forgive me if this question has been asked before, but I assure you, I've been trying to find an answer for quite some time now. Of course it is ...
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0answers
39 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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1answer
117 views

Trying to set NAD 1983 EPSG 102631 in QGIS

I was able to find the right coordinate system online NAD 1983 Alaska But now I don't know what to do. I can't find the coordinate system on QGIS. When I choose the one I think is correct it warps ...
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40 views

Understanding X Y coordinates: geocode before or after projecting? What determines how many decimal places?

I am trying to figure out how different my groups' past Network Analyst analyses have been because they were using a geographic instead of projected coordinate system. But I'm getting hung up on the X ...
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1answer
20 views

Figuring out what coordinates supposedly using 'NAD31 projection' refer to

I'm working with a GeoJSON file that contains sets of coordinates associated with street corners in the city of Montreal, Canada. The spec sheet of the API delivering those GeoJSON specifies that the ...
2
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1answer
49 views

Why is this .prj file causing the shapefile to render in meters instead degrees?

So I've got a shapefile that has polygons of countries, with coordinates in decimal degrees: Country (String) = Algeria POLYGON ((6.928073999999953 36.88360652, 6.949973999999969 ...
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1answer
125 views

How to find the projection of an image?

Instead of georeferencing the image and deforming it, I'm trying to find the projection used by the author of the image. I've got tens of these distribution maps to digitize. The idea is to avoid ...
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1answer
30 views

Determining projection of Texas county shapefile?

I have a Shapefile of San Jacinto County in Texas. It thinks it is NAD83 UTM Zone 15N, but the dataset isn't jiving with any other dataset. Max X: 1,073,721 Max Y: 11,223,970 Min X: 895,728 ...
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19 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 ...