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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Overlaying layers with different projections on Android

Hello, I'm trying to show a map on Android. I'm using two map providers and am having trouble when converting geo point(lat/lon) to point in my viewport(x/y in pixels). 1) the first map provider used ...
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1answer
716 views

How to generate a grid of horizontal equal-area rectangles in a Mercator projection?

I'm new to GIS so pardon my ignorance and bear with me. I'm generating a grid relative to a LonLat point. To make the cells all equal area, I'm creating it in 2163 projection. The problem is that when ...
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2answers
1k views

Setting the map projection in the flex API to an overlay layer

I'd like to use a basemap containing world map data as a backdrop to some point and outline data that I'm hosting in ArcGIS server in the ESRI Flex API, but I would like the map control to share a ...
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1answer
1k views

Conversion of any projection to latlong using proj4 string

I am using a tool which uses proj4 lib to project maps. I have a set of xy coordinates to be converted to latlongs with that tool. as I have the source projection string say +proj=aea +datum=NAD83 ...
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1answer
21 views

Strange Custom Projection can't be transformed

I've got a a database of feature classes that were somehow transformed into a custom projection that I don't understand, and there does not seem to be a way to get back out of. The projection data ...
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1answer
38 views

Projection issue with WMTS in QGIS?

I'm trying to connect to this WMTS in QGIS, but I'm having issues that I think are projection related. I use the Add WMS/WMTS dialog and enter this url: ...
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1answer
22 views

Given WGS84 bounding box, is there service that returns most accurate projection to use?

I'd like to find a service to convert lat/lon in WGS84 to an arbitrary coordinate system in metric that will be the most accurate for my bounding box. Does something like this exist? For instance, ...
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1answer
54 views

Way to Shrink Alaska and Hawaii for “Stereotypical View”

Is there anyway to shrink Alaska and Hawaii to create a map that looks like the stereotypical map with AK in the corner, etc.? I thought about trying to isolate AK and HI in their own layers and then ...
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53 views

Alaska Series E projection in ArcGIS for Desktop?

I am trying to digitize a scanned map that appears to be in the Alaska Series E projection. I have also seen this referred to as Modified Transverse Mercator. While this projection is listed as ...
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1answer
105 views

What projection to use to get a game map into QGIS?

I have built and maintain a SWTOR game map atlas. At the moment, it's all static jpg maps, but I would like to get the info into an actual GIS software to get more functionality and make my website ...
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1answer
213 views

Defining projection using readOGR if the shapefile doesn't have it?

I think that by using readOGR to import a shapefile renders worthless to put proj4string to the script since if any coords are available in the shapefile, it will be transported through the readOGR. ...
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1answer
204 views

How to plot a full hemispheric orthographic projection in R

I want to make a plot like that using R: All I want is the country borders as seen from outer space, no fancy colors needed. It seems I need to use the spTransform function, but it gives me a "non ...
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1answer
233 views

Reprojecting MODIS Ice Sea Temperature products with gdalwarp

I have problems projecting MODIS Ice Sea Temperature (IST) products to EPSG:3031 (Antartic Polar Stereographic) using gdalwarp. The product I'm working with is MOD29E1D, documented here, p33: The ...
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2answers
517 views

How to use PROJ4 to reproject a file

Unfortunately, GDAL does not support a particular projection I am trying to achieve (the ob_tran rotated pole projection), so I am trying to use PROJ4 to convert a geotiff file to the projection I ...
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2answers
938 views

QGIS DXF file projection match

I need to use this file on a map but I am not able to match the projection with the others I have, primarily data downloaded from OSM (city of Boston). I read many articles, I have repeatedly tried to ...
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377 views

in python, srs.ExportToProj4() returns an empty string, why?

I have a shapefile with the following .prj file: ...
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1answer
211 views

What are the set of projections that can be accurately georeferenced using polynomial 2?

Background I'm starting with a map from the internet (Encyclopedia Britannica) and georeferencing it using QGIS 2.0.1, I get really accurate georeference solution using polynomial 2 transformation: ...
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381 views

Calculate distance in QGIS, wrong geographic projection?

I'm trying to do the following: I have 2 shapefiles, one containing all the public schools in NY, another one containing the hotspots in NY (both in points form). Now what I'm trying to do is ...
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1answer
49 views

Does IDistanceOP.EucDistanceFull require a projected coordinate system?

I have designed an implementation of ArcObjects' IDistanceOP.EucDistanceFull. It takes its input as a feature class and converts it to a GeoDataset with which EucDistanceFull can work with. It works ...
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2answers
7k views

What are the units of the calculated area from a raster in decimal degree

I'm trying to calculate area for a raster file which contains 2 layers (0 for unsuitable habitat and 1 for suitable). It's been calculated successfully but I don't know what is the unit of the ...
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1answer
891 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) ...
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2answers
741 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? ...
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1answer
168 views

CRS Austrian Lambert/WGS84

I am totally new to Qgis (or GIS in total): My problem is to get two layers in same CRS to do an intersection and further analysis described in the blog of underdark (Groupstat tutorial). My is the ...
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1answer
469 views

USGS GeoTiff extent via GDAL

I have 2006 land cover GeoTiff from the USGS site (for a county in VA, USA). The projection is Albers Conical Equal Area Units. The download came with an HTML metadata file that tells me the geo ...
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435 views

Question Regarding Interpretation of Openlayers BBOX in 4326 Projection

I have a BBOX strategy in my Vector layer, which is sending HTTP GET Requests to my server in order to get the features I wish to display. The projection of the layer is EPSG:4326, so it is my ...
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2answers
231 views

Converting lat lon into co-ordinates (in ft of m)

I have a set of latitude and longitude of a series of points which specific the trajectory of a vehicle. If I consider the first point as the origin (0,0), is it possible to convert the trajectory ...
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1answer
398 views

Problem in displaying a GeoTiff image in JMapFrame

I'm trying to display a GeoTiff image with no projection but where the geographical extent (bounding box) is known: reader= format.getReader(new File(sImageName)); GridCoverage2D gridCoverage= ...
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1answer
809 views

Calculate bounding box + buffer for rendering a map tile with mapnik library

Mapnik library has a Projection object (I'm using Python bindings): spherical_mercator = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null ...
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1answer
392 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 ...
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22 views

Rectangle shapefiles with the same extents does not align perfectly after projection

I have a rectangle shapefile built with UTM19 coordinates using a python script, and then projected to NAD83_CSRS (EPSG:4617). I have a second rectangle shapefile built with the same method (python ...
3
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1answer
42 views

Coordinate points not lining up with a preexisting map on QGIS

I asked this question once before, but I did not receive any feedback on solving on the issue and I am still confused as to what I am doing wrong. I found a public domain map of Florida counties on ...
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37 views

GDAL c# API returned different WKT from gdalinfo

I've found completely different results in WKT strings while using gdalinfo utility and method from c# API GetProjectionRef(). In the first case the result was: PROJCS["WGS 84 / Pseudo-Mercator", ...
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1answer
45 views

Vincenty or (Project + Euclidean) for accurate distances

I posted a similar question on stackoverflow, however was directed here for more help. If my main goal was to calculate distances such that my error was minimised to the nearest metre assuming that ...
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66 views

How to calculate false easting/northing for Lambert Conformal Conic projection

I'm defining a new GRASS location using the Lambert Conformal Conic projection. My understanding is that the values for the standard parallels and central meridian are dependent on my area of ...
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0answers
48 views

Transforming lat and long to Mercator x and y

I've been trying to plot a set of lat and long coordinates to a Mercator map using the following set of equations; x = long - long0 y = ln(tan(pi/4 + lat/2)) These equations are from a page on ...
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41 views

Choosing projection for routes that fall within two UTM zones? [duplicate]

I'm creating charts for routes that fall within two UTM zones; 30S and 31S. The offshore routes are in the Alboran / Balearic Sea - connecting Spain to Algeria. What projection should I use?
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52 views

Wrong area using Albers Equal Area Projection in GRASS for Java, Indonesia

I am just getting to know GRASS 7.0 and I am struggling finding a good projection to work on a spatial analysis of Java, Indonesia. I am new to the forum, so if information's are missing for a better ...
3
votes
1answer
21 views

GCS and PCS data misalignment in ArcMap when zoomed in

I have a shapefile in NAD83 UTM18 which I need to get into GCS NAD83. I tried both loading it into an empty GCS NAD83 feature class directly and the "project" tool. The results are the same - the ...
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50 views

Do locations “move” when shifting datum?

I hope that this is the right Stack Exchange for this question. I may be oversimplifying this, but I'm looking for verification in my understanding of the following: If I have a spatial dataset in 2 ...
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97 views

Which projection can I use to see alignments on great circles?

I want to put on a QGIS map some historical sites to check if they are aligned. If an alignement exists, the points should stay on a great circle (is this correct?). I want to visually verify this ...
3
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0answers
310 views

Align vector and raster layers with D3

I have a geocoded raster image that I want to use as the background to a vector map with D3.js. The screenshot shows the layers in QGIS (grey is raster). Here's the markup for the map: <div ...
3
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0answers
76 views

Finding centroids for icosahedral gnomonic projection?

I've been trying to create an icosahedral gnomonic projection, like this example by Jason Davies or this one (the Fisher projection). The method that I initially used was using the centroid of each ...
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293 views

Why does field calculator compute area in square meters?

I am using EPSG:102748, and have set my Settings/Option preferred measurement units to ft. My CRS is NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet, and when I use the measure tool, it returns ...
3
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0answers
200 views

Is there a way to expose Spherical Mercator Lat Lon in Google Map API?

The map tiles in the Google Maps are in Spherical Mercator projection (srid 900913), but in the API the methods report coordinates in Lat/Lon WGS84, e.g. map.getCenter(). Is there a way to return the ...
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343 views

Formula for maximum coverage of a geostationary satellite based on earth station elevation

I am trying to create a javascript function to represent the maximum coverage of a geo satellite for different antenna elevations (0 degrees, 5 and 10 degrees) with 3 leaflet polylines. The result is ...
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71 views

Distortion in projected raster

I am having a frustrating problem with something that I think should be very simple. I have a number of DEMs from the National Elevation Dataset (NED), that come standard in the NAD83 coordinate ...
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729 views

Difference between feature to raster and polygon to raster [duplicate]

(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 ...
3
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85 views

Is it possible to render tile-based web mapping projects in any other projection than web mercator?

Web-mapping technology has to a large degree adopted the web-mercator projection as the standard projection for displaying geographic objects with interactive map-clients. This is due to many factors ...
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828 views

Fortifying re-projected shapefile for ggplot2 in R

I have a shapefile of US county boundaries which I got from the NHGIS. I can load the file using the rgdal package and see information about it: library(rgdal) shp_1860 <- readOGR("shp", ...
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2answers
587 views

Partial Map Pixel Projections

I have the following: A PNG or JPG of a random width and height, in pixels, that represents a partial map of the world (i.e. a rectangle of the United States). The four corners of this image are ...