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Questions tagged [map-projections]

A map-projection transforms the coordinates of the spherical earth to a flat map in cartesian (x,y) space.

A map-projection transforms the coordinates of the spherical earth, usually given in degrees (latitude, longitude), to a flat cartesian (x,y) space.
There is no perfect projection, it can be proved that each projection has a drawback, one have minor others major ones.

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How to change a Lambert Conic Conformal raster projection to latlon degree R

I have a raster, obtained from a netcdf which is in (Lambert Conic Conformal projection): library(meteoForecast) wrf_temporary <- getRaster("temp", day = Sys.Date(), frames = 'complete', resolution = 36, service = "meteogalicia") …
Ricardo Faria
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Azimuthal Equidistant projection anomalies

When projecting to the Azimuthal Equidistant projection in R's rgdal the results seem strange. Take this example: require(rgdal) require(maptools) data(wrld_simpl) azim_polar = '+proj=aeqd +lat_0=90 +lon_0=0' azim_orign = '+proj=aeqd +lat_0=0…
geotheory
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Python nearest neighbour - coordinates

I wanted to check I was using scipy's KD tree correctly because it appears slower than a simple bruteforce. I had three questions regarding this: Q1. If I create the following test data: nplen = 1000000 # WGS84 lat/long point = [51.349,-0.19] # This…
mptevsion
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Python basemap - read shapefile given in map projection coordinates

I am trying to read a shapefile of San Francisco Police Departments (https://data.sfgov.org/Public-Safety/SFPD-Districts-Zipped-Shapefile-Format-/8yyx-6uur) via basemap. When i use the basemap.readshapefile method, I get the error shapefile must…
farnold
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Raster image seems to be shifted using leaflet for R

I want to plot some spatial data using the leaflet package in R, however the generated raster image seems to be shifted compared to a reference grid. I suspect map projection issue, but I am not expert on the topic, so any help would be…
rozsasarpi
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Using LINQ to map dynamically (or construct projections)

I know I can map two object types with LINQ using a projection as so: var destModel = from m in sourceModel select new DestModelType {A = m.A, C = m.C, E = m.E} where class SourceModelType { string A {get; set;} string B…
CodeGrue
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How to work OSMDroid with Web Map Service (WMS) used by the private provider?

I'm trying to put the OSMDroid to work with WMS, but I do not find a way to put the WMS working. Objective: OSMDroid working with WMS (projection EPSG:4326) Tentative: I followed this example and include files: WMSMapTileProviderBasic,…
Johnitro
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How to convert UTM to Lat/Long?

Is there a way to convert UTM to Lat/Long in Javascript? I have seen another thread on this but it was in Java and Python which won't help me much. Please let me know, thanks.
Josh
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Convert Lat/Longs to X/Y Coordinates on Albers projection map

I have a map with Albers projection and i have Lat and Long of some location and i need to draw a point on this image. I know that this map was built with Albers projection using standard parallels on 52 and 64 and WGS 84. I tryed to implement…
PePe
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how to snip or crop or white-fill a rectangle tightly surrounding the outside of a polygon with ggplot2

I'm just trying to white-fill the area outside of a simple polygon. For some reason, it's screwing up by drawing a weird stake through the center like it thinks its a vampire slayer or something. I tried following this post but something's gone…
Anthony Damico
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How can I add a lat-long grid to a projected map?

EDIT: question really pertains to how one can add lat/long gridlines to a projected map. I changed title to match. I have some layers in geographic coords. I want to plot them in LCC projection, but have a geographic (lat/long) grid. From mapproj I…
a different ben
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How to use Google Maps projection with GeoDjango/PostGIS

I am building a web service with GeoDjango which involves user submitted events including a location. I created a model field for my location using django.contrib.gis.db: location = models.PointField(srid=900913) I chose to specify 900913 as I…
Ferguzz
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Mapping lat/lon coordinates to a bitmap image of a map, not fixed to one projection

I'm currently developing a small piece of (Java) software that should be able to display maps and the current GPS position within that map. I'm absolutely new to this, but it is pretty obvious that I'll have to do some kind of coordinate…
Jens
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Convert Latitude / Longitude to relative X / Y coordinates on a georeferenced map

On a map that I know the coordinates (lat/lng) of three corners (or any three non aligned points) I have coordinates (lat/lng) of a few points that are located on the map. What I want is the relative coordinates (x/y relative to top left corner) of…
luxcem
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Google Maps ImageMapTypeOptions.getTileUrl convert point and zoom to LatLng

In google maps v3 api, How do I convert the point and zoom that get passed to ImageMapTypeOptions.getTitleUrl to a LatLng? Thanks!
Drew LeSueur
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