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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61 views

How to create an interrupted Mollweide map in R?

I am wondering if it is possible to create an interrupted Mollweide map in R. This question is similar to Discontinuous or Interrupted map projections? which does not really have a satisfactory ...
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1answer
75 views

Calculating Grid Convergence for Lambert Conformal Conic

What is the formula to calculate Grid Convergence angle (angle between true north and grid north) for Lambert Conformal Conic projection for a given location. Searching online, I have been able to ...
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1answer
95 views

Georeferencing a raster using GDAL and Python

I want to georeference a raster using python and GDAL. My current approach is to call gdal_translate and gdalwarp using os.system and an ugly list of ground control points. I'd really like a way to do ...
7
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191 views

Geotransformation for polar stereographic?

I'm currently working to import CANGRID climate data (provided as Surfer Grid ascii, ".grd" files) into ArcGIS. The grid is 95 rows by 125 columns in size.Metadata provides lat/lon of origin (lower ...
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2answers
87 views

Choosing country projections

Anyone know of a good reference (either pay or open-web) that details recommended country projections?
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24 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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2answers
510 views

Is it possible to automatically set CRS of Rasters from PRJ file?

I am trying to learn my colleagues to display measured data (ASCII) in maps relatively easily. I can prepare project, color and symbology style for the point layer and background map. I also found ...
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1answer
41 views

Set default projection of geometry objects in arcpy

I have a script that creates a polyline geometry from scratch using some math to generate coordinate pairs. At the same time, there is a user-defined polygon shapefile that is used to "erase" the ...
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27 views

Project lines onto surface in QGIS

This question may already be answered so please point me in the right direction. I am designing a water distribution system for a rural village in Guatemala. I have created contours for the area. I ...
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2answers
533 views

Project WGS84 to Google using MapGuide and WKT

I'm having trouble projecting a simple WGS84 formatted layer over google maps. I can't find a good WKT "API" that not only shows parameters, but explains what each parameter is. The coordinate system ...
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2answers
35 views

Correction spatial reference

Please assist me on how to use ArcCatalog to confirm the spatial reference is correct and adjust if necessary.
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1answer
63 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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80 views

calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
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47 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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2answers
106 views

Why has an orthographic projection been used in this NatGeo map?

I'm wondering why this maps uses an orthographic projection, resulting in 3 maps to view the whole world. What were the requirements or the reasons to choose this projection (why not Mercator ) ? ...
3
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1answer
86 views

Trouble calculating areas in QGIS using field calculator

I am testing various projections to calculate areas using ICES statistical shapefiles and the QGIS field calculator. I am using ICES areas downloadable from the following link: ...
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1answer
75 views

Difference between ETRS89 / ETRS-TM32 and ETRS89 / UTM zone 32N

In QGIS I can choose among other things between "ETRS89 / ETRS-TM32" and "ETRS89 / UTM zone 32N". In my test project both projections displayed the layers at the very same place. So, where is the ...
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1answer
58 views

QGIS crashing when using 'save as' to save a new projection

Every time I try to save a layer with a new projection using 'save as' my QGIS crashes. The new files are there but they seem false. Please see two screenshots attached, one before and one after I ...
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3answers
485 views

Is GeoServer getting coordinate output in GeoJSON WFS wrong?

When I do a WFS request to GeoServer and specify the SRS like this: http://myserver.com/geoserver/wfs? service=wfs& version=2.0.0& request=GetFeature& ...
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219 views

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
164 views

Difference between NAD83 Indiana SPW in QGIS and ArcGIS for Desktop?

It seems ESRI and QGIS don't have the same definition for my most commonly used projection, NAD83 StatePlane Indiana West (US ft). When I create data in an ESRI product the projection shows up in ...
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2answers
119 views

Is there a standard for the specification of .prj files?

We use shape files for data exchange. I've looked at the .prj files: different programs produce different prj files. Is there a standard how the parameters must be specified in a prj file? AFAIK the ...
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1answer
58 views

Problem with projection of Slovenian Shapefile in QGIS

I hope someone can help me for this: I'm doing my masters thesis in Slovenia (in the field of wildlife management), for this I got a Shapefile of slovenian data by the University. As a main layer, I ...
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1answer
71 views

Proper projected coordinate system for Minnesota for measuring areas

I have seen in ArcGIS many different State Plane systems for Minnesota (location coordinates in WGS84: 44,07 lat/-94,61 long) within the Projected Coordinate system group: NAD 1983 (CORS 96) ...
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29 views

Pros and Cons of a latitude adjustment grid vs other methods of area calculations

When working with high resolution global raster data in WGS 1984 I often need to calculate areas. Now the traditional way for me to achieve this has been to reproject the data to an equal area ...
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7answers
1k views

Spatial reference for dummies?

Can anyone recommend a good reference or tutorial that explains the principles of spatial references, projections, and coordinate systems? We are a small team of programmers working with GIS ...
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1answer
56 views

How can I reproject a layer in a spatialite database

I'm writing an android mobile application and, for performance reasons, I want to reproject my layers to match the basemap's projection. Is there a command to do that?
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30 views

How can one use Google Maps API to mimic QGIS projection/CRS

I used QGIS to find the extents of a list of features. However, the resulting data auto-generates the CRS and changes it from WSG84 to a custom one. Is there a way to use the autogenerated CRS in ...
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118 views

TileStache : Unknown geometry type in geoJSON file

I'm currently trying to set up a TilSstache server on Ubuntu 12.04 to serve some GeoJSON tiles from a shapefile/JSON file (administratives boundaries) for a web mapping project using the Leaflet ...
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1answer
32 views

Difference between source SRS and target SRS in Raster Warp function

Hello I am trying to change a raster layer projections from WGS84 to a custom Lambert layer using 'Raster' --> 'Projections' --> 'Warp' function. I have been asked for source SRS and get SRS. what is ...
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6answers
8k views

Shapefile PRJ to PostGIS SRID lookup table?

I was wondering if there is such a thing as an shapefile PRJ to PostGIS SRID lookup table? Something that can translate the most standard shapefile PRJ definitions into the likely SRID. When using ...
2
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2answers
41 views

Custom projection problem with proj.4

I have some vector files that come without projection. So I have to define my own projection in QGIS. The information that comes with the data reads as following: Projection: Lambert Azimuthal Units: ...
2
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1answer
214 views

openlayers display projection

I'm displaying coordinates in epsg:900913 using ol.control.MousePosition() with OSM. I'd like to convert these on the fly in another epsg:2154. I call in the header : <script ...
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35 views

Precision loss when transforming coordinates systems in GDAL (vector layers)

Anybody knows the order of magnitude of the error introduced when transforming coordinates using GDAL? More specifically, I would like to know if significant error is introduced when the ...
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1answer
31 views

ArcMap Area Calculations vs MultiNet FEATAREA Field Discrepancy

I'm finding a huge discrepancy between the values supplied in the FEATAREA field in my MultiNet data and the area calculation results from ArcMap v10.2.2. In this case, I'm looking at the area of ...
3
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1answer
63 views

Is the bilinear resampling technique appropriate for the projection of ASTER data?

I need to project some ASTER data from a geographic coordinate system to a projected one. I have read online that the cubic resampling technique is the most appropriate for this purpose. However, ...
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212 views

Transforming between epsg:3857 and Google Maps Tile coordinates

Hio, I used to use a simple python project (https://github.com/hrldcpr/mercator.py) to convert between wgs84 and google maps tile coordinates. This project doesn't have a license, and looks like it ...
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19 views

Guessing a map projection by its values [duplicate]

This is more a theoretical question and not an actual problem that I have. Is it possible to identify or classify projections by their numerical coordinates? Or alternatively rule out in some sort of ...
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23 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 ...
9
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1answer
197 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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24 views

How to get ASTER level 1B data to overlay correctly on google earth/ bing maps/ arcmap imagery basemap

I have recently purchased Two granules of ASTER 1B data from ERSDAC. Upon importing this data into arcmap 10.2, the layers representing each band were specified as being projected in: ...
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1answer
55 views

How to import and project ASTER 1B data into Arcmap?

I recently purchased a granule of ASTER 1B data from ERSDAC, when I import any of the associated rasters into ArcGIS, the image is displayed as being only 1m across, when the actual area represented ...
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1answer
29 views

Short list of .prj options in .pyt

I'm tasked with creating a .pyt to distribute across our office and field computers (state geological survey) for converting .gpx to features but constraining the choice of projections/datums to seven ...
2
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3answers
139 views

Problem with Geometry SRID in PostGIS

I ceated my table (borne) in PostGIS id_borne serial NOT NULL, num_borne character varying, shape_borne geometry I successfully changed the SRID of my table using select ...
3
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2answers
51 views

Choosing projection to use for Least-Cost Path analysis at continental scale?

I am trying to find least cost paths from the southern USA to the Great Lakes region (for example). My resistance layers are currently in an equal area projection but I'm wondering if I should convert ...
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1answer
62 views

correct projection of GADM data

I'm trying to use a map of Austrias districts from the GADM project. The Shapefile can be found here: AUT_adm.zip (All other formats provided by the project appear exectly equal.) The coordinate ...
0
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2answers
136 views

GDAL for Python: extracting subdomains from NetCDF file?

I need to make a script that processes a NetCDF file that contains 3 days of hourly forecast data from the norwegian meteorological office. The NetCDF file contains various data I need ...
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22k 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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216 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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1answer
91 views

Reprojected Shapefile does not align with Openlayers Plugin

I am based in NSW, Australia. I have a shapefile that when I underlay with the openlayer plugin (google satellite), the shapefile is skewed despite all my efforts to correct it. I changed the ...