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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projection conversion from mercator to google maps format

Is this spTransform(Finland3, CRS("+proj=longlat +ellps=WGS84 +no_defs+ellps=WGS84 +towgs84=0,0,0 ")) the right way to project a shapefile with this projection coord. ref. : +proj=merc +lon_0=0 ...
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3answers
582 views

Why are Data Projections relevant?

Why is it useful to store data in unusual projections and datums? I understand the value of projections as output constructs, because of distortion, etc: that much is justifiable. However, I don't ...
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1answer
36 views

How to center a user-defined CRS on an area of interest?

My study extent in central Iran straddles two UTM zones (39 and 40): I would like to create a user-defined CRS in Transverse Mercator projection with central meridian inside this area. Through ...
6
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1answer
569 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
30 views

Projected raster data has inconsistent extent but not shapefile

I want to calculate the average value of a raster file within each polygon boundary of my shapefile. Because I want to preserve area I wish to use the Goode Homolosine (Land) projection. The original ...
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2answers
641 views

How to create a Winkel-Tripel map of countries with different colors?

I need a good quality rasterized world map, Winkel-Tripel projection, in which all countries have different (random?) colors. No borders, text, grid or anything else on the map. Is GIS the right way ...
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1answer
35 views

GDAL -SQL or -where options

ogr2ogr -overwrite -t_srs EPSG:3978 -f "ESRI Shapefile" -sql "SELECT * FROM 'Layer Name' WHERE FIELD_NAME = 'A CLASS'" dst.shp src.shp help me out here - looking to 1) reproject a shape and 2) ...
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1answer
37 views

Proj4 for EPSG3857

I am using leaflet and the R library sp. The CRS from my leaflet map is EPSG3857 - WGS84 Web Mercator. I am retrieving the coordinates of my current map view with getBounds(). For further calculations ...
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1answer
551 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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0answers
30 views

Using the projection of a layer variable to project another in ModelBuilder in ArcGIS (vector version) [closed]

I have several shapefiles in a folder (Folder X) with different coordinate systems (Proj 1 - eg. SAD69_UTM_Zone_21, SAD69_UTM_Zone_24) and another shapefile (shapefile 2) with another specific ...
2
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0answers
25 views

Converting from flat earth to WGS84 with python

I'm looking to move from basic 2d Cartesian coordinate system into WGS84. I know my starting coordinates, however all intermediate points are x/y/z points. of an origin 0,0,0 . Mathlab has a ...
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1answer
267 views

Displaying a map in EPSG:26915 projection in open layers 3

My GIS experience is limited to having worked on several Geospatial Humanities projects. That is to say that I still struggle significantly with the technology (and terminology) in getting to my goal. ...
2
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3answers
50 views

How to find the extent of (many) EPSG CRSes?

I want to map the geographic extents / bounding boxes of a lot of EPSG CRSes. At least, those with a rectangular geographic extent. For example, take epsg:2004, visiting that page shows the extent ...
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2answers
26 views

How to define a coordinate reference system with rotation in GeoServer?

I am using GeoServer and have a layer in EPSG:900913 ("Google Mercator"). I need to "rotate" the map around certain point (say, 1500000, 7000000) by certain degree (say, 30 degrees clockwise). How ...
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1answer
26 views

How to convert shapefile of India into a system with longitude and latitude system?

I have two shapefiles of India. One is without PoK and other is with Pok. I want to convert the shapefile of India with PoK into a co-ordinate system with longitude and latitude (same as without PoK). ...
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0answers
17 views

Matching d3.js geo projection with pyproj Proj4

I am having trouble figuring out the correct notation for Proj4 projections with pyproj. I got the following projection in d3.js and I want to match it with pyproj on my backend to send a background ...
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5answers
178 views

Fisheye-like projection

I need a special projection for the purpose of effective presentation on a poster. I'd like to present the study area (Czech republic) in a context of whole Europe in such a way, that the Czech ...
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0answers
22 views

Project Raster: Resampling

Is this (optional) resampling technique in the Project Raster tool only being used if changing the grid resolution (cell size)? Or should I always select bilinear (or cubic) for continuous data even ...
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0answers
30 views

Projecting a world map on 6 segments to print on ball

Working with QGis and data from Natural Earth I would like to prepare a world map (1:50 000) for a globe that can be printed in 6 segments, which glued together build a ‘sphere’ (ball) according to ...
9
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2answers
200 views

Why do I get correct area and intersect area when use wrong projection?

I need to calculate areas and intersection areas for polygons (some real geographical objects like lake, city, country, e.t.c.). Polygons located in California, New Zealand, Russia.Anadyr, Sweden All ...
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0answers
25 views

Geographic Coordinate System NAD 1983 vs Projected Coordinate System NAD 1983 & Projections

I am working on a project utilizing free data from http://www.pasda.psu.edu/, specifically data from PennDot, 2015 Pennsylvania County Boundaries ...
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1answer
33 views

How should I work with Layers with different projections in openlayers-3?

I'm using openlayers-3.8.2. I have some ol.layer.Tile layers and ol.layer.Vector layers. The projection of ol.layer.Tile layers and ol.layer.Vector layers are different. ol.layer.Tile layers work with ...
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2answers
44 views

How can I convert points in EPSG:2956 to EPSG:4326 with pyproj?

I have some points in EPSG:4326 -110.28879750 64.46310187 405.49938863 -110.28879359 64.46310086 405.45967110 -110.28880175 64.46310446 405.93823604 -110.28880245 64.46310258 405.48060850 ...
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1answer
251 views

GDAL - projection from pixels to geo coordinates

I am using GDAL library in C++. On my dataset, I have obtained geo transform with GetGeoTransform to GT array (GCP is NULL). Than I use this values for this equation (Source): Xgeo = GT(0) + ...
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2answers
948 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
52 views

Converting from kilometers to degrees distances?

We have geometries in a Postgis database with SRID WGS84 and we have found lookups directly in degrees to be much faster than in kilometres, because the database can skip the projections I would ...
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0answers
24 views

raster data and polyline shapefile do not line up

I am working on an ArcMap .mxd encompassing the state of new mexico. I have a shapefile of the state boundary with the following coordinate system GCS_North_American_1983 WKID: 4269 Authority: EPSG ...
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1answer
14 views

How to get geodetic area? rgeos::gArea doesn't seem to work. Or area-preserving projection

I need to get an area of different polygons at continental scale (like third of Africa etc.). Usual functions like rgeos::gArea work only in the projection units. Is there any function which works ...
0
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1answer
15 views

Measuring different values in latlong Geotiff whether OTFR enabled or not

I'm using a GeoTiff file in QGis that has no projection per-se (it uses lat-long coordinates) and WGS84 datum. Further it has an x pixel size of 2.40475e-07 degrees and a y pixel size of ...
2
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2answers
57 views

Is there a way to get undistorted maps in R (when using the OpenStreetMap package)?

When I download a large map within R (using the OpenStreetMap package) and I reproject the map (ideally to +proj=longlat), the map will always turn out distorted, making country labels etc. near the ...
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1answer
202 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 ...
1
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2answers
273 views

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 Openstreet map within a website. Since I was not able to change the projection earlier, I decided to manipulate the ...
0
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1answer
29 views

Map Projection - Why don't we draw things out

I have been reading about different map projections and kind of understand where the problem lies. And also, most of the problem was that the old cartographers did not have any other tool other than ...
4
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1answer
141 views

How do I find/define a projection that gives me exact relative positions inside an area?

Assuming that a set of positions are all inside a 5km square area: How do I find/define a projection to reproject the positions, so that the relative positions between the now reprojected positions ...
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0answers
43 views

How to choose a projection for area measurement on building to continental scales?

I have many geographical objects described as polylines, polygons, multipolygons. All objects are in WGS84. Object could be: a building, stadium, park, street, highway, city, state, even country and ...
1
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1answer
29 views

Atlas with different projections in QGIS

I have created an atlas -- i.e. a map with a layer defining some regions of interest -- in QGIS. I can render maps of each region using the "atlas" feature of the print composer, but I want to show ...
0
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3answers
79 views

How to set a coordinate transformation GRID

Does anyone know how to set a coordinate transformation in qgis so I can measure the distances in meters or kilometers? If anyone has a clue, would be just great. Thanks!
2
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3answers
274 views

How are ESRI WKT projections different from OGC WKT projections?

Does anyone know the precise list of differences between esri wkt and ogc wkt projection format strings? I know there are various tools to help convert from esri wkt to ogc wkt, incl gdal utilities ...
3
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2answers
1k views

How to understand GeoTIFF tags?

I'm trying to understand GeoTIFF info, but not getting far. For instance, using listgeo with one file I can get this output: Geotiff_Information: Version: 1 Key_Revision: 1.0 ...
0
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1answer
36 views

MapInfo Point Object Dialogue is different to Info Tool's Transformed XY

A MapInfo Professional 11.0.3 user has re-projected data from AGD84 Zone 50 to WGS 84. However when they select a point and look at the point objects's X and Y, they are different to what's reported ...
2
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1answer
63 views

After how much distance does the x,y coordinate system become noticeably distorted?

I'm working with maritime sensors that give information of moving objects it detects, in azimuth, range and elevation, and we convert it to x,y coordinates for our application to be able to process ...
1
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2answers
21 views

Is publishing geodata in unprojected latlon coordinates better than a local UTM projection?

This is meant as some kind of reference Q&A. Unless I am working with truly global data, I always prefer projected, local, metric coordinates so that calculations like area or distances are ...
4
votes
2answers
1k views

Create custom projection using either QGIS (or ArcGIS Desktop)?

I have searched for an answer to this but don't see anything relating to what I am trying to do. What I have are a series of Geographic Coordinates, Latitude, Longitude, Ellipsoid heights. What I ...
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1answer
326 views

How can I project geojson borders on the google earth tiles in leaflet?

I started working with leaflet and google earth tiles. I want to add borders on my map so I tried to use the countries geoJson Data as a layer on the map. The problem is that the json borders ...
2
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1answer
25 views

OTF reprojection and reprojecting layer not working in QGIS

more troubles in QGIS. I georeferenced this raster in Corrego Alegre UTM23S and loaded up, so project CRS automatically changed to that. So far so good. I need it to be however in WGS84 UTM 23S. None ...
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1answer
159 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 ...
1
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2answers
40 views

Defining the azimuthal equidistant projection of an Environment Canada weather radar map

Environment Canada helpfully provides recent captures of all national weather radar stations at http://dd.meteo.gc.ca/radar/PRECIPET/GIF/ at ten minute intervals. These are the same GIF images as ...
3
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2answers
57 views

Projection issues whilst opening shapefile in ArcMap created in QGIS

I created a polygon shapefile in QGIS. Projection was saved as EPSG: 3857, WGS 84 / Pseudo Mercator. When I open this shapefile in ArcMap the projection sets itself as WGS_84_World_Mercator which I ...
2
votes
3answers
115 views

How to project a layer from WGS84 lat/long (automatic projection) to WGS 84 UTM Zone 23S in QGIS?

So I have a vector layer of polygons in WGS 84 lat/long (i.e. using the automatic projection for lat/long and WGS84 datum). I want to change that to WGS84 UTM 23S in QGIS. I tried doing like online ...
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0answers
35 views

Impossible to define the shapefile projection properly [duplicate]

I downloaded some dataset from Hot Export. By default they don't have any projection or coordinate system defined. The only thing I can see is the Feature Extent with values such as: Max Y ...