The process of translating a map or spatial data from one geographic projection to another

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37
votes
3answers
42k 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 ...
28
votes
1answer
3k views

Coordinate system for calculating areas of polygons accurately?

I have multiple polygons, all located offshore around the UK. I am trying to calculate the areas of these polygons in square kilometres, without splitting them by UTM zone. Is it possible to do this ...
21
votes
2answers
22k views

How to reproject a vector layer in QGIS?

I have some shape file which is in UTM. I wanted them to convert to Decimal Degrees in QGIS.
5
votes
1answer
1k views

Raster incorrectly reprojected to OSGB(27700)

Ubuntu 12.04, QGIS 1.8.0, GDAL/OGR 1.7.3, GEOS 3.2.2 Open a Spatialite db with OS Mastermap poly layer (EPSG:27700); Add OpenLayers Plugin (1.0) from QGIS offical repository; Add a Google Satellite ...
6
votes
3answers
4k views

Using ArcObjects to choose GeoTransformation?

I’m currently building a Desktop add-in tool with ArcObjects that: Asks a user to select a feature class Reprojects the feature class to Web Mercator Executes some geoprocessing The initial ...
25
votes
3answers
10k views

Reprojecting all geometries in PostGIS table?

I created a spatial table with SRID:4326. Now I want to change total projection to SRID:32644 into a new table. The old table should remain unchanged.
25
votes
2answers
17k views

What is the difference between EPSG:900913 and EPSG:3857?

I'm using the QGIS google layers plugin to digitize a parcel as a shapefile. Later I want to import it to PostGIS. I know that google maps use a special 'google mercator' projection. What is the ...
9
votes
1answer
6k views

How to reproject a raster file in QGIS with datum transformation?

I want to reproject a tiff raster file from projection A (ETRS89/UTM Zone 32) to projection B (DHDN/Gauss-Kruger zone 2). The two projections have a different datum so I have to use a datum ...
19
votes
5answers
14k views

Map projection in OpenLayers

I want to overlay some data whose projection is WGS-84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows: map = new OpenLayers.Map('map', { ...
15
votes
1answer
16k views

Projecting sp objects in R

I have a number of shapefiles in different CRSs (mostly WGS84 lat/lon) that I'd like to transform into a common projection (likely Albers Equal Area Conic, but I may ask for help on choosing in ...
53
votes
8answers
2k views

One dimensional map of the world?

Bit of a strange question but hope this is OK to ask here. Has anyone heard of a '1-dimensional' projection of the world map - that is mapping all the points on the globe to a single line? I was ...
11
votes
2answers
16k views

How to enable projection transformation in QGIS

My QGIS project has two layers, one layer is retrieved by Google layer plugin which fetches the static Google map image whose CRS is +proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +...
10
votes
3answers
12k views

Converting X,Y coordinates to lat/long using pyproj and Proj.4 returns the wrong coordinates

I'm writing a python script that reads multiple XML files containing x and y coordinates and combines them all into a single csv file. Latitude and Longitude are required fields in the csv, but I am ...
4
votes
1answer
776 views

How to match a raster NetCDF data with a vector layer in QGIS?

When I load a raster layer with humidity data from NOAA database (for instance rhum.2m.2014.nc at ftp://ftp.cdc.noaa.gov/Datasets/NARR/Dailies/monolevel/) I am not able to match it with a simple map ...
3
votes
2answers
22k views

How to convert coordinates from meters to decimal degrees?

I have a shape file. The coordinates (Lat/Long) are projected as meter (555000, 155000). But, I want to re-project it to decimal degrees(51.523666, -0.07467). How can I do it with ArcMap or Quantum ...
4
votes
4answers
240 views

Lines on reprojected sp objects with Mollweide projection

I'm having an odd problem such that when I reproject maps to a Mollweide projection in R using sp, I get additional lines stretching across the globe. What is going on here, and do you have any ...
11
votes
10answers
11k views

Batch convert lat longs to UTM?

I've got a .csv file that contains a long list of latitude and longitude points. Is there an efficient way to batch convert the list into a projected UTM coordinate system? Thanks.
2
votes
0answers
1k views

OSGB36 to WGS84 reprojection 'error'

First off, I am a recent convert to QGIS and am greatly impressed with its ease of use and speed compared with the ESRI products with which I am more familiar - my congratulations and thanks to its ...
2
votes
3answers
995 views

Can I use Openlayers Plugin with a different Datum/Projection?

There is probably already a post for my problem, but after long searching, I could not find a solution for my issue. I am working with QGIS und I am using the following projection/datum: MGI / ...
11
votes
2answers
2k views

How can I improve my Georeferencing results?

Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
5
votes
1answer
464 views

Reprojecting LiDAR data with libLAS

I have a lidar file (file.las) with the following spatial reference: Spatial Reference: PROJCS["NAD83 / UTM zone 11N", GEOGCS["NAD83", DATUM["North_American_Datum_1983", ...
5
votes
3answers
10k views

Using the Proj4js library to convert from Google Maps to projected values

I'm using the proj4s javascript library (based on advice from this question I asked previously) to convert lat/long values on my webpage. This page receives the lat/long values from google maps and ...
14
votes
5answers
2k views

Does Re-Projecting ShapeFile only update content of *.prj file?

if i wish to change the projection of some shapefiles from .. lets say NAD83 (4269) to WGS84 (4326) ... and by using some 3rd party app .... does this mean the .prj file is only updated .. and not the ...
5
votes
1answer
11k views

Transforming from SRID 900913 to 4326 with PostGis

I have two Postgres tables with different SRIDs: 4326 and 900913. I want to convert the latter to 4326. I first changed the SRID using: Select UpdateGeometrySRID('table', 'geomcolumn', 4326). I ...
4
votes
1answer
168 views

Why are raster z-values changed when reprojecting?

I have raster data with height values (z). When I try to reproject/warp the raster to Gauss Kruger 3, the z-values are changing (several meters). (The data is already GK3, but I have to reproject them,...
3
votes
3answers
1k views

Which UTM zone to use for a large country?

I want to reproject OpenStreetMap roads data from the current projection (WGS 84) to UTM, since I read in another GIS.SE discussion (How to get $length in meters in QGIS?) that WGS 84 cannot be used ...
12
votes
2answers
2k views

Reprojecting WGS 1984 Web Mercator (EPSG:3857) in Python with GDAL

I am reprojecting rasters in python using GDAL. I need to project several tiffs from geographic WGS 84 coordinates to WGS 1984 Web Mercator (Auxiliary Sphere), in order to use them later in Openlayers ...
4
votes
2answers
930 views

What's the best projection for rasterization of random latitude and longitude data in the northern Atlantic?

I have a dataset in the WGS84 geographic coordinate system that I would like to interpolate along a grid using Python. It appears gdal_grid is not available through the Python bindings, so I plan to ...
4
votes
1answer
461 views

QGIS: Plot a layer given with Longitudes [0 360] to [-180 180]

I have a world map in correct Longitudes from -180° to 180°. Additionally, I have a shapefile of data from South America, which shows at 290° instead of -70°. How can I reproject it using QGIS?
3
votes
1answer
3k views

Re-project raster image from Mercator to Equirectangular

I have a raster image of the world map in Mercator projection, square 1:1 format. I want transform the image into an Equirectangular projection accurately. I assumed from my research that GDAL would ...
2
votes
1answer
3k views

Convert area from square meters to degrees globally

I have a global raster file with 3600x1800 pixels. I don't have any information about the projection used. The raster contains one band with a quantity with the unit "per square meter". How can I ...
2
votes
2answers
2k views

How to display distance in meters (km) and not in Decimal Degrees in QGIS 2.4?

I am a GIS beginner, and I have a question about how to get the distance between two points in meters instead of decimal degree. In QGIS 2.4 I have a project with two point layers (in WGS84). From ...
10
votes
2answers
257 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 ...
6
votes
5answers
3k views

Can I copy an entire geodatabase with relationship classes and domains and reproject all feature classes from wgs84 to state plane?

I have an SDE geodatabase with several feature classes, tables, relationship classes, and domains. All the feature classes are currently in WGS84 coordinate system. I need an exact copy of the ...
6
votes
3answers
3k views

How can I find out how to convert this point to lat lon?

I have received a shapefile with measurement points to be analyzed, but no matter how I try, I can't find how to convert to lat lon. I suppose it would be good to know the projection but when I look ...
5
votes
2answers
6k views

Convert x, y position in georeferenced image (with world file) to longitude, latitude?

What steps do I need to do in order to calculate longitude and latitude for a specific pixel in a georeferenced image? For example this image http://www.shadedreliefarchive.com/...
4
votes
2answers
476 views

Reproject TM65 to OSGB in ArcGIS

I have a TIFF file in the TM65 (Transverse Mercator) projection, and want to convert it to the OSGB (British National Grid) projection. I'm trying to do this in ArcGIS using the Project Raster tool. ...
4
votes
2answers
401 views

How to Intersect a layer with custom CRS with NED data?

I am trying to create a map with a layer of county tax assessor property parcels plus NED elevation data. The projection of the tax assessor layer is a weirdo -- looks like user-created by the ...
3
votes
2answers
767 views

Reprojecting Natural Earth raster into natearth projection with gdalwarp causing black squares?

I'm trying to reproject the Natural Earth 2 raster layer (http://www.naturalearthdata.com/downloads/10m-raster-data/10m-natural-earth-2/) into the natural earth projection (http://en.wikipedia.org/...
2
votes
2answers
9k views

How to create custom coordinate system in ArcGIS Desktop?

I have a series of control points with xy coordinates in both NAD83 UTM and in a local grid. How can I go about creating a new projection file in ArcGIS 10 for the local grid?
1
vote
1answer
579 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 think....
1
vote
1answer
627 views

Creating custom projections with Proj4

I'm reading into how to customise projections with Proj4 - specifically to achieve tilted projections such as the example below (from vis4.net) The Proj4 literature is pretty heavy going and having ...
1
vote
2answers
113 views

How can I make the UTMs of different datasets uniform?

I have wind datasets for every U.S. state and want to merge them. I found out that these datasets use different UTMs. So I want to make the UTMs uniform. How can I do that? This can not simply be done ...
1
vote
1answer
355 views

How to Buffer data in a Geographic coordinate system?

I am having an issue with buffer. My data is in Geographic coordinate system. I am trying to do a buffer of 600m and i am finding different results for each case, have tried thse so far: Map in web ...
0
votes
1answer
798 views

Reproject GeoJSON from EPSG:3857 to EPSG:4326

I am using this reproject tool to convert a GeoJSON point from EPSG:3857 to EPSG:4326. My command fails. What am I doing wrong? $ echo '{"type":"Point","coordinates":[-13720479.997764934,5688254....
0
votes
1answer
1k views

Re-projection in Geoserver

I have published a layer on Geoserver by cascading a remote WMS. i have successfully got all the layers from remote wms and publish one of those layers. But I want to re-project the layer from its ...
4
votes
2answers
9k views

Choosing the correct value for proj4string for shape file reading in R “MapTools”

I am having a shape file of polygons and another CSV file which contains a list of points as (Lat, Lng) pairs.. I want to check for each (lat, lng) pair from the CSV file which polygon does it fall ...
10
votes
2answers
4k views

Derive WGS84 Longitude & Latitude from British Northings & Eastings

I'm looking for a fairly simple way to append columns with WGS84 longitude and latitude to a table containing northings and eastings. The source data is Ordnance Survey's CodePoint Open, which I is ...
8
votes
3answers
1k views

1km circles around lat-long-points in many places in world

I have hundreds of lat-long-points spread around the world, and must create circle-polygons around each of them, with radius exactly 1000 meters. I understand the points must first be projected from ...
8
votes
2answers
593 views

More accurate way to calculate area of rasters

In my daily work, I am constantly asked to calculate areas of global raster datasets in geographic projection at 30 arc second resolution. These datasets are normally the result of a Combine operation ...