The process of converting the coordinates of a map or an image from one system to another, typically by shifting, rotating, scaling, skewing, or projecting them.

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154 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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95 views

Node.js transformation from NAD83 to WGS84

I've used the excellent npm shapefile library to import Canadian electoral districts into MongoDB. Here's a sample file: http://ftp2.cits.rncan.gc.ca/pub/geott/electoral/2011/fed308.2011.zip Is ...
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1answer
433 views

Problem with Converting XY Coordinates to LatLon

Here is the function that I use to convert from pixel x,y to lat,lon coordinate: public static Coordinate imageToWorld(Dataset gds, int x, int y) { double[] adfGeoTransform = new ...
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1answer
520 views

PROJ4 / PostGIS transformations between WGS84 and NAD83 transformations in Alaska

I'm trying to implement the recommended WGS84 - NAD83 transformation for Alaska using PostGIS. This post: Geographic Transformations in Alaska Between NAD83 and WGS84 indicates the proper ...
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1answer
182 views

Distort image to display on leaflet.js based on known 16x16 point grid

I have an image that is a satellite picture, and with php gd I want to distort it so I can overlay it on a leaflet.js map. To make it a bit more simple, I have a grid of points, 16x16 which bind the ...
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3answers
2k views

Mercator: scale factor is changed along the meridians as a function of latitude?

"In Mercator projection the scale factor is changed along the meridians as a function of latitude" How to calculate the Mercator scale factor as a function of the latitude in decimal degrees ? ...
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43 views

Creating hierarchy of Feature Elements in MapForce

I use FME to translate SQLServer tables into gml document. In FME, I make one-one connections (every feature type produces new feature type in output). This document is not 'structured' as I want. ...
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143 views

Geodjango transform introduces large errors

Apologies for the possibly naive question. I'm trying to understand how Geodjango (running on PostGIS) deals with coordinate transformations, and am experiencing some unusual behaviour. Let's say I ...
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1answer
183 views

Why are my points being flipped or mirrored when I convert from DMS to DD?

I have a collection of crash data that provides latitude and longitude in degrees, minutes, and seconds that I'm converting to decimal degrees using: (degrees + (minutes/60.0) + (seconds/3600.0)) ...
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1answer
459 views

Translate coordinates in GeoJSON export

I am wondering if there is a way to apply a translation in coordinates for a GeoJSON export. Currently, there are negative coordinate values in my export, which I cannot have. I am trying to use ...
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2answers
87 views

Accurate local map projections

Is there a map projection that can accurately represent reality at a local area, i.e. when transforming the map could I choose an area that I care about accuracy and allow distortions elsewhere? Like ...
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0answers
39 views

EPSG1612 transformation [closed]

I have survey data for contacts listed as eastings and northings - I need to overlay this onto PNG files but the location is quite far north - How do I apply EPSG 1612 transformation to the UTM Zone ...
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1answer
321 views

Rotating markers for points in Tilemill along direction of a way

I have designed a simple marker to represent pedestrian crossings, which in OpenStreetMap data are represented as nodes (points) along the way (line). I want to rotate the marker to follow the line it ...
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1answer
338 views

Moving a shape around the earth while maintaining the proper projection

What is the transformation needed to be taken on every data point of a shape to rotate that shape around the globe. I'm trying to figure out the math behind this kind of transformation so I can ...
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3answers
102 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!
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2answers
233 views

Any difference between EPSG:3003 and EPSG:102091?

I am working on QGIS 2.2.0. The PRS I am working on is Monte Mario / Italy zone 1 (EPSG:3003), with the following parameters: PROJCS["Monte Mario / Italy zone 1", GEOGCS["Monte Mario", DATUM["...
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1answer
363 views

Shifting a CAD file from ATS77 MTM 5 to NAD83 CSRS UTM 20

Looking to make the coordinate system shift in ArcMAP (for Nova Scotia) between ATS77 MTM 5 and NAD83 CSRS...NTv2 file?
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1answer
331 views

Help with “projected XY to screen xy” conversion algorithm?

I'm trying to convert coordinates from any given coordinate system (be they the coordinates of a graph figure or a map, meaning they can span across both negative and positive values across any of the ...
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1answer
245 views

Find AB_CSRS.gsb for NAD_1983_TO_WGS_1984_8 Transformation

I am trying to change my WGS84 data to NAD83 for Alberta data. My research tells me that I need to use the NAD_1983_TO_WGS_1984_8 Datum Transformation which is in the AB_CSRS.gsb. I can not find this ...
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1answer
158 views

Can I define a transformation between 2D and 3D in Geotools?

I'm using Geotools, and I need to convert coordinates between 2D and 3D coordinate reference systems. I recognize that there's no universally-correct way to do this: 2D -> 3D means "making up" a Z ...
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2answers
177 views

Defining a scale number from the Helmert transformation

I know this is more bit of a cartographic issue, but maybe somebody would be able to help. I have an old map georeferenced to the openstreetmap with 50 identical points. I want to get the scale of the ...
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2answers
130 views

How to replicate ArcGIS coordinate transformation with ogr2ogr?

I need to be able to replicate with ogr2ogr a coordinate transformation that was executed in ArcGIS for Desktop. Both ArcGIS and ogr2ogr are based on EPSG standard definition. There's not only one ...
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1answer
178 views

How to surround a Polygon object with a corridor of specified width?

I'd like to build a corridor surrounding a polygon, so that the corridor's outer bounds all have the same distance to the inner bounds. Like this: I've made this lousy graphic in Paint, since I don'...
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1answer
104 views

ArcGIS: How to affect graphics in a MXD by a geographic transformation?

Our GIS users have been using graphics to mark things in their map documents. By graphics, I mean circles, rectangles, lines, text, etc. that can be drawn into data view by using the Draw toolbar. We ...
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954 views

Rotating the coordinates of a layer by 90 degrees

I have got a dwg file with the plans for a building, with rooms and everything. (There's been some samples taken inside the building which I want to display.) Now, since it's of a building, the person ...
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2answers
194 views

How do I transform a raster image to one with rounded corners (cylindrical to pseudocylindrical)?

I've been working with the altimetry data from topex.ucsd.edu/WWW_html/mar_grav.html Was having difficulties extracting the data, so I wrote a simple tool to do that. Creates a bitmap form the data ...
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3answers
7k views

Convert geometry to latitude-longitude using PostGIS ST_Transform

My table has a geometric field, in EPSG:3857, of type point. I need the latitude and longitude, in EPSG: 4326, of each point. Could someone give me a valid example of how to use ST_Transform().
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2answers
156 views

Transform coordinates from NOAA

I use data from NOAA for some analysis in R and I want to transform coordinates to EPSG:54004 or something useful. There is something what they write about their coordinates. ... POS: 29-34 ...
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1answer
170 views

How to resolve a 'Received NULL pointer' ArgumentOutOfRangeException for OSGeo.OGR.Geometry.TransformTo?

I am attempting to project a geometry using the GDAL c# bindings and I'm getting a ArgumentOutOfRangeException ('Received NULL pointer') exception on the Transform methods of Geometry. I'm also ...
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1answer
197 views

Bad calculations with Colombian projection (EPSG:3116) in GeoTools?

Solved, reading mail-archive I can understand that there is a conflict between: gt-epsg-wkt-9.2.jar gt-epsg-hsql-9.2.jar I tested removing each one, with 'hsql' I get the same wrong result, but ...
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1answer
206 views

How to apply Log Transform to Flow Accumulation?

I have run a flow accumulation for a DEM that I'm working with. I'm trying to apply a log transform because I've heard it could give a better visual representation. How would I go about doing this ...
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1answer
157 views

PostGIS transform geometry with long crs

How do i transform a geometry to a new geometry with a crs like urn:ogc:def:crs:EPSG::25832 st_transform(geom,integer srid) obviously doesn't work since my srid is a string found a solution ...
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1k views

Geographic Transformations in Alaska Between NAD83 and WGS84

I have done a ton of research on the most accurate transformation to use in mainland Alaska to convert between the NAD83 and WGS84 datums, but I just can't seem to find a definitive answer. ArcMap ...
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91 views

Transformation of OGR style data

I have been using GDAL/OGR in a project and it is going quite well. I have been re-projecting data from various source formats into a single CRS (using the C# bindings), but one issue I have come ...
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1answer
2k views

Using Affine Transformation to expand polygons in QGIS

I have a shape file, and I'd like to grow each feature by 13.7% or 14%. The program crashes every-time I try to use affine transformation. Any recommendations? I don't have a license for ARCgis. ...
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2answers
125 views

Is transformation of spatial data lossy?

I have a shapefile that contains data of a country from the following Geographic Coordinate System ( GCS_North_American_1927 aka NAD27 ) contents from the shape file .prj: GEOGCS["...
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1answer
225 views

QGIS 2.0: move basemap by hand in order to achieve overlaying with a point layer

I am an environmental engineer and the aim of my QGIS 2.0 project is to visualize the results of a sewage water system inspection. In a first step I included the hoppers from a csv file and added a ...
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1answer
537 views

How to automatically transform between base layer and vector layer in OpenLayers

I have a simple example on http://jsfiddle.net/29bsw/ I have a map with an OSM layer as base layer and an additional vector layer. The projection of the map is defined as EPSG:900913 and the ...
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1answer
174 views

How can I carry out a reliable coordinate transformation for point data?

I have ArcGIS 10.0 with ArcGIS Server (AGS) 10.0. Due to a known bug in the AGS geometry service we cannot carry out coordinate transformations with AGS 10.0. Our Internet client therefore does not ...
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45 views

QGIS layer only displays when I uncheck on-the-fly transformation

I have a layer that covers the stats of Indiana that has the following Layer SRS: +proj=utm +zone=16 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs It will not display unless I uncheck the on-...
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1answer
252 views

QGIS with CH1903/LV03 and WGS84 layers

I have a few CH1903/LV03 layers (lake, river and the country border of Switzerland) and a layer in WGS84 (two points of two cities, Vaduz and Bregenz). On-the-fly-transformation is activated but ...
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1answer
145 views

Problem while Reprojecting

When I try to transform geometries from SRID 2321 to 4326, the transformed coordinates are swapping. Why is this happening? Below are the details Source SRID - EPSG:2321 Source Data Projection ...
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2answers
246 views

Problems with transformations in ArcMap

I have files projected in British National Grid. After I have transformed them into WGS_1984. I noticed that if I were to transform them back to BNG the original would not match the new. Is there a ...
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1answer
270 views

How can I transform Real-time Local position system coordinates into GPS/WGS84?

I have a local coordinate system built with Ubisense sensors and tags (it is a real-time locating system used to automatically identify and track the location of objects or people). The local ...
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1answer
873 views

Why is tiff different in epsg 3857 and epsg 900913 in gdal

When I transform tiff from 4326 to 3857 and from 4326 to 900913 in gdal, I get different result(when display in Qgis) eventhough these two projections(3857 and 900913) should be the same. What is ...
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1answer
3k views

From GCS_WGS_1984 to UTM WGS 84 zone 33N

I was doing my project and i had to transform shapefile from bessel to gcs_wgs_1984. that went fine. Now I have to put it again to projected coordinate system. Please could someone help me transform ...
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1answer
392 views

FME: how to extract the coordinate of the North West corner

In an FME translation from a polygon geodatabase feature class to a DGN I am trying to place a label in the top left corner of a box. I have tried using CoordinateExtractor to find the coordinates of ...
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1answer
308 views

Buffer Zip Region Polygon with GeoTools

What I want to achieve is to buffer a zip region geometry with a distance in meters and than get the coordinates of the new (expanded) polygon. The original geometry polygon is parsed from a kml file. ...
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2answers
537 views

Is there a vector affine transformation tool in QGIS2?

In QGIS 1.8, I can transform my point layer with the plugin "Affine transformation". So, this plugin don't exist in QGIS 2.0. Do you know a method to simply translate (i.e : X -> X+30000) in QGIS 2 ? ...
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1answer
4k views

Trasformation from ECEF to ENU

I am trying to transform a local vector rECEF from ECEF coordinate system to ENU coordinate system (rENU) where ECEF = earth-centered earth-fixed coordinate system ENU = East, North, Up coordinates, ...