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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4answers
2k views

Rubber sheeting in GRASS or QGIS

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
14
votes
3answers
10k views

How to move vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it? Preferably using QGIS.
13
votes
4answers
3k views

How to reproject spatial data using free libraries?

How can I use free libraries to transform spatial data? For example, I want to change the projection of a Shapefile within the code of my C# web application. How do I do that?
11
votes
7answers
778 views

Where can I find GIS data to test GIS coordinate operations?

I am trying to find some data that can be used to test GIS coordinate operations from one CRS to another CRS. So far all I have found is the Gold Data set and also various example points in the EPSG ...
11
votes
2answers
785 views

Huge differences between results for 7-param datum transform

I'm trying to transform a WGS84 lat/lon point 11d42'32.10629" E 5d12'56.75371" S in three different software packages (Proj4, GeoTrans and Leica GeoOffice) but I receive very big differences ...
10
votes
2answers
13k views

Converting projected geoTiff to WGS84 with GDAL and Python

Apologies if the following question is somewhat stupid, but I am only VERY new to this whole GIS thing. I am trying to convert some projected geoTiff images to WGS84 using gdal in python. I have ...
10
votes
1answer
7k views

Characteristics of different methods to convert ECEF to LLA

I'm trying to convert ECEF (Earth Centered, Earth Fixed) coordinates, which are defined in X,Y,Z, centered at (0,0,0) to LLA (Latitude, Longitude, Altitude). There are a couple of methods I found on ...
9
votes
3answers
13k views

Understanding Coordinate System Transformation in ArcMap?

For the Data Frame Properties on a map in ArcMap, what is the difference between selecting a new coordinate system and using a Transformation?
9
votes
1answer
5k 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 ...
9
votes
1answer
2k views

How can I see the coordinate transformation parameters in QGIS?

How can I see (and edit if possible) the transformation method and parameters used by QGIS for "on-the-fly" transformation, and then for saving data in another CRS? Like in ArcGIS? Here is the ...
9
votes
2answers
448 views

How do I perform a 3 parameter geotransformation and projection in Sql Server 2012?

I have a table with latitude longitude (NAD27) columns in it. I compute two other columns, X and Y, representing Web Mercator (WGS84) location. Currently I'm using a Arcmap to do this, by applying ...
8
votes
4answers
12k views

How to reproject base layers in OpenLayers?

The issue is: I have vector/topo/image tiled maps for some places in north america which were published as ArcGIS Server REST service. These maps (A) are based in EPSG26912 projection. Now I wanna ...
8
votes
3answers
1k views

Retrieve polygon smallest MBR

I have a postgis table containing polygons. I want to transform my polygons to 4 points polygons : retrieve the smallest MBR. Here comes an illustration of what I want : My original polygon is ...
8
votes
1answer
2k views

Computational most efficient way to convert Cartesian to Geodetic Coordinates

As far as I understand the literature there are several ways to convert a set of geoecentric cartesian coordinates to geodetic coordinates Bowring, 1976 Borkowski, 1989 Lin & Wang, 1995 Toms, ...
8
votes
1answer
767 views

WGS72 to NAD83- how to find correct transformation

I am trying to get this raster file to convert from WGS72 to NAD83, but ArcMap10 doesn't appear to have the correct transformation listed. Where can I find this transformation, and/or how do I import ...
7
votes
3answers
1k views

How does ArcGIS determine which transformation to use when projecting on the fly?

How does ArcGIS determine which transformation to use when projecting on the fly? Where this would come in would be going from NAD 83 to WGS 84. Multiple transformations could be considered so how is ...
7
votes
1answer
2k views

How do I get a country border data set into my geography column?

I have a PostGis database with a multipolygon geography (as opposed to geometry) column. I'd like to fill it with the country border data available from ...
7
votes
1answer
322 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 ...
6
votes
2answers
5k views

How should I use GDAL to perform a transformation?

Greetings, I am a student who wishes to use GDAL to transform a series of images from Lambert Conformal Conic (EPSG: 9802) to Google Earth's WGS 84 (EPSG: 4326) for a web mapping project. I know ...
6
votes
2answers
3k views

Transformation parameters for Everest datum to WGS84

I have a shapefile with the following projection information: ...
6
votes
1answer
12k views

Transforming GCS_North_American_1983 to GCS_WGS_1984 using ArcGIS Desktop?

I posted Is there projection issue with Natural Resources Canada (NRC) Canada Atlas hydrology data? describing a shift in some of the NRC data (not all). Apparently, this shift has to do with ...
6
votes
2answers
1k views

Using British National Grid Transformation OSGB_1936_To_WGS_1984_NGA_7PAR in ArcGIS Desktop?

In ArcGIS 10 a new transformation has been added for converting between WGS84 and British National Grid. What is OSGB_1936_To_WGS_1984_NGA_7PAR? How should it be used when compared with the ...
6
votes
1answer
2k views

Python script to convert Lat Long to ITM (Irish Transverse Mercator)

I am currently working on a python script that converts Lat Long (WGS84) to ITM. The formulas used are based on a paper published by OSGB (Appendix B): ...
6
votes
1answer
528 views

locating latitude-longitude point in a piste-map with matrix transforms

I am trying to plot points of a particular latitude longitude on this image of a Swiss mountainous landscape. What I am doing is I have some 54 known location-points plotted on this image (not ...
5
votes
5answers
9k views

How to convert coordinates from Gauss-Krueger to Longitude/Latitude?

I'm a newbie in the GIS world so please advise me :) In my .NET/C# project I need to show some shapes/points on the Bing Map. The problem is I have the Gauss-Krueger coordinates and need to convert ...
5
votes
4answers
728 views

Given long, lat, x and y, how do I find the projection?

I am using an app called farsite that outputs shapefiles that show how forest fires will grow. I am getting output in coordinates as X and Y values rather than (lon,lat) and am looking for a ...
5
votes
1answer
2k views

Python - OGR: Transform coordinates from meter to decimal degrees

I have a point in a shapefile. The shapefile is in a WGS_1984_Web_Mercator Projected Coordinate System. I want to get the coordinates of that point in decimal degrees with GDAL/OGR in Python. I am ...
5
votes
1answer
3k views

Mercator projection: problem with latitude formula

I'm trying to get the position of a coordinate on this map (source Wikipedia): If I'm correct than the formula for the position of the latitude would be: R * ln(tan(pi/4 + latitude / 2)) But ...
5
votes
2answers
198 views

How to Convert Map Coordinates to Layout Coordinates in a rotated Dataframe?

I am trying to convert Map X and Y coordinates to corresponding Layout coordinates in a rotated dataframe. The code found in this post works fine, but only for unrotated dataframes. I've also found ...
5
votes
1answer
826 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 ...
5
votes
3answers
110 views

Are perpendicular lines still perpendicular after converting from UTM zone 15 to 16 (or between two neighboring zones)?

I want to convert a square polygon that is close to the edge of UTM zones 15N and 16N. The polygon's coordinates are in UTM 16N, but it is spatially positioned in the UTM15 area. My question is that ...
5
votes
2answers
197 views

Coordinate/projection system issue in ArcGis 10.3

I am new in this community and I am also a new user of ArcMap. I am facing a problem, my shapefiles are in a GCS WGS 1984 and I have to add a new shape file that is in a projected coordinate system ...
5
votes
1answer
170 views

Changing the projection transformation for a feature class after adding it to an mxd

Is there a way to select a different projection transformation after you've added a feature class to an mxd? I have a pretty complex mxd set up to use as a map service where the original data is in ...
5
votes
1answer
4k views

Converting Lambert Conformal Conic to WGS84 using Proj.4

I am attempting to transform data from Lambert Conformal Conic lat/long and I am having some issues with the results. The shapefile I am attemtping to transform can be found here: ...
5
votes
1answer
379 views

How much error in a transformation?

I've been working in GIS for about a year and have a functional grasp of Projections and Transformations from within ArcGIS (10.0). Geosoft Oasis is another program we use. In working with our data ...
5
votes
2answers
657 views

Translating all features in a shape file

I have a friend with a bit of a problem. He has 1000+ shape files mapping paddocks and being used for precision agriculture. He's recently discovered the base station positions used to create these ...
5
votes
2answers
769 views

Why are the coordinates transformed with proj.4 off compared to http://valdemar.kms.dk/trf/?

I am trying to transform from epsg:4326 (wgs84) to epsg:25832 (utm ETRS89) using Proj.4. I am comparing the results with results from http://valdemar.kms.dk/trf/ . it seems like the results ...
4
votes
1answer
10k 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
2answers
1k views

Transforming Shapely Polygon and MultiPolygon objects

Is there an easy way of transforming Shapely objects (namely, Polygons and MultiPolygons) from one projection to another without having to dig around and extract coordinates by hand? In fact, I ...
4
votes
3answers
2k views

generate spatial geom from lat lon points for map in PostGIS

I am interested in a PostGIS implementation of the R-based soulution from a previous question, How can I convert data in the form of lat, lon, value into a raster file using R? Currently, I am hoping ...
4
votes
2answers
542 views

Why Different 2D Coordinate Transformation Methods Exist

It is a homework question but I couldn't find a satisfactory answer by googling. There are 4 different transformation approaches I'm asked for: - Conformal, - Affine, - 2D Projective, - 2D Polynomial ...
4
votes
2answers
236 views

QGIS batch shp transform

I have a large number of shape files in OSGB (EPSG:7405), with no .prj file that I would like to convert to WGS84 (EPSG:4326). Can you let me know if this is possible in Qgis and, if so, how, and, if ...
4
votes
1answer
580 views

Experiencing transformation anomalies when performing a Save As to convert coordinates between NAD83-Z14 and NAD27-Z13

Good morning all: I have recently discovered QGIS and have been hoping to find a solution for converting bacthes of xy coordinates between two projection systems for our mapping system. I have known ...
4
votes
2answers
876 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
2answers
2k views

Coordinate system of a MODIS file to be introduced in GDAL for transformation

I am working on MODIS data using GDAL. When I extract coordinate system information of the files I got this: Coordinate System is: PROJCS["unnamed", GEOGCS["Unknown datum based upon the custom ...
4
votes
1answer
5k views

How to use OpenLayer.Transform?

I want to draw a rectangle. The coordinates are somewhere in northern Germany. But the rectangle shows up in the Near East? What am I doing wrong? var epsg900913 = new ...
4
votes
1answer
2k views

Transform shapefile to WGS:84 (EPSG: 4326) in Qgis

I am struggeling with an enoying problem here. I received several shapefiles from an colleague that he told me is in WGS:84. If I look at the metadata in Qgis it tells me the following: In layer ...
4
votes
2answers
486 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 ? ...
4
votes
2answers
486 views

GeometryServer > Project with Datum Transformation

I am facing the problem that when i use the extent in the url and i go from Amersfoort(WKID 4289) to WGS84(WKID 4326) that without the tranformation the point from longitude and latitude is placed ...
4
votes
2answers
970 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 ...