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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5k views

Rotating a vector layer in QGIS with qgsAffine (or other method)?

I would like to rotate a set of vector points in QGIS an arbitrary number of degrees around a central point (or arbitrary point). This is similar to a recent question about creating a regular grid; ...
6
votes
4answers
7k 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
1answer
2k 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 ...
5
votes
1answer
2k 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 ...
6
votes
2answers
4k 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 ...
14
votes
3answers
1k 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 ...
4
votes
1answer
3k views

Transforming geometry coordinates from SRID 4326 to SRID 3011

In SQLServer geometry field, I want to change the coordinates of geometry from one spatial reference system to another spatial reference system (from SRID 4326 to SRID 3011) by using ST_Transform. But ...
6
votes
3answers
773 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 ...
11
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3answers
4k 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.
4
votes
2answers
450 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 ...
3
votes
2answers
1k views

How to reproject from Michigan Georef to WGS84 in QGIS?

I am trying to reproject a michigan state land shapefile which is the NAD83/ Michigan Oblique Mercator EPSG:3078 to the WPG84 EPSG:4326 projection. However when i try to do this my map gets squished ...
9
votes
2answers
7k 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
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4answers
1k 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?
2
votes
1answer
2k views

Projecting shapefile with transformation using OGR in python

I want to change coordinate system of a shapefile from British National Grid to WGS84 (in order to be able to convert it to KML later on). To get the best results of projecting I would like to use ...
7
votes
1answer
3k 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 ...
5
votes
1answer
762 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
4answers
679 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 ...
4
votes
1answer
355 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 ...
3
votes
1answer
133 views

Debugging FMW memory usage near Group-based Transformers

I have a large FME FMW file which is using a lot of memory at runtime. I have been tasked with trying to find ways to reduce the memory footprint. Early on in the workbench there is (what I assume ...
2
votes
1answer
154 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 ...
2
votes
1answer
2k 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 4236. I first changed the SRID using: Select UpdateGeometrySRID('table', 'geomcolumn', 4326). I ...
2
votes
1answer
609 views

ArcObjects 10.1 .NET Convert Point from WGS1984 to OSGB1936

Please can someone help me convert a point in WGS1984 to OSGB1936, I have followed all the documentation (or so i think...) and yet have not made any headway into this problem. This is my code : Type ...
2
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2answers
1k views

How to perform transformations using ProjNet?

While writing some unit tests I thought it would be convenient/possible to use ProjNet to convert from EPSG:4326 into several other coordinate systems (3875,3395). I figured it would be as easy as ...
6
votes
1answer
298 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 ...
4
votes
2answers
144 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 ...
3
votes
1answer
70 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 ...
3
votes
2answers
567 views

Where is list of Geographic Transformations in ArcGIS, and their areas of applicability?

I have some data in Provisional South American Datum 1956, and I need to project it to Web Mercator with WGS84 as the datum. When I use the project tool in ArcGIS desktop, it requires a Geographic ...
3
votes
1answer
679 views

getting the specified geographic transformation, or at least the GCS, of a data frame

First, the TLDR digest: I'm getting a bogus value from dataFrame.geographicTransformations on some machines; how do I get the correct value as shown in the properties dialog? and/or Given a spatial ...
3
votes
1answer
663 views

Ordnance Survey data to WGS-84

Recently I have reprojected Ordnance Survey data from British National Grid (ORD SURV GB) to WGS-84 using ArcGIS 9.2. After re-projecting I have found some shift in the data. Can any body guide me ...
2
votes
1answer
147 views

Setting coordinate systems in QGIS: “transform error caught”

I'm learning how to use QGIS (v 1.8.0 "Lisboa") on Mac OS 10.6.8. My goal is to create a simple county map of Illinois using the base data shapefiles available from the Illinois Natural Resources ...
2
votes
3answers
2k views

Transform Data with Microsoft Spatial SQL

Is there a way to transform geographic data in SQL Server 2008 R2? Specifically, I want to take Lat/Long data and convert it to a State Plane coordinate system.
1
vote
1answer
53 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 ...
1
vote
1answer
108 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 ...
1
vote
1answer
98 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. ...
0
votes
2answers
654 views

Setting spatial reference for MapInfo tab-file

How can I change spatial reference for tab-file in MapInfo Professional?