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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2
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2answers
50 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 ? ...
5
votes
1answer
142 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 ...
0
votes
2answers
79 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 ...
0
votes
1answer
219 views

How to transform/convert Coordinate Reference System with Proj4 and php

Basically my question is: Can I combine the functions of proj4 with php in my server? For example, I would like to know if it is possible get data in WGS84 and transform in ETRS89. I need to get ...
1
vote
2answers
58 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 ...
3
votes
2answers
109 views

Determining closest representation of polygon as collection of points+radii

Have a bit of a tough question, which I realize there may not be an easy solution to. Figured what better place to ask. I'm attempting to transform a polygon into a series of arbitrary points with ...
1
vote
1answer
148 views

Vector affine transformation 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 ? ...
1
vote
1answer
40 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)) ...
0
votes
0answers
25 views

Offset WGS84 linestring based on pixel values

I would like to split up some roads based on their driving direction. For this, I need to offset the roads 2 pixels to the right, in the direction of the linestring. I have the coordinates in WGS84 ...
1
vote
0answers
30 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 ...
1
vote
1answer
54 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 ...
1
vote
0answers
25 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 ...
0
votes
2answers
49 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!
1
vote
1answer
41 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 ...
1
vote
2answers
60 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", ...
1
vote
1answer
48 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?
1
vote
1answer
92 views

ArcGis: Rotated grids and cell size

I am using ArcObjects, namely RasterGeometryProc, to apply rotation on grids. The transformation works fine. However, when looking at the grids properties in ArcGis, the cell sizes has changed. ...
3
votes
1answer
66 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 ...
2
votes
2answers
44 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 ...
0
votes
1answer
35 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 ...
1
vote
1answer
47 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
82 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 ...
2
votes
1answer
52 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 ...
2
votes
1answer
48 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 ...
2
votes
2answers
60 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 ...
0
votes
0answers
31 views

WGS 84 Transformation issues with ArcGIS and Global Mapper

I have rasters, need to be geo-referenced in WGS 84 datum with Lat/Log (degree). I have geo-referenced using Global Mapper, which we usually used to use, because of its user friendly. Got a vector ...
-1
votes
2answers
157 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().
0
votes
2answers
51 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 ...
0
votes
1answer
36 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 ...
0
votes
1answer
45 views

QGIS batch affine transformations

I have multiple polygon and line shapefiles on which I would like to apply a translation so I was wondering if it is possible to batch process them (maybe with graphic modeler ?) or do I have to ...
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 ...
3
votes
2answers
453 views

How to detect MGRS/UTM zone?

I posted a similar question on StackOverflow, but I thought I'd check here as well. I am developing an open-source library for converting between coordinate systems, and I've run into a wall. I want ...
0
votes
0answers
57 views

Is it possible to apply affine transformation (translation) to raster image?

Is it possible to move/translate a raster image in QGIS 2.2 (without using georeferencer) just like it can be done with a shapefile ? If not, alternatively can this be done with ArcGis?
2
votes
1answer
132 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 ...
0
votes
1answer
196 views

“Request contains a format not offered by the server.” Error when using CRS transformation with WMS in QGIS

When I try to load a WMS layer which has a WSG84 as a default projection and use a CRS transformation on it, it gives this error message: Request contains a format not offered by the server. The WMS ...
1
vote
0answers
36 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 ...
1
vote
2answers
62 views

How to figure out the SRID of a point by comparing it to another point with known SRID?

I have a set of store locations defined in the coordinate system of Bottincarto, which I need to display on Google Maps iOS. Here is an example of coordinates for Notre-Dame-de-Paris: 600926 ...
1
vote
1answer
235 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. ...
3
votes
2answers
69 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: ...
1
vote
1answer
60 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 ...
1
vote
1answer
98 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 ...
3
votes
1answer
69 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 ...
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 ...
0
votes
0answers
27 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 ...
1
vote
1answer
78 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 ...
2
votes
1answer
73 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 ...
2
votes
3answers
358 views

Datum transformations, do we use wgs84 as an intermediate common reference?

I was transforming some data the other day using the 7 param helmert transformation and it got me thinking. I have a set of transformation parameters, but these only describe the transformation from ...
2
votes
2answers
101 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 ...
2
votes
1answer
92 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 ...
3
votes
2answers
545 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 ...