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12

Note/Disclaimer: I work for Esri. Prior to ArcGIS for Desktop 10.1 service pack 1 (10.1.1), we loaded one geographic/datum transformation in ArcMap: NAD_1927_To_NAD_1983_NADCON (using the conus grid files). For 10.1.1, that was removed. All other transformations must be user-selected using the Transformations dialog. You can launch this dialog from the data ...


10

In order to get the coordinates in decimal degrees, the data needs to be reprojected to WGS84. import ogr, osr driver = ogr.GetDriverByName('ESRI Shapefile') shp = driver.Open('testpoint.shp', 0) lyr = shp.GetLayer() feat = lyr.GetNextFeature() geom = feat.GetGeometryRef() # Transform from Web Mercator to WGS84 sourceSR = lyr.GetSpatialRef() targetSR = ...


8

First, Proj4 uses what EPSG calls the "Position Vector" version of the 7 parameter method. It's possible that GeoTrans and Leica GeoOffice use the other version which EPSG called "Coordinate Frame". Both methods are equivalent, but the rotation matrices are different and the signs of the angular parameters have to be changed. Second, thank you for ...


8

I'm assuming that your input lat-long are based on the WGS84 datum. Making a point geometry under this assumption is as easy as using the ST_MakePoint() function: The problem with ST_MakePoint() is that the geometry that is created does not not have a spatial reference. We can set the spatial reference by using the ST_SetSRID() function. So the simplest ...


6

If you just want to convert coordinates from one CRS to another, the GDAL Tool cs2cs does what you want in an easy way. QGIS uses the same library in the background, so you will get the same results. GDAL uses the PROJ4 library to convert CRS and datums, so this is where to look up what is actually calculated. For converting NAD27 to NAD83 and WGS84, PROJ ...


6

The transformation failed for your case since the UpdateGeometrySRID command just changes the metadata, but does not transform coordinates. And when you attempt a transform from 4326->4326, no transform is done since the SRIDs are equal. If you have PostGIS 2.x with a table like this: CREATE TABLE my_table ( gid serial primary key, geom ...


6

Modern mathematics characterizes transformations in terms of the geometric properties that are preserved when the transformations are applied to features. A time-honored example is the set of Euclidean transformations of the plane: these are the ones that preserve all distances and (unoriented) angles. The study of this group of transformations is the ...


5

When talking about geographic locations, we usually say and use Lat-long. This has been codified in the ISO 6709 standard. When dealing with Cartesian coordinate geometry, we generally use X-Y. Many GIS systems, work with a Geographic Location as a special case of a 2 D coordinate point, where the X represents the longitude and Y represents the Latitude. ...


3

For proj4, the signs of the parameters have to be reversed. See this definition page: http://www.spatialreference.org/ref/epsg/62826405/prettywkt/ GEOGCS["Pointe Noire (deg)", DATUM["Congo 1960 Pointe Noire", SPHEROID["Clarke 1880 (IGN)",6378249.2,293.4660212936269, AUTHORITY["EPSG","7011"]], ...


3

The solution--- taken from the creator of RGeo himself, Daniel Azuma, in his rubyconf talk, which is hosted on youtube here: http://www.youtube.com/watch?v=QI0e2jkUbkk, his slides are here: http://speakerdeck.com/u/dazuma/p/getting-down-to-earth-geospatial-analysis-with-rails in db migration add_column :model_names, :shape, :spatial, :srid => 2264 in ...


2

I ended up solving this with the following code: mapHandler.gsvc.project([ geometry ], outSR, function(projectedPoints) { var polygonJSON = {"rings": projectedPoints[0].rings, "spatialReference": {"wkid": projectedPoints[0].spatialReference.wkid}}; var polygon = new esri.geometry.Polygon(polygonJSON); });


2

Does it reproject correctly in ArcMap? If so, right-click the layer and use export option. If that doesn't work, I would try using the Define Projection tool to reset the coordinate reference system information, then try using the Project Raster tool. Based on what you showed for the header, I think the tags are incomplete and that's why the projection ...


2

If you have ArcGIS 10.1, I would change the second transformation to "Datum_73_To_WGS_1984_2009_7par". It uses the same parameters as EPSG:5037, Datum 73 to ETRS89 (5). That transformation is listed has having an accuracy of 2m, but the accuracy should still be better than the one you're using. There's also a more accurate 7 parameter transformation for ...


2

In ArcGIS 9.3, the Project Tool doesn't support custom geographic transformations. We also hadn't added MGI 1901 yet. There is a tool, Create Custom Geographic Transformation, that allows you to create a custom geographic transformation which is saved in a .gtf file and can then be used in the Project Tool or in ArcMap. You have to be careful to match the ...


2

Your input values are in the projected coordinate reference system RD New, but you're using the well-known ID for the Amersfoort geographic coordinate reference system. Change the input spatial reference ID to 28992. Also switch the "Transform Forward" radio button to "True". The transformation is from Amersfoort to WGS 84, so you want to use it in its ...


2

osgeo.ogr can read all these formats: OGR Vector Formats osgeo.ogr and shapely support 3D: from osgeo import ogr point = ogr.Geometry(ogr.wkbPoint25D) point.AddPoint(5,4,4) point.GetZ() 4.0 from shapely.geometry import Point point1 = Point(5,4,4) point1.has_z True point1.z 4.0 you can change projections with osgeo.ogr: see Projecting shapefile with ...


2

You have entered the GCP coordinates in degrees, probably read from the imprinted degree grid. In that case, you have to set the CRS to EPSG:4283 (GDA94), which is the unprojected CRS for your EPSG:3112. EPSG:3112 has metres as units, not degrees. EDIT Another choice of doing the georeferencing is to create a vector grid in EPSG:4283. This is what ...


2

According to this (ArcMap automatically loads one geographic transformation. It's designed for the lower 48 states of the United States and converts between NAD 1927 and NAD 1983.) For datum transformations, you need to pick the transform yourself. This article goes into NAD83 <-> WGS84 choices. Projection changes can be done on the fly ...


2

ST_Transform(st_geomfromtext('POINT(" . addslashes($data[6]) . ")',29903), 27700) First you create your point in irish system with st_geomfromtext(..., 29903) and then you transform it to another system, in this case 27700. ( I assume that those srids are correct)


2

Convert the file to WGS84 gdalwarp in_test.vrt out_test.vrt -t_srs "+proj=longlat +ellps=WGS84" Calcualte the bbox with GDAL in Python import gdal ds = gdal.Open('out_test.vrt') cols = ds.RasterXSize rows = ds.RasterYSize geotransform = ds.GetGeoTransform() bb1 = originX = geotransform[0] bb4 = originY = geotransform[3] pixelWidth = geotransform[1] ...


2

There are different 2D adjustment methods because there are different sources of deformation. 1) deformations due to acquisition of an image by a remote sensor (central projection or push-broom) 2) deformations due to the representation of the Earth surface on a 2D plane 3) local errors My rule is to use the simplest method possible (the one that ...


2

Your transform goes from WGS84 to mercator. However, the coordinates of your bounds are not in WGS84 (a geographic coordinate system , with lat/long in degrees). Maybe your coordinates are already in mercator, or you should try to identify the correct coordinate system of your source before projecting the data.


2

I think you are almost there: If you post your workspace (or screenshot would be easier to follow) What I think you are missing is the BoundsExtractor for your polygon (rather than the vertices) http://docs.safe.com/fme/html/FME_Transformers/Default.htm#Transformers/boundsextractor.htm *2014 FME Desktop used here (looks different to 2013)


2

Sure, you should be able to go to Toolbox->Data Management->Projections and Transformations->Feature->Project. There, simply select your dataset and then click the button for output coordinate system, where you can browse to Projected Cordinate Systems->UTM->WGS 1984->Northern Hemisphere->WGS 1984 UTM Zone 33N.prj and press Open, Apply then OK. If you ...


2

the datum of BNG is GCS_OSGB_1936. When you project the data (or move to lat/long coordinate), you should also make sure that you set the correct datum transformation. Usually, any transform that you would choose in ArcGIS is precise enough for common mapping needs, but ArcGIS is not transforming datums by default in case of projection.


2

projections of vector datasets are not lossy in theory (if you don't have rounding errors, of course, which will depend on your software and your data storage precision). You should however be careful with projection of raster datasets, which are lossy because of the resampling. Now, if you change the datum (from one geographic coordinate system to ...


2

Some kinds of transformations are lossy. Transverse mercator for example can only be used for the visible half of the globe. The back side gets lost when you try to re-transform. Mercator only looses the poles, because it is accepted that the cylinder is unrolled in a world map. This is important if you have huge shapefiles, e.g. complete Russia or the ...


1

Look here and here. The first layer added defines the data frame’s coordinate system. This is true whether the data is projected or geographic. For example, if the first layer added contains a Lambert Conformal Conic projected coordinate system, all other layers will project on the fly to match this. Similarly, if the first layer added to the ...


1

You are trying to impose a North American Datum on South America data which does not work. PSAD stands for Provisional South American Datum developed in 1956. I would highly recommend you convert it to WGS 84 and assign the UTM zone if you have to do it for a particular country, region etc. This should resolve your issue. If you do not know which UTM ...



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