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6

Your first idea is almost working. It needs a scaling factor between custom units and meters: Copy the definition of EPSG:2927 +proj=lcc +lat_1=47.33333333333334 +lat_2=45.83333333333334 +lat_0=45.33333333333334 +lon_0=-120.5 +x_0=500000.0001016001 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=us-ft +no_defs to clipboard, and paste it into a new ...


5

The linked kml file seems to contain valid degree coordiantes, but fails to open in QGIS. If you follow the source given in your link to http://www.ecaidata.org/dataset/spanish-and-mexican-land-grants-in-california, you can get a shapefile which misses its prj file. With some kind of educated guess, you will find that NAD27 / California Albers EPSG:3309 ...


4

I think the answer rests on what information about world rivers you want to communicate to your audience. For example, if you're trying to show a difference between the longest rivers in the world, you may want to use a projection with less area distortion. If you're trying to show where significant trade/resource rivers are, locational accuracy would be a ...


4

So there are two pieces to what someone might call a Coordinate System The first is a Geographic Coordinate System or GCS, which is what WGS84 falls under. The definition given by ESRI states that a GCS uses a three-dimensional spherical surface to define locations on the earth. Basically, a GCS is used to define your real world points on a 3 dimensional ...


3

So Albers Equal Area isn't just for use in the US. While it's mostly used here, you can change the center and parallels to reflect anywhere in the world. In this case, the Middle East. You can do that in d3 by changing the center when you're defining the projection. It would look something like this: var projection = d3.geo.albers() .rotate([*Rotation ...


3

I think you looked up the wrong way: https://www.openstreetmap.org/way/230844225 in Las Palmas de Gran Canaria. has the same way ID as the linkedGeodata.org dataset, but accidentally the same name as https://www.openstreetmap.org/way/32934574 in Cacares, Extremadura. And the node https://www.openstreetmap.org/node/337348441 still exists in the OSM ...


3

One of the ways to do this is to use the XY Event tool, which is used to create a point feature class from a table of x and y coordinates. You need to know what coordinate system the coordinates were recorded in as you will need this information to correctly locate the points. Coordinates in decimal degrees will need to be displayed with a Geographic ...


3

This answer will derive a simple, useful rule of thumb. Its analysis suggests that within any region of diameter a, the relative error when using a suitably well-chosen map projection to measure distances within that region will typically be a/(2R) or less, where R is the earth's radius. Since R is large (over 6 million meters or 4 thousand miles), ...


2

The correct answer would be when does it bothers you (depends on the application). If you want me to post curvature correction equations I will but generally the error introduced (in a survey) is small. For example in a 10km line the error would be around 6.8meters . But again when you are surveying an area you always apply curvature and refraction ...


2

A good starting place for GIS terminology is the GIS Dictionary hosted by Esri. Coordinate System A reference framework consisting of a set of points, lines, and/or surfaces, and a set of rules, used to define the positions of points in space in either two or three dimensions. The Cartesian coordinate system and the geographic coordinate system ...


2

With an unknown coordinate system you need to use trail an error... but in this case NAD 27 datums would probably fit the best. You can compare it with the kml file! In general, the normal way for a transformation would be... open the shape file it will open the "Coordinate Reference System Selector" select the coordinate systems (eg. EPSG 3309) and hit ...


2

You'll have to download the EPSG database and pull the information you want from it. They do provide PostgreSQL-compatible downloads. http://www.epsg.org/DownloadDataset


2

I'd use something like EPSG:3035 - it's a reasonable European projection that is equal area so it's suitable for most statistical mapping.


1

There are two principal datums used in South Africa. These include Hartebeesthoek94 and Cape. Hartebeesthoek94 Datum is the official geodetic datum for South Africa. The Cape datum is the older of the two is no longer used. This references the Clarke 1880 ellipsoid and it was developed by Sir Thomas Maclear and Sir David Gill in the later 19th - early ...


1

A UTM projection uses eastings and northings with units of metres, which look like the ones you have shown. To get Latitude and Longitude, you need to reproject it. In the ArcToolbox: Data Management Tools > Projections and Transformations > Feature > Project And for the Output Coordinate System, choose: Geographic Coordinate Systems > World > WGS ...


1

Since the given Spatial References in ArcGIS have got their own parameters for the vertical part, as far as I know there is no way of introducing vertical part by using the given factory codes or like sr = arcpy.SpatialReference(horizontal_wkid,vertical_wkid) that one may think it should work, but it is not. However, you can create your own spatial ...


1

Sorry. I was in a mistake: The current CRS is get by authid() method, not geographicCRSAuthId() On the other hand, I wanted to avoid the CRS Dialog when I load a vector layer from pyQGIS. Similar questions are been asked here and here . I have got the results setting QGIS like: Setting>Options>CRS ->Use CRS of project And I put my snippet of code to ...


1

Yes it’s possible to do that, all you need is to use project (data management) tool then to choose the WGS1984 but be careful to use the appropriate transformation to transform your points accurately


1

From the GeoTools Referencing FAQ - Can I just use Referencing without the rest of GeoTools? Yes, you will need to use the metadata module, and one of the epsg modules. Along with their dependencies such as units. Then all you need to do is: CoordinateReferenceSystem sourceCRS = CRS.decode("EPSG:4326"); MathTransform transform = ...


1

To clarify some things, you shouldn't need to convert a layer. QGIS should be able to transform them on-the-fly for visualization purposes. So you should be able to do the tests on-the-fly and once you find out the true EPSG of each layer then you can save the transformation into a file. Layer (a) cannot be in 4326 if it's boundaries are those you indicate ...


1

Make sure the file in qgis "lines up" with reality (check with openlayers plugin wether it matches with bing maps) Select your layer in qgis and in the "layer"-menu, go to "save as" and define wich CRS you want to convert the data to. You can even define what datatype you want your data in.


1

There is no projection problem here Shapely uses a cartesian plane system for computing geometries and the result is an unary_union of the original geometry (without any reprojection: "Shapely does not support coordinate system transformations. All operations on two or more features presume that the features exist in the same Cartesian plane", Shapely ...


1

There has been a lot of trouble with +omerc, +gamma and +no_uoff parameters in PROJ.4 and GDAL. Latest tickets are https://trac.osgeo.org/gdal/ticket/4910 https://trac.osgeo.org/gdal/ticket/5511 https://trac.osgeo.org/proj/ticket/114 I'm not sure if your GDAL and fiona versions are working with the latest releases of PROJ and GDAL. It seems that at ...


1

There are some interesting irregularities here. I'll try to generalize the answer, particularly by discussing the parameters that are zeroes in this definition but might not be in another XML-based coordinate reference system (CRS) definition. A colleague pointed out that usually XML has uses angle brackets for the attribute/value pairs. The geographic ...


1

The dataset use Pan-European mapping standard projection system - EPSG3035 If you are open to non-java tool and simplicity, you will be able to reproject the file to WGS84 using GDAL/OGR : http://www.gdal.org/, that way : ogr2ogr -f "ESRI Shapefile" path/to/NUTSV9_LEAC.shp NUTSV9_LEAC_wgs84.shp -s_srs EPSG:3035 -t_srs EPSG:4326


1

From mkennedy, the answer: "it's NAD 27 state plane zone, so already in US survey feet . . . I used US NGS programs to look up the state plane zone, then to test converting the xy points to lat/lon."


1

As you say you are using an image with GPS data in it the information is going to have been most likely stored in WGS84. Identify the part of the world you are working in, either by researching the source of the image and or imformation on the image. From there either project the GPS data using WGS84 as the datum into an appropriate UTM Zone that covers ...


1

Since this question never gets old, I built a site that does the Brute Force method. If you drag a zipped shp+shx onto the map it will map it in every coordinate system available in PostGIS. Assuming you know what "correct" looks like, you can zoom to that area and click on the polygon to get the .prj file from epsg.io.



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