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8

You can put the WKT text into a text file, and run gdalsrsinfo on it: gdalsrsinfo test.txt >out.txt PROJ.4 : '+proj=lcc +lat_1=26.666667 +lat_2=29.333333 +lat_0=28.002808 +lon_0=84 +x_0=500000 +y_0=500000 +a=6377301.243 +b=6356100.230165384 +units=m +no_defs ' The ellipsoid parameters look very much like Kalianpur 1962, EPSG 4145: +proj=longlat ...


4

You could calculate ST_Area on a geography type. Since you have data with WGS84 (SRID=4326), you can add a simple geography cast, e.g. SELECT ST_Area(geom::geography) which will return area in m² on a curved surface (sphereoid by default). This should be pretty close to the true surface area, without requiring any projection. It would be interesting to ...


3

For Mercator, the cylinder is oriented along the North-South axes. There is thus a single orientation. If you want to adjust the deformation, you can play on the radius of the cylinder (hence affecting the scale). This projection works best near the equator, because this is where it fits the most to the ellipsoid. Using the position of the cut circle instead ...


2

Is this data sourced from India or Nepal? The EPSG Geodetic Parameter Dataset lists two transformations that apply to Nepal. It's difficult to recommend something in particular because the geographic coordinate reference system (datum) that you have just lists the ellipsoid information. tfm 6208 is actually for Nepal 1981 to WGS 1984. The ellipsoid is a ...


2

I suspect the issue relates to the very real difference existing between geometry objects, existing on a plane map surface, and geography objects, existing on a curved globe surface. It is always more accurate (but slower) to do calculations with geography types on a globe. Projecting features from a globe onto a plane always incurs distortion. Looking at ...


2

I just entered the coordinates into Google maps. If you change them to 35.205357, -111.59330 it puts you in the Flagstaff area. So The coordinates may have just had their decimal places in the wrong places or missing.


2

The scale is not a constant on map projections. For local map it is not an issue because the change in scale is so small that it is below the precision of the drawing, but for World map there can be huge difference when you change latitude (obviously, in a Mercator projection, the same distance near the pole is not equivalent to the distance near the ...


2

Anyone who wants to learn answer, there are 2 options for my problem; first one is changing map server or using a map proxy, second one is client map tile transformations. For further reading, https://groups.google.com/forum/#!topic/ol3-dev/YmBOj623jHo


2

I would prefer EPSG:3035. The ESRI codes might not be available on all platforms: EPSG:2163 has a different lon_0 leading to a distortion of the map:


2

You can shift the data into the correct position using these GDAL commands: gdal_translate -a_srs EPSG:4326 -a_ullr 0 0 360 -90 NETCDF:"sic_average_nclimate.nc":SIC_Change change360.tif gdalwarp -t_srs WGS84 change360.tif change180.tif -wo SOURCE_EXTRA=1000 --config CENTER_LONG 0 (with a little help by Frank Warmerdam: How to reproject raster from 0 360 ...


1

(This isn't an answer, but rather a process suggestion that is too long to be a comment) You could geo-reference it in QGIS using the GeoReferencer tool as you appear to be able to identify common points on both rasters. This would generate a GDAL script with a set of GCP points, and transformation parameters. You could add this script with a sample of ...


1

When you change the projection via the properties dialog, I don't believe you are re-projecting the data, you are asserting that the data is actually in the projection you are setting it to. That's why it's all screwed up when you try to use it. You need to use the "Project" tool in the Arc Toolbox. It's all explained here. Even though the article refers to ...


1

It is called the Equirectangular projection, plate caree or Geographic projection. This last name is nearly worthless in the age of Google. It is an ancient method associated with Ptolemy and very commonly used by nasa and other scientific endeavors where its size and shape distortions don't matter as much as ease. Just Google plate caree and click on ...


1

Displaying geographic coordinates (i.e.lat/long) as if they were 2D cartesian coordinates is similar to using the "Plate carrée" coordinate system (also called equirectangular). However, you will have a scale factor difference so it is not straightforward to put your points on top of the map. Therefore the suggestion to use a specific software is a good ...


1

I found the solution, here it is for it is helping anyone Following this answer http://gis.stackexchange.com/a/118818/42868 There is an unstable option for the ol.source.GeoJSON object, so adding it in this way made it work var source = new ol.source.GeoJSON({ url: 'geojson url', projection: 'EPSG:3857' });


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I think you just need to set the srs property of the layer layer.srs = "EPSG:4326" layer.native_crs = "EPSG:4326"


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Actually it would work as both are about ~~~~ the same latitiude but use the Euro version http://spatialreference.org/ref/esri/102013/


1

I finally figured it out: The real problem was that I stored the coordinates with latitude as the first value. That is the way Google Earth or Google Maps need the values, but it is WRONG for PostGIS. The coordinates need to be stored as (lon,lat). The way I did it, distances were calculated for the sea near Somalia. :P Now the distance calculations ...


1

The latitude value could be 35 20 53.57 while the longitude value could be -111 59 33. Or they could both be decimal degrees, with the appropriate insertion or change of position.


1

You are right, the way you want to reproject is wrong. Set Layer CRS does NOT reproject your data, but assignes the new CRS to unchanged coordinates, making the world 360x180 meters large. Save As... is the right way, but only on the original data, not on the corrupted data from the previous step. The world map from natural Earth includes the south pole. ...



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