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Questions tagged [reprojection-mathematics]

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0answers
20 views

Using GDALwarp for reprojecting netCDF file?

I am trying to re-project a netCDF file using the gdalwarp command. However, the gdalwarp is giving me a black output. Below is my code: import gdal import osr import netCDF4 from osgeo.gdalconst ...
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1answer
25 views

Converting from custom projection northing/easting coords to lat/long in decimal degrees

I've got a custom projection file that's applied to all data (per request of a client), and another team is requesting ids/coordinate pairs for assets. I tried ripping out X/Y off the point data, but ...
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0answers
37 views

Reprojection puzzle

Initially, my question was about strange results in area calculations in QGIS. I got bigger results for planimetric calculations - using area($geometry) - compared to ellipsoidal calculations - using $...
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0answers
40 views

Seeking Public API to get GPS satellite's position?

Is there any public availible API that allows you to retrieve the current coordinates of satellites such as GPS and Galileo? I've only found ways to get Satellites Ephemeries and calculate the ...
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0answers
15 views

resampling/resamplinh from MODIS to Landsat ; Google Earth Engine

Link to GEE I am resampling MODIS to Landsat Data, and my Goal is to get a Landsat like projected Image, but with fuzzy Borders of former MODIS pixels. What I do not want: I tried my Luck with a ...
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1answer
46 views

Creating Peirce quincuncial map in QGIS? [duplicate]

I would like to create a Peirce quincuncial projection of vector data using QGIS. A similar question was asked here several years ago, without apparent satisfactory answer. Someone offered a link to ...
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0answers
12 views

Computational Compatibility between different Projections, and it´s insurance in Google Earth Engine

My Goal is to extract Spatial Information for Usage in Tensorflow. I´ve got Spatial Information from Landsat(30m) and Modis(500m), if I want to extract this Information, do I need any form of ...
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0answers
14 views

Transformation from Sphere_Natural_Earth to WGS1984

I have a set of files that are stored in Tom Patterson's Natural Earth Projection, and I would like to convert them to WGS1984. This will require a transformation, but I can't locate one and don't ...
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31 views

Conversion between unknown map projections?

So I have two maps One that divides regions into small provinces (represented with "ID"s) Another showing which country controlled each part (shown with colours) I want to overlay them to see which ...
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0answers
27 views

Graphical error while reprojecting Shapefile with QGIS [duplicate]

I'm trying to retroject Natural Earth's Shapefile of the world (Admin 0 – Countries on this page: https://www.naturalearthdata.com/downloads/10m-cultural-vectors/). Here's the original Shapefile in ...
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44 views

Definition of custom coordinate system with Equator rotation?

I need to define cylindrical coordinate system in ArcGIS Desktop with numeric equator rotation. Pictures below show how Equator is rotated. Coordinates of points 1 and 2 are known. Is there a way ...
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24 views

What is this PostGIS query doing to measure the distance? How distance value is differed by the_geom and the_geom_webmercator

I dont know how the distance is differed based on WGS84 and Web Mercator. Sample: SELECT *, ST_Distance( the_geom::geography, CDB_LatLng(35.68879039, 139.74517892)::geography ) /...
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1answer
75 views

Warp a shapefile from transverse Mercator to Lambert projection

I'm quite a newbie in QGIS. I imported in QGIS a shapefile of a European country (as well as a TIFF representing the contour). These files are referenced in EPGS 3035. I would like to transform a ...
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0answers
39 views

Accurate area calculation for countries worldwide individually [closed]

I have polygons of countries with its administrative divisions, I would calculate the areas of each division in a country accurately. I got the bounding boxes for each country, then I divided its ...
2
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1answer
46 views

Relation between scale factor and standard meridians/parallels

Let's use transverse Mercator with a custom zone, with central meridian 30, the zone is 3 degrees wide at the equator, with a scale factor k=1, it means that the cylinder touching the spheroid along ...
3
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1answer
67 views

Vizualise different projections of a vector using QGIS

How to vizualise different map projection for a vector layer at once with QGIS, then export the two forms as Geographic WGS84 e.g. I have a shapefile for Europe, how to vizualise it in CRS Lambert ...
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0answers
54 views

Create custom projection for Shapefile, given specific target coordinates [duplicate]

I have a somewhat odd situtaion. A client has provided me with a Shapefile that has no projection information, along with an image of the map that it corresponds to. I have run some coordinates ...
0
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1answer
47 views

Failure to re-project SpatialPolygonsDataFrame to Equidistant Cylindrical in R (units problem?)

I am trying to re-project a shapefile to match the projection and units o Black Marble nightlights data (link below) which comes in a raster with Equidistant Cylindrical projection, units in meters. ...
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0answers
28 views

Reprojecting a SHP in QGIS to used it in ERDAS

I´m trying to created a AOI in ERDAS with a shapefile, but this shapefile had a projected system different to system that my image has, because of that I changed the projected system of the shp in ...
2
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1answer
322 views

Lebanese army projection + datum to WGS84

Most public offices in Lebanon give their data out as Esri shapefiles, with a strange non-standard projection, making it very difficult to use with any data from other sources, including any data in ...
1
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1answer
40 views

Help understanding coordinates

I am trying to use this lightning data set. https://www.ncei.noaa.gov/thredds/dodsC/lightning/countPerYear_Aggregation.ncml.html i do not understand the coordiante system which was used in generating ...
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0answers
44 views

Orthorectification on a DSM

I would like to orthorectify on the features (trees and buildings), noted that with may cause some stretching or tearing on the image due to the obliquity of the look angle. I'm only interested in top ...
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1answer
72 views

projectRaster() result does not have the same nrow and ncol, but has same resolution

I have a land use land cover (lulc) raster in WGS84 coordinate system shown below class : RasterLayer dimensions : 59575, 57541, 3428005075 (nrow, ncol, ncell) resolution : 0.000509, 0....
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1answer
83 views

writeRaster() not writing datum information

I am trying to reproject a raster to the USGS version of the Albers Equal Area Conic projection. Following this post, which talks about projecting vectors by adding the +datum=NAD83 and writing it out,...
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0answers
57 views

Projection of raster to sinusoidal projection

I have my definitive raster shown below. This raster has the projection as mentioned here class : RasterLayer dimensions : 7276, 8330, 60609080 (nrow, ncol, ncell) resolution : 463.3127, ...
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2answers
294 views

How to change the coordinate transformation function in Oracle?

I'm trying to reproject some data from one CRS to another (SRID:27493 to SRID:3763) using the SDO_CS.TRANSFORM function. The function works and returns no errors, but the coordinate transformation ...
2
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1answer
189 views

Reprojecting XYZ coordinates in Python whilst keeping Z coordinate constant

When doing a reprojection from a projected coordinate system (e.g. EPSG:28992) to a geographic coordinate system (e.g. EPSG:4326), the Z coordinate gets an offset of 45 meters. The Z coordinates of ...
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1answer
100 views

What does it mean to reproject a satellite image from utm (zone 13N) to wgs84?

I'm trying to understand some legacy code that processes landsat satellite images. Source images are in UTM and they are reprojected to WGS84. I'm a GIS noob but I understand that WGS84 is a datum for ...
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0answers
64 views

Improving reprojection accuracy

Main question: how can I improve the accuracy of my reprojection? I am combining my dataset to a previous one, and I have chosen a different CRS: the previous one is in WGS 84 (EPSG:4326) and mine is ...
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0answers
35 views

Distance between points not consistent

I have an Openlayers application where I can input a centre point, width and height in meters from which I can generate a bounding box to display on the map. The problem I'm having is calculating the ...
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2answers
210 views

Reproject SRID using DotSpatial

I'm nota GIS guy so I need some help. I need to reproject from one SRID to another. I'm trying to take global lat/longs (4326), reproject them to a local SRID (2336). This is basically the line of ...
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1answer
202 views

Project UTM Coordinates to three.js Coordinates With D3

I've been working on an application where I am building a 3d terrain, using three.js. The part I have working so far is building the 3d terrain mesh from standard 30m elevation data, and then draping ...
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0answers
48 views

What is causing ogr2ogr to fail to merge shapefiles without a reprojection?

Update 23-04-2018 The main issue has been solved, I (incorrectly) assumed all the files would share the same crs. This isn't the case and zones UTM 13N to 16N are used. So with no target crs for ...
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1answer
345 views

Finding correct extent of projection?

It is tricky to manage the extent of a coordinate system when that extent is not an aligned rectangle in another coordinate system. For example consider Thursday Island, located at: 142.2°, -10.2° (...
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3answers
63 views

Aligning Coordinate System?

I have some DEM files that use a coordinate system that doesn't align well with WGS84. I can align them through the data frame properties -> Coordinate Systems Transformation, where i type Only the x,...
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0answers
22 views

Is there such a thing as no projection? [duplicate]

I was reading an article that said when we display a map in WGS84 many people call it no projection. But most definitely when you see the map it has been distorted on a 2D surface. Which got me to ...
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0answers
46 views

AssetFinda Plugin projection issues in QGIS

I am currently trying to overlay raster and vector data in a common projection as the Asset data which is using NZGD:2000 EPSG:2193. I have an ecw aerial image that initially loads as a generated CRS. ...
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0answers
157 views

Postgis st_transform precision

I am checking effects of reprojecting planar coordinates from one CRS to another and back, keeping the same DATUM, and I was trying to determine the cause of the loss of precision. I know that ...
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0answers
267 views

Re-referencing raster in rotated coordinate system by “de-rotating” it

My Trying to define a "rotated regular grid" coordinate system in QGIS question about this got closed because there was already an answer to it, which I understand. I went to the answer in ...
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0answers
36 views

Relocate points added into a layer with different EPSG than the orthophoto layer using as reference

Thoundsans of points, representing singular trees in a region, were added manually into a shape layer with EPSG:23030, but it was done following visually the images from an orthophoto WMS layer with ...
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1answer
241 views

How can I use the authagraph projection in QGIS?

I have only been able to find this resource which reproduces the authagraph projection and it is compiled in C. Is there any way I can use this resource to make an authagraph projected map in QGIS? ...
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0answers
90 views

Azimuth on projected tile map

Here is a very specific problem : I have some mercator flight simulator maps I projected with real coordinates. However, due to game simplification, these maps are not oriented correctly and real ...
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1answer
41 views

Save GeoJSON file in GCS

I'm trying to make sure that my geojson file saved from QGIS is saved in a GCS with lat lng points. When I open my file I get coordinates like this which seems like my file is saved in nad83 as ...
4
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1answer
138 views

Which method is better for accurate area measurement?

Input : I have my original data in 4326. This data spans across the globe. This data is collected from DGPS so its accurate to 1 inch. The data is in geometry as geography is costly and functions are ...
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0answers
45 views

Equal area projection

In which projection I should project a polygon of a country to get the right area in the attribute table without a distortion? For example greenland
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1answer
446 views

Earth engine reproject: why does reprojecting a pixel at 30m scale gives me pixels with an area of ~550?

Trying to understand how reproject() in Google Earth Engine works. To find an example, I am using ee.Image.pixelArea(), which gives an image containing the area of each pixel in square meters. Now ...
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0answers
224 views

Need a projection like Azimuthal Equidistant (AEQD), but with polar coordinates

I have a geotiff in a simple latlon projection. I want to reproject its data on a plane tangential to Earth ellipsoid to make some further calculations. Just now I'm using aeqd projection for it, but ...
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0answers
90 views

Cartesian / Meters issue while making ellipses

I am trying to create an ellipse to be stored in my django project. I'm provided a lat, lon, major/minor in Nautical Miles, and an orientation in degrees. Between this post and the docs I've been able ...
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0answers
359 views

Calculate lat/long as percentage distance between two points (MSSQL)

I've loaded the US road shapes into MSSQL. I've determined the query to locate the segment of road for a specific address. The segment contains a "linestring" from a series of points. I'm trying to ...
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1answer
132 views

Bizarre Long, Lat coordinates…don't make sense at all

I've tried everything I can including all the possible projection transformations....these lng, lat's make no sense. Here is a sample coord with its disclosed mapping. The point is in British ...