# Questions tagged [reprojection-mathematics]

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### Mathematical rule to convert between degrees and centimeters based upon projection

I have some Tanzania drone imagery data in a local geographic projection EPSG:32737 that uses the unit of meters. Then I have other vector data that is in EPSG:4326 which is denominated in degrees. In ...
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### Reprojecting point data from EPSG:3078 to EPSG:4326

There are services to project from one coordinate system to another, GIS software packages that perform projections, but it is all black box, as far as I've been able to find. I want to see the ...
91 views

### Re-projecting a Raster in R to matching resolution, crs, and origin, but different extent

I have raster layers in a few different projections that I've loaded into R. I eventually plan on using the "merge" function of the raster package to bring these together as one surface, but to do ...
58 views

### Calculating direction for points (lon/lat) in a perfect circle (shape) north of equator?

I have perfect circles in lon/lat on a OpenLayers map. Near the Equator I locate each point on the circle using bearing-calculation for each point from circle-center. Meaning there are 360 bearings ...
33 views

### Lambert-Conic projection - GPS of corners

I have an 2D image in Lambert-Conic projection. I know the bounding box of coordinates, but I want to calculate the coordinates of image corners. They don't have to be the same as bounding box. How ...
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### Implementing “conformal mapping” in OpenLayers?

I want to preserve shape of objects, so how do I implement "conformal mapping" in openlayers 4.6.5? My current objects: I have several geoJSON objects (WGS84) around the globe in long/lat with a ...
100 views

### Converting GOES x,y coordinates from a 2D fixed grid into latitude and longitude

I am working with some GOES data in Python and I want to grab latitude/longitude coordinates from the data. GOES' stores their projection data in radians under x,y variables that are used to project ...
42 views

### Large offset between two identical vector layers

I want to have a dxf layer to overlay another layer. The dxf layer is already saved to a shapefile with the needed crs. The layer has a large offset and nothing happens when I set the crs to the ...
33 views

### Transform an azimuth measured in a given projection system to its value in a separate projection system

I have a set of polygons in which one of the attributes is azimuth. This azimuth was measured in ESPG:3310 (California Albers). I want to transform this measure to ESPG:4326 (WGS 84). I know the ...
185 views

### Points within polygons in different projections

I have a polygon and a point feature class in some projection. The points are contained within the polygons The points are always inside the polygons no matter the projection destination I'm ...
20 views

### VIIRS DNB daily data processing using ArcGIS Desktop?

The VIIRS-DNB daily data is availbale in .H5 format. How can I process the data to tiff/geotiff format? It is losing its projection when loaded into ArcMap 10.1 and even if exported into tiff ...
72 views

### How can I calculate degree of distortion on an Azimuthal Equidistant projection?

The Tissot's indicatrix of an Azimuthal Equidistant projection shows ellipses being stretched along latitudes. How can I calculate the degree (amount) of this distortion? That is, what is the ratio ...
43 views

### Whats your favorite map projection for [closed]

What is your a nice projection for the southern Atlantic? S.America & W. Africa? I'm looking to produce nice maps with little distortion on shapes. Leaning toward Lambert.
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### How to calculate OSM WGS84 Lat and Lon to meters in C++?

Summary I am converting OSM coordinates into X and Y values with accurate distances in meters between all points using c++. The calculations/code I am using is resulting in an incorrect ratio/scale ...
204 views

### Plotting lon/lat point (without manual conversion) on XY map using GeoPandas?

I am data scientist not experienced in GIS and need to do some simple map plotting of the Netherlands. Using Geopandas everything works out nice and dandy for my purposes however I am stuck on 1 ...
154 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 ...
44 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 ...
48 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 \$...
56 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 ...
42 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 ...
90 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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### 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 ...
16 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 ...
34 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 ...
28 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 ...
51 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 ...
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 ) /...
106 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 ...
49 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 ...
56 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 ...
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 ...
76 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 ...
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### 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. ...
33 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 ...
577 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 ...
41 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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### 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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### 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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### 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, ...
441 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 ...
283 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 ...
141 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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### 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 ...
42 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 ...
303 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 ...
273 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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### 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 ...
590 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° (...