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0
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1answer
23 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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0answers
34 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,...
1
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0answers
20 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, ...
1
vote
1answer
24 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 ...
1
vote
1answer
28 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 ...
0
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0answers
12 views

Mismatching after export from Google Earth Engine to ArcGIS

I want to study three datasets together: SRTM, MODIS, and PRISM. When I import them in Google Earth Engine and show them on the screen, everything is fine and all the edges match perfectly (first ...
1
vote
1answer
47 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 ...
1
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0answers
41 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 ...
1
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0answers
17 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 ...
2
votes
2answers
55 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 ...
0
votes
1answer
86 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 ...
1
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0answers
46 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 ...
0
votes
1answer
71 views

Where to find correct extent of a 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° (...
2
votes
3answers
52 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,...
0
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0answers
21 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 ...
1
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0answers
23 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. ...
1
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0answers
90 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 ...
4
votes
0answers
226 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 ...
1
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0answers
32 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 ...
0
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0answers
37 views

Transformation from unknown projected system to WGS84 from known data points in qgis

I have a set of points with conventional (X,Y), supposedly projected coordinates (easting and northing). These X,Y data are just values in mm, measured on a paper map from some arbitrary origin point. ...
1
vote
1answer
132 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? ...
0
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0answers
36 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 ...
0
votes
1answer
34 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 ...
0
votes
0answers
32 views

Batch Project/Transform Rasterfile [duplicate]

I get the following message after trying to Project/Transform Rasterfile in Batch-Modus. I dont know what to do! TypeError: native Qt signal is not callable Following the Error-Message and the ...
4
votes
1answer
101 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 ...
0
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0answers
21 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
2
votes
1answer
198 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 ...
1
vote
0answers
153 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 ...
1
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0answers
53 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 ...
3
votes
0answers
252 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 ...
0
votes
1answer
122 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 ...
2
votes
1answer
581 views

Convert features from EPSG:3857 to EPSG:4326 projection not working OpenLayers 4?

I have a simple task to do, supposedly OL4 and format.GEOJson.readfeatures should do that automatically. But it doesn't. Remembering that is a FeatureCollection and has CRS set. I have a map with ...
14
votes
1answer
1k views

Understanding reprojection?

One thing that I can't quite get my head around is Reprojection. It comes up a lot in questions on Stack Exchange, and there are plenty of How to questions and answers about specific issues using ...
3
votes
1answer
561 views

Calculating the earth radius at latitude

This is an extension to this question: How do you compute the earth's radius at a given geodetic latitude? and to the Wikipedia page: https://en.wikipedia.org/wiki/Earth_radius#Geocentric_radius ...
3
votes
1answer
304 views

Create a polygon using GDAL to calculate the points

I wish to create a polygon that looks like this (it's a tree and a root scan): I have a file containing positions where readings have been taken, and I have the centre point and the projection. So, ...
2
votes
0answers
31 views

Working with intersecting polar grids

I'm having some trouble figuring out the best way handle some GIS data. I want to analyze pollution from specific sites at specific points. I have a list of sites I'm interested in all across the ...
1
vote
1answer
246 views

How do I get utm data converted into wgs84 all within Python27?

How do I get utm data converted into wgs84 all within Python27? Does anyone know how to import the QGIS Lyon 'reproject' tool I to Python27? I have a Python script that writes utm Into a text file ...
1
vote
1answer
126 views

How to describe a MODIS Tile's distortion

When looking at the MODIS grid [1] and compare it to how the sinusoidal projection is distorted, I wonder how to both practically and formally describe the distortion factor for each MODIS grid tile. ...
0
votes
1answer
228 views

Re-projecting ground control points of similar images (Georeferencing in QGIS)

I have several maps to digitize. The base maps were Canadian NTS map sheets, all for more or less the same region. The useful information has been traced on top with handwritten markings. The maps ...
0
votes
1answer
644 views

How to know what value use to convert meter in degree using Google Maps info [duplicate]

I am trying to create a mathematical formula to convert meters to decimal degrees. Reading this article Decimal Degrees, I thought this generic formula: x = (Value_in_meter * 0.00001)/1.1132 But I ...
6
votes
3answers
8k views

What is the formula for calculating world coordinates for a given LatLng in Google maps?

I want to calculate a given LatLng to the world coordinate . I know I can use the internal projection of Google maps like this: var map=new google.maps.Map(...); map.getProjection()....
1
vote
0answers
38 views

Translating lat/lon coordinate on rotated/scaled maps

I need to indicate a lat/lon coordinate in an old map like this: http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~3017~90020003:Topographical-Map-Of-The-City-and-C Projected on Google Maps: ...
7
votes
4answers
154 views

Selected Literature on coordinate transformations?

I am looking to hone my skills in the theory and the mathematicas involving the projections systems, projection transformations ( from xy to uv, φλ and vice versa). Can you share the books/pdfs/...
7
votes
1answer
796 views

Determining Natural Origin for a GeoTIFF file (Lambert Conic)

I am trying to display an existing GeoTIFF file (from the FAA WAC set) in an application that requires the GeoTIFF NaturalOriginLongitude tag (FalconView 5.1.1). There are some older files in that set ...
3
votes
2answers
1k views

Overlaying layers with different projections on Android

Hello, I'm trying to show a map on Android. I'm using two map providers and am having trouble when converting geo point(lat/lon) to point in my viewport(x/y in pixels). 1) the first map provider used ...
10
votes
1answer
480 views

Learning about Reprojection?

I would like to expand my knowledge coordinate systems, projections and reprojecting data, with a view of writing a reprojection engine. Could you provide me with some resources (books, websites, ...