Questions tagged [proj4js]
JavaScript library to transform coordinates.
101 questions
0 votes
0 answers
39 views
Adding image with given extent and given projection string to OpenLayers fails
Given an image, I have the following data provided: Citing/translating the docs: "The proj-string for the grid in the WGS84 earth model is:" +proj=stere +lat_0=90 +lat_ts=60 +lon_0=10 +a=...
- 156
0 votes
0 answers
125 views
Why does an error occur when using proj4 and proj4Leaflet?
I get an error when applying the coordinate system data Error: Invalid LatLng object: (NaN, NaN) at new D (leaflet.js:5:6566) at i.unproject (proj4leaflet.js:46:11) at i.pointToLatLng (...
- 41
-1 votes
1 answer
225 views
About CRS and map origin setting, What is their relation and math equation in leaflet.js via using proj4leaflet.js
I meet a problem about CRS function and map origin setting in leaflet. I use proj4leaflet.js as the basic CRS function, and then after setting the origin of crs and resolution, I can get the correct ...
- 123
-1 votes
1 answer
95 views
Custom project DXF data with metre units in JavaScript
I have a GeoJSON file with coordinates in metres in what I believe is the AutoCad World Coordinate System. (I converted from the DXF that was supplied to me, which was exported from AutoCad). The ...
- 5,800
1 vote
1 answer
828 views
Project React-Leaflet map in different projection
I am working on a college project that deals with MAPS. Our project is related to mapping the location of stadiums for the recent FIFA worldcup. The tileserver url provided to us is custom. When I use ...
0 votes
1 answer
127 views
British National Grid shapefile prj subtle differences change polygon accuracy
I'll preface this question with the statement I know very little about projection systems so this is coming from a position of total ignorance. I have two shapefiles. One is in England and one is in ...
- 437
1 vote
1 answer
696 views
Transforming point from EPSG:3844 to EPSG:3857 with proj4js
I'm having an issue transforming a point from EPSG:3844 to EPSG:3857 using Proj4JS. The transformation it performs seems off compared to the result given by PostGIS, pyproj, rgeo-proj4 or even epsg.io....
- 11
1 vote
0 answers
79 views
Different anchor point for EPSG:3857 coordinates [closed]
I have a couple of points in the EPSG:3857 CRS. These points are centered on 0, 0, which is the center of a map. I can convert these points to EPSG:4326 in Javascript with the proj4js library using ...
0 votes
0 answers
44 views
User Select CRS Tool
I am trying to create a tool which lets the user select a Coordinate Reference System from a list to project their data to. Are there any available libraries (preferably JS), datasets, or API's which ...
- 43
0 votes
1 answer
2k views
Wrapping maps using EPSG:4326 in Leaflet
I'm trying to use a tileserver in my leaflet app that encodes maps in EPSG:4326. I understand that I need to use Proj4Leaflet, and I'm setting up my CRS as follows: const crs = new Leaflet.Proj.CRS( ...
- 115
2 votes
0 answers
412 views
Extent of a proj4 string
I have a custom proj4 string in which my data is represented in Cartesian local coordinates. The example proj4 is below. +proj=tmerc +lat_0=44.155877943 +lon_0=141.655514872997 +k_0=1.000004976 +a=...
- 140
0 votes
0 answers
616 views
OpenLayers 6 change projection
Can someone please clarify how does the View object in OpenLayers 6 work as to achieve a projection toggle for a OSM and ImageWMS layers Map. I would love to understand how to change the projection of ...
- 119
2 votes
1 answer
232 views
OpenLayers Raster Reprojection to Mollweide cropped to oval
I'm trying to setup a Mollweide map, and only see a single projection of the world. Without the doubly projected areas in the corners of the map (see included images for clarification). Is there a ...
- 23
0 votes
0 answers
210 views
Moving WMS overlay independently to match baselayer in OpenLayers
I made a webgis that manages WMS layers in different projections with OpenLayers 4 and proj4js. Sometimes (e.g. for historical maps) the overlay is not perfectly aligned with baselayer and a need a ...
- 94
0 votes
2 answers
969 views
Given Web Mercator (EPSG:3857) coordinates, how to determine the relevant NAD83 local UTM Zone [duplicate]
I have a set of coordinates in epsg:3857: webmerc_coords = (-8956562.6 5368787.8) Is there a way to determine what the appropriate local NAD83 UTM projection should be for this point? I'm specifically ...
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