A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane

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1answer
156 views

Aligning layers with questionable metadata in SW Ontario

After making my best efforts to read/try everything I can on this forum and elsewhere, I unfortunately have to contribute to the wide literature of "my layers aren't aligning" questions. I am working ...
3
votes
1answer
553 views

QGIS not interpreting Lambert Conformal Conic projection correctly

I'm a fairly new user of QGIS and I've run into an issue that I can't seem to solve on my own. I'm trying to work with the NRCan Atlas of Canada Waterbodies SHP file but I'm having an issues ...
1
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1answer
2k views

Pseudo-Mercator projection with Decimal Degrees?

Hope this isn't a duplicate, did some searching but none seemed quite the same. Projection I want: WGS84/Pseudo-mercator. Selected. Looks Great. Canvas units I want: Decimal Degress. Selected. ...
11
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2answers
2k views

How can I improve my Georeferencing results?

Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
1
vote
1answer
1k views

Reprojecting coordinates and geoJSON in leaflet

I have a Leaflet map in default projection and a wms layer also in default (web mercator) projection. I would like to add polylines and a geoJSON layer to my map, but the coordinates are in EPSG4326. ...
0
votes
1answer
130 views

how to correct merge rasters with different projections? [closed]

how to merge rasters with different projections with correct transforn? For example EPSG:32636 and EPSG:32637 if i do it with gdal_retile command, i have correct view for EPSG:32637 rasters and ...
1
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1answer
577 views

get data from WFS and present in using d3js - correct projection

I'm trying to get data for map of Poland. I found WFS service that provides GML files. It is located under: http://sdi.geoportal.gov.pl/wfs_prg/wfservice.aspx?request=getCapabilities&service=wfs ...
2
votes
3answers
1k views

How to calculate Polyline length in kilometres without changing projection from WGS84 (using ArcObjects)?

I have Road (polyline) feature class and I wish to find those roads whose length are greater than 500 kilometre. The feature class projection is in GCS_WGS_1984 and I do not want to change the ...
2
votes
1answer
253 views

Axis of rendered shape files not showing numbers that are latitude and longitude

I am using rgdal to render some shape file. The first is a set of building zones from NYC Open Data. The second is the NYC coast line from OSM. The Zone files seems to generally render an X axis ...
3
votes
2answers
209 views

Convert data to another Coordinate Reference System

Assuming I've a point like this : POINT (751318 9760879) This point is in EPSG:27700 coordinate reference system. How do I convert the point to display in a map with EPSG3857 coordinate ...
6
votes
1answer
492 views

How do I change an existing srs in QGis?

I am showing postgis data with srid 28992 (Amersfoort / RD New). But when I plot the geospatial data on a map (with openlayers plugin), the data is shown a hunderd meters off because the datum shift ...
0
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0answers
759 views

gdal python set projection of a raster - does not work

Gdal 1.9.2, ECW driver: ECW/ERDAS Compressed Wavelets (SDK 3.x) I am having problems with the script that supposed to set projection of the ECW to EPSG:27700, i.e. the British_National_Grid. Please ...
-1
votes
1answer
483 views

How to project geographic coordinates to cartesian with the least possible error? [closed]

I need to convert geographic coordinates (in decimal degrees) to cartesian with the least possible error? I searched a lot on the internet but it seems that the conversion is not exact. Could you ...
5
votes
1answer
1k views

Manipulating Azimuthal Equidistant Projections in QGIS

I have a shapefile of world countries that is projected as Azimuthal Equidistant with Chicago, USA as the center. I would like to change the projection such that Edinburgh, UK is the center. One would ...
2
votes
2answers
7k views

how to convert latitude, longitude projection from epsg:3857 to epsg:4326

I want to use geocode in our application. so that, I got Google geocoding API and could achieve with Google Maps. Problem is that I wanted to achieve the same with my own map which is having ...
1
vote
1answer
513 views

How to Extract Data from U.S. National Landcover Dataset (NLCD) dataset?

I am working with U.S. National Landcover Dataset (NLCD) to classify habitat type at more than 150 sites across the northeast U.S. The dataset is very large (15GB) so I cannot upload it here, but it ...
0
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0answers
370 views

Lambert conformal conic projection - Europa

I am trying to calculate map of Europa in Lambert projection. I am using formula from wikipedia (Lambert wiki), but calculation is verřy slow with comparison to Mercator. I know, there are sin, cos, ...
8
votes
2answers
432 views

Should point data be equidistant projected when using ArcGIS IDW spatial interpolation?

I am wondering if anyone can clarify whether point data should be projected to an equidistant projection when using ArcGIS IDW spatial interpolation? I am working on a dataset from Western North ...
10
votes
2answers
1k views

Waterman butterfly projection in Mapnik

Like the title says, how would someone configure Mapnik to use the Waterman butterfly projection ? Otherwise, what other tools would be able to render using this projection ?
20
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5answers
2k views

Simplifying geometries (generalization)

What are the recommended ways of simplifying geometries? Keeping in mind projections, and simplifying state geometries for example. I've heard about converting to an 'equi-distant' projection that ...
2
votes
1answer
282 views

How to synchronize the marker's rotation field with the angular distortion in the map projection

I'm Using QGIS 1.8.0 to plot a global dataset showing the positions of aircraft in flight. The data I have are .csv files with three columns: Latitude, Longitude, and angle of travel. I assign ...
9
votes
1answer
772 views

An example Tissot ellipse for an Equirectangular Projection?

I am trying to calculate distortion of an equirectangular projection via Tissot indicatrices. I have tried following the directions on this post (among other things) but it is beyond my understanding ...
7
votes
1answer
3k views

Leaflet and EPSG 4326 Projections

UPDATE: LEAFLET fixed support for EPSG 4326 (LL84) in the latest betas: https://github.com/Leaflet/Leaflet/issues/1207 Leaflet says it supports EPSG 4326 (Plate Carree, aka ll84) projections. I think ...
6
votes
2answers
649 views

How do I get the projection of an LAS file using liblas?

I am using the python api of liblas to read/write las files. I would like to get the spatial reference information of the las file using liblas, but have been unable to figure it out. Can anyone ...
4
votes
1answer
639 views

How to convert WGS84 to UTM when the study area covers 4 UTM Zones: 43- 46?

I'm working in ARCGIS 10.2, my area of interest falls in 4 UTM zones 43,44,45,46 equally distributed so i can't use the option of majority of area's UTM zone. Since i need to carryout varies analysis ...
5
votes
2answers
1k views

How do I specify a CRS for a fictional game map in QGIS?

I am about to start playing a steampunk RPG game called The Iron Realm, which uses a fictional world map. I have recently started using QGIS v1.7 and have no real experience with GIS sysstems. I have ...
4
votes
1answer
3k views

R - Plotting shapefile with geographical (raster) data

Over the last few days I have been trying to plot a shapefile over data loaded into a data.frame within R. It should be a view of radar precipitation with an overlay of the country borders from a ...
2
votes
2answers
420 views

Spatial Join of 2 line layers offset by minuscule amount

Let's say I have 2 line layers (green & red, in the image below) and I need to transfer attributes from one layer (red) to another (green) by doing a Spatial Join. The layers are identical, but ...
4
votes
2answers
147 views

towgs Definition for European Datum 1950

I am new to all things GIS so apologies for a basic questions. I am trying to specify the CRS of a climatic raster layer in R. It is an equal area projection based on Europe Equidistant Conic and the ...
3
votes
2answers
378 views

in python, srs.ExportToProj4() returns an empty string, why?

I have a shapefile with the following .prj file: ...
2
votes
2answers
392 views

Plotting a certain range in azimuthal projection using ggplot2

I would like to limit a map to a particular range of values (i.e. northern hemisphere) under an azimuthal or orthographic projection in ggplot2. When I set ylim, I receive an error message that ...
1
vote
1answer
378 views

Problem changing CRS to enable clip function

I have two layers, one point file and one polygon. The point file is in WGS 84 and polygon in NAD83-UTM10. The project CRS is NAD83-UTM10. They project fine with on-the-fly projection turned on. I ...
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votes
1answer
626 views

My wms vector data overlay on openlayer vmap work fine but on osm img is not rendering

i am try to overlay my India roads vector over an openlayer (http://vmap0.tiles.osgeo.org/wms/vmap0) vmap work fine.but i want to do the sam task over osm(open street map), i am trying many different ...
3
votes
2answers
789 views

Variation of algorithms to find point from another point with bearing and distance

There are several algorithms to calculate distance between two latitude/longitude points. Haversine Hubeny Lambert-Andoyer Vincenty's formulae for inverse problem But there are not so many ...
1
vote
2answers
335 views

Coordinates values change for ArcGIS

I have received thousands of location information like below. X= 10°52.579 Y= 078°38.473 I don't have idea in which format is this, please let me know what is the format of this location and ...
1
vote
1answer
745 views

TileStache + OpenLayers TMS - Tiles are rendered disorderly

I newly turned to TileStache to render Mapnik tiles because of the caching option. Before, I was using Mapnik python bindings only and it was working perfectly. Now that I use TileStache, the tiles ...
2
votes
1answer
230 views

Miller cylindrical projection - central meridian

I'm new to projections topics and I've got a question that may be silly, but I hadn't found answer so far. I'm trying to use Miller's cylindrical projection for converting osm lat/lon to x,y values. ...
2
votes
1answer
297 views

Viewshed analysis and coordinate systems ArcGIS 10.1

I am trying to run a viewshed analysis and I've downloaded DEM data from the UK ordnance survey (Landform-panorama). Since the data is in ASCII format I have created a seamless raster mosaic (and used ...
3
votes
1answer
37 views

Equidistant projection for northern Delaware

I'm just getting started on a long-term project involving northern Delaware. Most of my distances will use great circle distances from the lat/lon, but for a few applications I'll wind up using ...
2
votes
1answer
663 views

Qgis OSM and layer projection problem

I am using QGIS 2.1.0, and trying to import my vector layer(parcels) with OpenStreetMap layer. My vector layer (parcels) use EPSG 31277 coordinate system. This is the definition for EPSG 31277: ...
0
votes
1answer
161 views

Why are Bounding Coordinates not as expected? [closed]

I have a shapefile in GCS_WGS_1984 projection, but the bounding coordinates/Feature extent shows the wrong coordinates in the screenshot below. . I tried to change the projection, by deleting the ...
3
votes
1answer
229 views

How to get projected centroids in QGIS?

I am trying to get a centroid for several polygons on a global scale, in a way that it would correctly represent the common centre of all the polygons, taking Earth's curvature into account. The ...
0
votes
1answer
491 views

Why do points shift when reprojected from WGS84 to a state plane coordinate? [closed]

We have a Trimble unit we use to collect equipment. We collect the data in WGS84 and differentially correct it and then reproject it to a state plan coordinate system. The points always shift the ...
10
votes
2answers
1k views

Where did the polygons go after projecting a map in QGIS?

I'm fairly new at GIS know-how, but I've run into a problem with a projection of a world map. I have a shapefile of all countries I downloaded from Natural Earth. After projecting it into a ...
3
votes
1answer
212 views

What are the set of projections that can be accurately georeferenced using polynomial 2?

Background I'm starting with a map from the internet (Encyclopedia Britannica) and georeferencing it using QGIS 2.0.1, I get really accurate georeference solution using polynomial 2 transformation: ...
2
votes
1answer
739 views

Choosing correct proj4string in R for a set of points

I was given a set of points which I eventually will overlay with a polygon shapefile in R. The issue is that the person who provided me with the points did not give them to in long/lat coordinates but ...
2
votes
2answers
543 views

Data points Imported into QGIS are in the middle of ocean

I'm new to QGIS and tried importing some GTFS data in the CSV format (stops.txt). The project CRS, base map CRS and GTFS CRS have all been set to Google Mercator, but the points that are supposed to ...
2
votes
1answer
90 views

Change the projection at runtime (OpenLayers)

How do I change the projection on an existing Map object? I'd like to allow a user to switch between cylindrical (EPSG:4326) and custom-declared projections with the click of a button.
3
votes
2answers
382 views

Calculate distance in QGIS, wrong geographic projection?

I'm trying to do the following: I have 2 shapefiles, one containing all the public schools in NY, another one containing the hotspots in NY (both in points form). Now what I'm trying to do is ...
0
votes
2answers
939 views

How to transform a PostGIS bounding box?

I need to query the bounding box of a table (in WGS 84, srid 4326), and transform it to Web Mercator to be consumed by an OpenLayers map. Currently, I am using this to retrieve the bounding box: ...