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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Geoserver Reprojection Results in Northerly Shift Compared to GDAL

I have data in a postgresql data store in EPSG:2163 and am displaying that using OpenLayers in EPSG:3857. This results in a ~25 km northerly shift when displayed either in QGIS or OpenLayers. To ...
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42 views

My class using ogr to calculate distance is returning incorrect results away from the equator

In an answer to this question ustroetz kindly provided some sample code for use of ogr to do lat/lon distance and point in polygon calculations. I've created a Python class based on his example to do ...
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42 views

Is there general Earth Projection in ArcGIS for Desktop?

I'm starting a new personal project and I need a little bit of helping on setting it up. First off I'm trying to determine the area of a rectangle that is 1 mile in width and the circumference of ...
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30 views

Hand-written coordinates from a Garmin NUVI

I've been asked to map point data that was collected in the field by manually writing down the coordinate from a Garmin NUVI 1490 LMT. They were put into a spreadsheet and sent my way which I was ...
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139 views

Which projection should I use to get my WMS service to work?

All of my shapefiles have exactly the same WKT. Using http://prj2epsg.org I have verified that EPSG:3059 has the same parameters as WKT definition of my shapefiles, so I'm using 3059 in my mapfile. ...
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34 views

Why this two datasets don't match?

I have a postGIS database in SRS 4326 (WGS84) with several Europe layers working well, but when I load a shapefile projected to the same SRS with QGIS, the layers don't match. To explain it better ...
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37 views

Problems with projections in QGIS 2.2 on a Windows Vista? [duplicate]

I use QGIS 2.2 on Windows 8, and the same QGIS 2.2 has been installed on a computer with Windows Vista. On the Windows 8 everything works just fine, but something is wrong on the Windows Vista. All ...
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26 views

calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
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25 views

Projecting polygon when calculating its area? [duplicate]

I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
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125 views

Azimuthal Equidistant - 40,000 Km range

I've been looking at making an azimuthal equidistant map. There are several web sites that offer to make one, based on my location, but they all have the same problem. They assume my antenna rotates ...
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29 views

How does Arc projecting data without spatial reference?

I have a raster file downloaded from here. When I load it into ArcMap, it says the data is missing spatial reference, and that it can be drawn in ArcMap but not projected. Nevertheless, using the ...
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66 views

How to create polygon that goes over +/-180 (dateline) in ArcMap?

I want to create a polygon feature that will go through the dateline (180 long.) in ArcMap. I am using WGS_1984_Web_Mercator_Auxiliary_Sphere (WKID: 3857) for my data frame and my polygonal feature ...
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2answers
73 views

ESRI projection to SRID?

I am looking at MapX and MapY coordinates. The docs say they are "truncated State Plane coordinates: NAD 1983 State Plane Louisiana South FIPS 1702 (US Feet)." I am trying to reproject into a common ...
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104 views

Help, I have 10,000+ .shp files covering 3 UTM zones with unknown projections

I was handed a ton of property files with no projections attached but was told they are all in UTM zone 21S. Well once I merged them all together and projected them I realized that the data covers 3 ...
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3answers
63 views

Geodesic measurements for short distances throughout US?

My ArcGIS experience has been limited to working on large-scale maps with planar projections. I'm moving to a project in which I want to calculate the distance between pro sports facilities throughout ...
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24 views

TileStache : Unknown geometry type in geoJSON file

I'm currently trying to set up a TilSstache server on Ubuntu 12.04 to serve some GeoJSON tiles from a shapefile/JSON file (administratives boundaries) for a web mapping project using the Leaflet ...
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37 views

Is it possible to render tile-based web mapping projects in any other projection than web mercator?

Web-mapping technology has to a large degree adopted the web-mercator projection as the standard projection for displaying geographic objects with interactive map-clients. This is due to many factors ...
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Add a raster specifying the projection in pyqgis

I would like add an raster but I want to specify the projection. If I do : qgis.utils.iface.addRasterLayer(url,layerName) QGIS ask me to specify the projection. I want to this with python. How I ...
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41 views

Scaling x,y coordinates in proj4

This question was asked before, but without answer. Let's say we have mercator map with given resolution (for simplicity in centimeters). Now let's get coordinates of (lat,lon) = (50, 15): $ proj ...
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37 views

Why are some layers saved with custom CRS while others use the appropriate EPSG code?

I have a number of .shp's that I have converted from EPSG 4148 to CPNO27. Some have come out perfectly and others revert to EPSG 1000007. I have checked and the only difference between the two is the ...
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14 views

Getting EPSG:4326 WKT data for use in Drupal Geofield [duplicate]

As I understand it, EPSG:3857 is measured in "meters" and EPSG:4326 uses latitude and longitude. In Drupal, geofield seems to want to store "EPSG:4326" data using the WKT widget -- even though the ...
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50 views

Projection problem? — OpenLayers, Drupal, and MapBox

I've installed OpenLayers in Drupal 7 and created a view that pulls geofield data for a "Geography" vocabulary (states, tribes, and U.S. jurisdictions) and shows points on a map that I'm storing on ...
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56 views

Convert decimal latitude/longitude bounding box to SRID 26910

I have a bounding box specified in decimal latitude/longitude, and need to convert this into a bounding box in the SRID 26910 coordinate system. I've never had to work with different GIS co-ordinate ...
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30 views

OpenLayers Projection and Datum Question

I had a conversation with a co worker that was asking about an OL map I am developing. She asked me what the 'projection' was and I said EPSG:4326. She didn't know what that means, so I said it's ...
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Is it safe to store coordinates on NFC tags always in one CRS and rely on conversion for others

I'm involved in NFC (Near Field Communication) standardization of a record structure for geographic point locations. That will allow to put coordinates on NFC memory tags which can be read with a ...
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58 views

Buffer is giving me a different distance [closed]

I'm using ArcGIS 10.1. When I Buffered I changed the environments to compare the two different projections. WyLAM is a statewide Lambert Conformal Conic projection used for Wyoming. State plane in ...
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28 views

Shorcut to apply selected shapefile projection to the data frame in arc gis

What is the shortcut to apply selected shapefile or the newly added data's projection to the data frame in arc gis, well not the traditional way of Dataframe--->Properties--->CS system "This could be ...
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31 views

Are ellipsoid and datum the same? [duplicate]

Are the datum and the ellipsoid the same? Please help me. What is a Datum? The Earth is shaped like a flattened sphere. This shape is called an ellipsoid. A datum is a model of the earth that is ...
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32 views

I want to reproject data from 0-360 to -180 - 180 [duplicate]

I've been downloading data from NOAA in a CRS that goes from 0-360. The rest of my data is in -180 to 180. What's the easiest way to reproject or shift the data in QGIS? It took 30 seconds in ArcMap, ...
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14 views

buffer in qgis from layer text delimited

I have a layer of polygons in British Columbia, Canada in WGS 84 which is fine. Later I created shapefile of three points (using decimals for lat and long) through the add shapefile as text delimited ...
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59 views

Why is it important to ensure that the shapefiles have a spatial reference system when created?

Why is it important to ensure that shapefiles have a spatial reference system when created?
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CartoDB - problem trying to add a geoserver WMS as a basemap and it says it doesn't contain supported projections (3857,900913)

I had suspected that the version of geoserver (2.0.2) did not support these 2 EPSG's . However, when I then look at the getcapabilities - I find that both EPSG's are present. ...
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52 views

How to automatically transform between base layer and vector layer in OpenLayers

I have a simple example on http://jsfiddle.net/29bsw/ I have a map with an OSM layer as base layer and an additional vector layer. The projection of the map is defined as EPSG:900913 and the ...
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1answer
58 views

Is it possible to use JTS for calculations on data in geographic coordinates?

I have some spatial data that has all of its coordinates as lat/lon pairs (with about 10 digits decimal precision), it's stored in a database as WGS84 data. Some of the data is represented as polygons ...
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35 views

gdal2tiles generates small picture inside 256x256 tile

I've used gdal2tiles for generating tiles in number of different polar projections and always experienced the same problem — strange small picture inside normal 256x256 png with the rest of space ...
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17 views

Adding a Z Unit [duplicate]

I'm struggling with the Z Unit conversion of some data. Both the NHD data and my DEM are in a GCS with Decimal Degrees. These data sets project perfectly on the fly, but after I adjust the Z Unit of ...
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42 views

Adjusting Z Units on a DEM

I am learning how to use ArcHydro and attempting to change the Z Units because I get a warning message saying the Spatial Reference Doesn't Match. The DEM was in Meters, and I adjusted the Z Unit to ...
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51 views

Calculate length of line across zones with at least m accuracy

I have created lines between multiple points that are across MGA 54 and 55S (EPSG 28355). I am trying to calculate the distance between points but different methods give different answers (~1km ...
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I have a WKT How can i put it to MAPINFOW.prj file [closed]

I have this WKT file: PROJCS["PRS92 / Philippines zone 3" ,GEOGCS["PRS92" ,DATUM["D_Phillipine_Reference_System_1992" ,SPHEROID["Clarke_1866",6378206.4,294.9786982138982]] ,PRIMEM["Greenwich",0] ...
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1answer
24 views

Determing which Which georeference system was used on an Ecuadorian Topo Baselayer

I'm creating a map in Western Ecuador, and am attempting to use a military topo baselayer for it. The map comes with UTM grid lines on it so georeferencing it was easy but I'm unsure of what ...
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117 views

Given a flight path given in latitudes and longitudes, how do I find another flight path that is parallel to the path given?

Given a flight route that is given in latitudes and longitudes, how do I find another route that is "parallel" to the route given (find a perpendicular line to each waypoint given)? I think the best ...
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1answer
33 views

Assign Projection to multiple shapefile

I have multiple shape files in a folder. I want to assign projection to all the files inside the folder at one go. In batch file i am able to assign projection to all the shapefiles, but i want to ...
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2answers
120 views

Why does Transverse Mercator projection have scale factor?

Why does the Transverse Mercator projection have a scale factor in ArcGIS and the standard Mercator projection not? In other words what is the difference between these two projections beside being a ...
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23 views

QGIS - unable to change projections [duplicate]

I am relatively new to QGIS (version! 2.0.1) and having trouble changing projections. No matter what I choose the view is the same. For example, in the attached screen shot I have chosen Alaska Albers ...
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35 views

Define Projection for an autocad transferred data

If I had a cadastral map on an Autocad file and i convert it to a dxf extension in order to open it in QGIS. I Added The Parcels borders and text in QGIS. Can you please list the steps which I should ...
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1answer
25 views

Equal (ish) areas Map Projection at the Tropics

What map projection (non-interrupted) preserves areas well for the entire tropical region? I am thinking of using a Cylindrical Equal Area or a sphere based version of a Cylindrical Equal Area or ...
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Convert land-based camera image pixel x,y to ground lat/long or x,y,z

I have a number of cameras at various known locations (x,y,z) and directions that are above ground about 20 feet pointed at different ground locations about 100 feet away from each camera, and whose ...
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1answer
42 views

How to find out projection code for the sid file?

I have a miami.sid file and miami.sdw and miami.sid.aux.xml files. How to find out the projection code? This question is similar to: I have a .sid image but can't figure out the CRS GDALInfo ...
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1answer
51 views

Using QGIS, features are suddenly placed 7.5 thousand kms off correct location

I've been counting an muskrat dens on lakes with aerial photos by creating a feature in a separate shapefile. I checked my progress after doing about 80 small lakes and suddenly, half of the lakes ...
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2answers
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Comparing projections of two datasets when SRID not available

Similar to this question: How to test if two GDAL datasets are in the same projection? However, the above does not cover cases where an SRID is not available. It can often be the case that an SRID is ...