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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Converting projected coordinates to google maps pixels

I have a single polygon in a local projection system. I would like to convert that polygon into an image that can be used as an overlay on google maps. I understand that it may be better to use ...
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1k views

Mapserver, TMS, Scales zoom levels and how to deal with all of it

I have a whole bunch of data in my db that I need to draw at different zoom levels using Mapserver. Everything uses a 4326 SRID. My (custom) client, will fetch the data using 20 TMS zoom levels and ...
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1answer
715 views

How can I programmatically project the Z value of a z-aware feature point, using ArcObjects in .NET/C#?

I discovered the following code leaves the Z coordinate of featurePt untouched: // if not WGS84 project it if (!SpatialRefsEqual(featureSpatialRef, srWgs84)) { // featurePt here is a Z-Aware ...
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3answers
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What is a good projection for the whole of China (with units in meters)?

I get some GPS results which lay in China with WGS84 coordinate system, and I need to choose a projection to reproject for. First I chooses the UTM projection, but I find the results lay in ...
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3answers
355 views

coordinate definitions from nyc.gov open data SpatialLocation field

The NYC Open Data website has a dataset of street events. The last column is called SpatialLocation, and is defined as a text field. An example is below. It is clearly two points on a physical map. ...
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789 views

Spherical Mercator projection invented by Google and not conformal?

I had some certitudes on the Google Spherical Mercator also known under EPSG code 900913 and 3857 before looking at this presentation, I was sure that this projection was in the Mercator family (so ...
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1answer
318 views

What coordinate system is this?

I just found a dataset of trees in San Francisco, but I'm unable to determine the system used for the coordinates. Here are some samples: 5998894.045593,2119007.035323 ...
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4answers
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OpenLayers transform EPSG 27700 coordinate to Google 900913

Community, I'm currelty capturing my mouse click event and trying to transform the coordinates into Long Lat. I need to get at the Long Lat as strings so I can build a url and throw it at Google ...
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2answers
183 views

Project house on WGS84

I have imported a DXF file of my house in QGIS. I also included an openstreetmap layer in WGS84 which also displays my house as a square. Naturally, my house from the DXF file is placed in the ocean ...
2
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1answer
97 views

Identifying coordinate system for Jersey

I'm trying to plot some X,Y coordinates which should be located on Jersey (the British dependency, not the state). The metadata that came with the points is as follows: Coordinate System: ...
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2answers
564 views

Suitable projection for a map of Japan

I'm making a map of Japan in QGIS which will span UTM zones 54 and a small part of zone 53 (central and North Honshu). I'm using Natural Earth raster and shape file datasets with some WSG84 based ...
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2answers
1k views

OGR Projection transformation error

I am trying to convert shapefile that was created by FME in EPSG:900913 to EPSG:3857 (I know its the same definition) with OGR in a script. datasource = ogr.Open(os.path.join(dirname,shapefileName)) ...
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2answers
1k views

Converting google map api coordinates into meters

How would I go about converting the results of my map bounding box into meters within javascript? For example, if I have the coordinates 51.52366625446907, -0.07467269897460938 decimal degrees, can I ...
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2answers
56 views

Best Projection for Getis Ord Gi* Statistic Analysis

I am about to calculate the Getis Ord Gi* statistic for some rasters whose extents are global. In choosing a projection, do I want to preserve distance (e.g. equidistant) to obtain accurate ...
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2answers
97 views

Choosing country projections

Anyone know of a good reference (either pay or open-web) that details recommended country projections?
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3answers
280 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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1answer
114 views

How can I get the ellipsoidal values for length and area using spatialite?

I have spatialite geometry data stored in a spatialite database in WGS 84 (EPSG 4328) format: SELECT Srid(geometry) FROM shape_layer; > 4326 When geometry is being returned as text, it is ...
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2answers
4k 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 ...
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2answers
169 views

Set projection/CRS in map and shapefile to produce buffer

I simply want to create a buffer of a specific size, around a single point. When I create a buffer it uses degrees/ or radians, or whatever, and the buffer is created that covers the whole screen. I ...
2
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3answers
467 views

What is the projection of an Android Location class instance?

What is the projection of a Location object returned from the LocationClient by a class implementing the LocationListener interface with a fused provider in the Google Play Services SDK? For example, ...
2
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1answer
60 views

What is the purpose of having a separate Layer property for sphericalMercator?

The Beginner's Guide to OpenLayers 2.10 says the following: sphericalMercator {Boolean} This property determines if the map should behave as a Mercator-projected map. Setting this to true ...
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2answers
624 views

LonLat Points to Grid of Polygons in PostGIS

I'm going to preface this with it's my first time using PostGIS. I'm starting out with a 5 km x 5 km grid cell in which I know the center point lon/lat (SRID=4326). I'm trying to create a polygon for ...
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3answers
2k views

Why are the tile coordinates different in Google maps and Google earth?

I have a .NET application that typically uses the standard Google Maps JavaScript API V2. Within this application I am using a GTileLayerOverlay to add my own custom dynamic tile layer. function ...
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3answers
87 views

Plotting Netcdf data. How to get right projection?

Maybe it's very easy for someone to fix, but I'a a new one in R, so I really need help. I/m trying to plot data containing lat, lon and variable (nmf2). The grid isn't a regular one, so there are some ...
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2answers
53 views

Help projecting Austria data with QGIS

I'm trying to reproject this dataset from Austria Statistik Geodata. Data comes in "MGI_Austria_Lambert", and I'm trying to reproject to WGS84 What I'm doing is Saving layer as... and selecting ...
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2answers
303 views

How to compute area for polygons in an EPSG:4326 shapefile?

I have a shapefile covering the whole globe, in EPSG:4326 (geodetic WGS84). I would need to compute the polygons areas in a metric such as km2. How can I do that in QGIS or with gdal/ogr and having a ...
2
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2answers
2k views

What Spatial Reference System do I store Google Map's Lat/Lng in

I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and Openstreetmap and its services like the Geocoder/Nominatim. I'm ...
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2answers
406 views

How to avoid exceeding latitude and longitude limits, when importing a .csv file?

I am currently working with a project with "on the fly"-projection (WGS 84 / UTM zone 32U). Now I want to import a csv. file with points, which have a longitude and latitude using the "Add Delimited ...
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3answers
480 views

C++ coordinate class that automates projection?

Can anyone point me to a C++ class for representing coordinates that automatically handles projection transforms? What I'm thinking of is something that would allow me to create vars that incorporate ...
2
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2answers
371 views

How to shift the Map a little bit?

I'm having trouble with two maps, both UTM33N/WGS84. They should be exactly on top of each other but there is a slight shift between them of probably a few hundred meters or so. I Tried to adjust ...
2
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2answers
396 views

Shapefile CRS changed after exporting from QGIS. Are they equivalent?

I added a shapefile as a vector layer in qGIS 1.7 so that I could join in additional attribute data (not geodata) from another DBF file. The Shapefile that I added has this CRS (as far as I can tell ...
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1answer
94 views

Why my Shapefile is not loaded into OpenLayers?

This is my website for test: http://www.cv.nctu.edu.tw/tonywang/shapefile-js-openlayers/ol_simple.html I want to put my Shapefile in OpenLayers. I found an example at ...
2
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1answer
113 views

Displaying map tiles from GeoPackage

Is it possible to translate tile requests from a mapping engine wanting Google Map style tiles into tile requests from a geopackage file? If not, where can I find information about how to create a ...
2
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1answer
146 views

Why is this .prj file causing the shapefile to render in meters instead degrees?

So I've got a shapefile that has polygons of countries, with coordinates in decimal degrees: Country (String) = Algeria POLYGON ((6.928073999999953 36.88360652, 6.949973999999969 ...
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3answers
307 views

Problem with Geometry SRID in PostGIS

I ceated my table (borne) in PostGIS id_borne serial NOT NULL, num_borne character varying, shape_borne geometry I successfully changed the SRID of my table using select ...
2
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2answers
166 views

Wrong projection high quality shapefile for the coastline of Helsinki region (Finland)

I did some spatial interpolations in R and I need a support for those. Looking for shapefiles online the best I could find was and it looks really horrible, the same area in ggplot looks like . I ...
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3answers
548 views

How to find and apply reprojection parameters?

I have a data set in one projection, and a shapefile in another, and I am trying to combine the two. I am using Python. I apologize for posting a "help me transform coordinates" question on this site ...
2
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1answer
112 views

Using ogrinfo to list all projection source of a database [closed]

I have to reproject all the layers from a database, but some of them are undefined and some are defined in a wrong projection. I would like to sort all those layers in a text file with their source ...
2
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1answer
169 views

Stumped on python looping and data dictionaries

I have been stumped getting my python code to work for a while now. I've been using python for the last several years on and off for simple things, but I am far from an expert in python. I am trying ...
2
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1answer
202 views

Does the Load Data function in ArcCatalog automatically re-project the data?

If I have a feature class within a dataset in one coordinate system and using the Load Data function, load that data into a feature class of a different dataset that's in a different coordinate system ...
2
votes
2answers
109 views

How to reproject all featureclasses in a database to another database?

I am very new to arcpy and have ArcGIS 10.0 I would like to make a script where I would only have to change two variables in a script (database_input and database_output) so that I can reproject all ...
2
votes
1answer
221 views

If I've given two different layers the same CRS, why won't they overlay one another?

I have a "towns" and "state" shapefile for Massachusetts as two separate vector layers in QGIS. I've set the project coordinate system to WGS 84 at the bottom of the screen (next to the "coordinate" ...
2
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2answers
276 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
2answers
750 views

What is the SRS code for Lambert Conformal Conic projection and GCS Everest Definition 1962?

I have a shapefile with Geographic Coordinate System is "GCS_Everest Definition 1962" and the Projected Coordinate System is "Lambert_Conformal_Conic". I want to add this shapefile in Geoserver. But I ...
2
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1answer
2k views

Import GPX to QGIS with WGS84 [closed]

When loading a GPX-File in QGIS it is not referenced on WSG84. It´s shown with wrong coordinates. Settings are WSG84.
2
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1answer
994 views

Projection ETRS89 (Ellipsoid: GRS80) 6-Degree Zone 33 to UTM33N - WGS84

Hi I'm having trouble to reproject a shape file in Qgis. The projection is supposed to be "ETRS89 (Ellipsoid: GRS80) 6-Degree Zone 33" and I would like to project it to UTM33N - WGS84 (EPSG 32633). ...
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2answers
5k views

How to create custom coordinate system in ArcGIS Desktop?

I have a series of control points with xy coordinates in both NAD83 UTM and in a local grid. How can I go about creating a new projection file in ArcGIS 10 for the local grid?
2
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1answer
855 views

Overlapping map tiles with mapnik's generate_tiles.py script

I'm trying to generate map tiles using the mapnik's generate_tiles.py script, but the resulting tiles are overlapped. Example The tiles have the following directory structure: ...
2
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2answers
609 views

Is it possible to reproject KML using ESRI's Javascript API?

Specifically into NAD83. Google tells me that KML only supports WGS84, but I can't seem to find much info on being able to reproject KML using ESRI's Javascript API. Basically, I've got this base ...
2
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2answers
908 views

albers projection to Lat, Lon

Thanks in advance for helping me with my issue. This GIS stuff is using parts of my brain that have remained idle since high school, and some parts are working faster than others. I have land data ...