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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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 ...
3
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2answers
235 views

What projection is this in GDAL classification

I need to re-project a PNG from a given projection to the Google maps projection. I have a grid of the source projection, looks like a Mercator projection. What is the exact name of this projection in ...
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2answers
832 views

How to transform data points from WGS84 to NAD27?

Preface: I have a set of lat and long data points from Google Maps, which I believe are in WGS84. My project data is in NAD27(BLM14). These points are in West Texas, where NAD27 differs from WGS84 by ...
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3answers
297 views

How to reproject to other projections than WGS84 or Webmercator?

I have an OpenLayers map with a vector layer to add points on. I'm using Google Maps as the base layer. After the point is added, I need to store the data in my database as lat/long and x/y. Can I ...
3
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2answers
2k views

How do I get the distance meter value between two geometries in PostGIS?

I have a simple question about calculating distances in PostGIS. I would like to get the distance between two geometries. I am using this sid : 4269 in meters what i am doing now is this : ...
3
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1answer
286 views

How would I go about re-projecting the Blue Marble raster maps into a robinson projection using free tools?

I would like to convert the NASA Blue Marble maps into a robinson projection.
3
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1answer
2k views

OpenLayers doesn't show an overlay with a different SRS than the base layer

I need to add an overlay layer that uses EPSG:4326 to a map with a base layer that uses EPSG:32628. Every time I add the overlay OpenLayers automatically switches the SRS param of the overlay to ...
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3answers
328 views

Is there a projection issue with the NRC Canada Atlas hydrology data?

I have been using the Natural Resources Canada (NRC) data for various generalized maps but it is not until now when i overlaid higher resolution features obtained from the provincial government ...
3
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1answer
72 views

Is there any Google Maps-like zoomable world map, but with an equal-area projection?

Whenever I look at Google Maps at a global or polar area, the projection hurts. Is there any web service with a zoomable world map, that uses an equal-area projection — preferably pseudorectangular ...
3
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1answer
104 views

Problem with projection in layer

I'm having problems with visualizing a layer which is in EPSG:4326 Apparently the geometry looks perfect, but I don't know why, it's not in real coordinates. I have projected it to 4326 with QGIS, ...
3
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1answer
201 views

D3 to match this QGIS projection?

I have a map of Finland in QGIS, which says CRS = ETRS89 / ETRS-TM35 (Authority ID = EPSG:3047). I'm trying to show the map with D3, and can't quite match the borders/projection. The black one is ...
3
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1answer
170 views

What's the projection of this albanian military map?

I've received some very useful maps of Albania for my work (scale 1:25000) and I would like to georeference them in order to put them together to one Map for my destined regions. Unfortunately I ...
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1answer
77 views

What is displayed when I am using a geographic CRS for my project

I understand that each geographical dataset has a CRS, and that in order to overlay them, you need to either make sure that all datasets use the same CRS, or re-project some of them (or use on-the-fly ...
3
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2answers
1k views

German coordinate system from Lat/Long

I have WGS latitude and longitude for data points near Munich and I'd like to use a grid-type coordinate system, like the Ordnance Survey grids in Ireland or the UK. What coordinate system do you ...
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2answers
165 views

Can you search WMS services for a particular projection?

Is there an interface or website to search public WMS services for location/projection?
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4answers
493 views

Determine Projection

I was given a shapefile at work with the information that it is in Lambert Azimuth Equal Area (LAEA) projection (EPSG 9820). After some research on the web, I found out that EPSG 9820 is a generic ...
3
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2answers
3k views

How to read projection information from .dwg file

I have got an Audocad .dwg file which is based on some location of sweden. But i dont know what is the internal projection of this file? how i get projection information from this .dwg file. Actually ...
3
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3answers
11k views

Calculate projected area of polygons with field calculator in ArcMap 10

I've got a polygon featurelayer in arcmap. The coordinate system of the featurelayer's featureclass is web mercator. The dataframe of the map uses an equal-area projected coordinate system. I've ...
3
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2answers
848 views

Which ESRI defined geographic transformation do I need to use to convert my “ NAD83 Northern Virginia” data into WGS 1984 Web Mercator?

My title pretty much tells it all.. I have a number of datasets in which I want to batch project from NAD83 Northern Virginia Datum into the correct Web Mercator projection.. When I do a straight ...
3
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2answers
116 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 ...
3
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2answers
112 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 ...
3
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1answer
160 views

Coordinate systems and bearings

Ok so I've got a noodle scratcher and want some input before I open my mouth to my higher-ups. I recieved a new boundary description from a surveyor that uses metes and bounds in the form of bearings ...
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2answers
190 views

Geostationary Satellite Projection

What is the equation needed for forward and inverse transformation of Geostationary Satellite projection.?. How to convert it to Geodetic and vice versa. Geostationary satellite projection is ...
3
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2answers
200 views

Is there a world projection that looks like a 3D globe?

I would like to try and show data such that it appears as if it was on google earth. For example, in this case, the view of the earth is circular-like and the data shown curves around. Are there any ...
3
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1answer
210 views

How to get spatial reference of a shapefile using python?

I always use arcpy.GetParameterAsText to get the spatial reference from the user. There should be a way to decide what is the spatial reference of a shapefile but I can't find it. Something like ...
3
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1answer
93 views

How to test if two GDAL datasets are in the same projection?

I'm attemping to write a funciton to test if a list of datasets are in the same projection. Naively, I thought I could test the text of WKTs, but that does not work in the following case: ...
3
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1answer
231 views

Why are two incompatible projections used together in OpenLayers? [duplicate]

While going through the examples in OpenLayers, I notice several examples with the following code: map = new OpenLayers.Map('map_element',{ ... units: 'm', projection: new ...
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1answer
297 views

Is a WMS map always a constant scale?

If I get a map back from a WMS server is the scale always constant over them map regardless of the reference system? So if I have a map which is 100 pixels wide, will the point at 50 pixels always ...
3
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1answer
131 views

QGIS display does not reflect projection

I have slight experience with ArcGIS, but am new to QGIS. I'm trying to set the projection of my map, and I understand that this is done by altering the CRS (coordinate reference system) of each ...
3
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1answer
78 views

Should states/provinces be stored as geographic or geometric data types?

While reading the GeoDjango documentation, they advise using geometric rather than the geographic data type when storing values that are on a continental scale. The Canadian province of Ontario, for ...
3
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2answers
952 views

Get Lon Lat values from a GEOGRAPHY data type in PostGIS

After storing lon lat values as a GEOGRAPHY data type, how do I retrieve the individual lat lon values? Failed attempt: SELECT id, geog, ST_X(geog), ST_Y(geog) FROM locations; Error: No function ...
3
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1answer
154 views

how can I know which projection has this data?

I have data in an unknown projection to me. I open it in QGIS and I see that the shapes are ok, but I need to identify the projection in order to merge this data with other stuff. The points look ...
3
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1answer
1k views

ArcGIS 10.0/10.1 - arcpy - automate projection tool with different datum or projection

I am getting stuck with a task that is slightly different from the posts I found so far on this same website. Assumption: all layers have a defined coordinate system Problem: I would like to ...
3
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1answer
628 views

getting the specified geographic transformation, or at least the GCS, of a data frame

First, the TLDR digest: I'm getting a bogus value from dataFrame.geographicTransformations on some machines; how do I get the correct value as shown in the properties dialog? and/or Given a spatial ...
3
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2answers
346 views

Is NAD 83 the same as EPSG:4326?

I'm getting mixed messages about these projections. For example -Is this projection below, NAD 83, 4326? GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983", ...
3
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1answer
204 views

2 Shapefile vectors will not plot properly in same space

There are slight differences in 2 shapefiles projection information. I have activated on-the-fly, but they do not plot in the same space. I tried to save as new shapefiles with the same CRS, but ...
3
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2answers
935 views

Display two layers with OpenLayers at once

How can i display two layers with diferent projections at once? For example i have layer with EPSG:70076 and OSM layer.
3
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2answers
260 views

How do you change the prime meridian of a map?

I am working with the Natural Earth world map as a SHP file, but when I try to change the prime meridian (PRIMEM) of the coordinate system ...
3
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2answers
3k views

Why does QGIS scalebar show a wrong scale?

I'm using QGIS 1.7.1 and have added a scalebar. The scalebar usually displays in degrees, unless I switch the map's projection to meters, in which case the units are display in cm. This is not ...
3
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1answer
307 views

Ogr2ogr projection problem- features are shifted 12 miles to the north?

I have discovered a problem related to the output of an ogr2ogr command line call. My resulting polygon features are 12 miles (.18 degrees) due north of where they should be, but the longitude is ...
3
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3answers
4k views

How do I include proj4js in openlayers?

in my Openlayers app, since the base map projection is not epsg900913 or 4326, I need to include proj4js in order to use geolocation feature. but i got such a error notice: GET ...
3
votes
1answer
467 views

How to solve Projection Problem at client side

I want to discuss a scenario here to all. I have developed a Web mapping application in OpenLayers and GeoServer. The customer give us shapefiles with native projection SWREFF99_1330 (EPSG:3008). ...
3
votes
1answer
31 views

Why are Google Mercator and UTM rotated towards each other?

Being a self-taught GIS user, I struggled a while before getting the grips on map projections. But now this: because I like to use OpenStreetMap as a background layer for orientation, I have saved my ...
3
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1answer
113 views

Which projection is being used in this figure?

I would like to use the projection being used in this figure. Does anyone know which one it is? Esp helpful if it is available in ArcGIS. From plant stress page thanks!
3
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1answer
102 views

Convert planar distance to ellipsoid (real) distance

I have the following linestring which approximately marks an airport runway: LINESTRING(-381578.819887 6574044.360475, -378513.534443 6574799.475787) # EPSG 3857 LINESTRING(-3.427781 50.732117, ...
3
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1answer
23 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 ...
3
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2answers
242 views

Ortho Projection produces artifacts

I`m trying to create a sphere-like view using qgis and the "world from space"-projection http://spatialreference.org/ref/sr-org/6980/ (essentialy an ortho-projection). ArcGIS wraps the shapes ...
3
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1answer
90 views

Rhombus shaped pixels when viewing an image referenced in WGS84

Following the Question What is the projection of WGS84 in GIS software?, in the comments section of the answer http://gis.stackexchange.com/a/73578/5256, Jake very well explains that Because the ...
3
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1answer
297 views

How to render area that crosses 180°?

The problem is that the Chukotka Peninsula is located in the Western Hemisphere. So it is on the left side of Natural Earth Datasets. It needs to be moved to the right. I tried to use following ...
3
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3answers
585 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(...); ...