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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11
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1answer
500 views

Assign projection to a satellite image

Today I stumbled upon a picture taken from the ISS looking down Europe and it is really beautiful. So, I started thinking I could add more to the picture. Like world borders, cities, road network, ...
1
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1answer
696 views

how to make the translation between latitude/longitude and screen pixels

The earth is three dimension object while our screen is two-dimension. So when we use the gis software to display the geographic data, how do they handle the translation between latitude/longitude ...
3
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1answer
50 views

Does IDistanceOP.EucDistanceFull require a projected coordinate system?

I have designed an implementation of ArcObjects' IDistanceOP.EucDistanceFull. It takes its input as a feature class and converts it to a GeoDataset with which EucDistanceFull can work with. It works ...
2
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1answer
249 views

Do FeatureLayers reproject their features to adapt them to the map projection?

I'm working with the ArcGIS Flex API. For example, ArcGISDynamicMapLayers do reproject their data in order to make it in the same projection as the map. Do FeatureLayers have the same behaviour?
0
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0answers
21 views

De facto QGIS projection for EPSG4326 / 'unprojected' reference systems? [duplicate]

This is my understanding of projections/datums: To get a map of the earth on a plane you need to project the 3 dimensional earth by 'wrapping' a plane around it in the way that suits you (according ...
1
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2answers
495 views

define a datum and meridian in a CRS in QGIS

I have a shapefile defined by the source as: "The layer is in geographical (lat-long) coordinates (GCS_Clarke_1866; Datum: D_Clarke_1866; Prime Meridian: 0)." opening the shapefile in QGIS 1.8 the ...
0
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0answers
38 views

QGIS: Unable to project raster layers correctly on a Toshiba Tecra 64# Win7

I know how to project a raster, I can do it on other machines. On this particular machine the raster loads but are no where near the correct position as if the datum is on another planet.
4
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2answers
752 views

Why isn't valid geometry not valid in NetTopologySuite when close to poles?

I have a Polygon which crosses the south pole: Polygon in WKT: POLYGON((5.86826073458095 75.6638564054071,-16.5436836399021 63.2220742891438,-19.3664667294083 59.846221066959,-21.7009816876343 56....
1
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1answer
379 views

Incorrectly Projected PostGIS data in TileMill

When I bring PostGIS data in EPSG:900913 into TileMill, my layers end up on other continents. This is my workflow: (1) Save shapefiles in QGIS to EPSG:900913 (2) Import the shapefiles using PostGIS ...
1
vote
1answer
866 views

Wrong projection on WFS layer with OSM baselayer [duplicate]

I am trying to add a vector layer with a WFS protocol. var wfs = new OpenLayers.Layer.Vector("WFS", { strategies: [new OpenLayers.Strategy.BBOX({resFactor: 1})], ...
1
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0answers
70 views

how to get correct geo reference system for a VMap

I am new to GIS, trying to read the GeoRef System for VMap by using the following code: OGRSpatialReference *ref = layer->GetSpatialRef(); if( ref ) { QString georefSystem = ...
3
votes
1answer
227 views

Compute global DEM topographic indices and compromise projections

I would like to compute global topographic indices based on SRTM elevation data. These indices are computed along river/channel networks extracted from a DEM and are a functions of both local slope ...
0
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0answers
131 views

How to get Earth radius in pixels?

I need Earth radius in pixels for use in Mercator projection. Well let's say that our map's height is 1478 pixels and distance between 0 pixel and 1478 pixel is 2.52 degree. Radius is distance from ...
1
vote
1answer
2k views

openlayers multiple layers with different projection

My page contains two layers: 1. Open Street Map as a basic layer and WMS layer from mapserver as a overlay layer. My map show this two layers but in a wrong position. I spent a lot of time trying ...
10
votes
2answers
465 views

How do I perform a 3 parameter geotransformation and projection in Sql Server 2012?

I have a table with latitude longitude (NAD27) columns in it. I compute two other columns, X and Y, representing Web Mercator (WGS84) location. Currently I'm using a Arcmap to do this, by applying ...
3
votes
1answer
98 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 ...
0
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0answers
192 views

I want to change EPSG:4326 to EPSG:900913 using C# for a set of uploaded shapefiles

I have written some code (using help from these pages) that uploads a directory full of shapefiles to a geoserver using C#. The uploaded shapefiles are set to EPSG:4326 however I would like them to be ...
6
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1answer
215 views

Which training courses in Geodetics can you recommend?

Can anyone recommend any training courses in geodesy which would cover the following objectives: Case studies on coordinate issues Overview of geodetic datums, coordinate reference systems and ...
1
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0answers
388 views

Reprojecting raster data from a rotated pole grid

I have some raster data (ASCII grid files) that use a custom rotated-pole projection, that I'd like to reproject into something more useful, such as lon/lat WGS84. A description of the grid projection ...
1
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2answers
973 views

WFS reprojection problems

In geoserver i have a layer in EPSG:4326. In OpenLayers i add it on map as WFS: markerLayer = new OpenLayers.Layer.Vector('Markers',{ strategies: [new OpenLayers.Strategy.BBOX()], ...
0
votes
1answer
109 views

Imported GPS data does not overlap with map

I´m working on QGIS and I geocoded 2 addresses of a city in Germany and tried to input the text-file as a layer. It worked, but the 2 points must be in the map of the city and if I zoom to the layer-...
2
votes
1answer
116 views

Ok to measure and union a projected-on-the-fly shapefile in ArcMap?

I have a dataframe in arcMap 10.0.4 that is of Africa Albers Equal Area Conic PCS. I bring in a census shapefile of WGS 1984 CS and it is projected on the fly. I do 2 things: I use the calculate ...
2
votes
1answer
683 views

Transformation of user-defined projected coordinatesystems

I want to transform from one projected coordinate system (pcs) to another using ArcGIS 10. Unfortunatelly the starting system is not predefind by ESRI and thus I´m not sure the software is doing what ...
0
votes
2answers
138 views

Getting a “square” of lat/lon for database query [duplicate]

So I want to get the square formed by a single point of lat/lons, my plan was to take that point's latitude, divide by 360, and multiply by the circumference of earth. Giving us the distance from the ...
1
vote
1answer
119 views

Setting coordinate systems in gvSIG: workflow or transformation issues

I am learning how to use gvSIG 1.10 (Mac OS 10.6.8 Snow Leopard). My goal is to create a simple county map of Illinois using the base data shapefiles available from the Illinois Natural Resources ...
1
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0answers
186 views

How to join edge of International Date Line in world file?

I am currently using world file (http://www.ngdc.noaa.gov/mgg/shorelines/gshhs.html) for international boundary information. Now I have difficulty with map projection that the map ends with ...
1
vote
3answers
105 views

Trying to match delimited text layer to my shapefile

I'm pretty new to QGIS and having a bit of trouble getting a text layer to match my shapefile. I'm trying to plot Canadian cities on a shapefile I have of Canada provinces. The provinces shapefile is ...
1
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0answers
39 views

Determining the SRID of a dataset in PostGIS [duplicate]

Sometimes the dataset provides some information about its projection. For example, it can mention Horizontal_Datum_Name: North American Datum of 1983, Ellipsoid_Name: GRS1980, ...
2
votes
2answers
4k 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 ...
2
votes
2answers
545 views

What's the correct transformation for Lambert Conformal Conic for Wyoming?

I am a newb in QGIS. I have loaded QGIS 1.8 (Lisboa) and practicing with a number of maps for portions of the state of Wyoming. My maps are mostly in UTM 12N NAD 27 & NAD 83 some are in decimal ...
4
votes
1answer
437 views

What's the difference between Geographic coordinate system 4019 and 4121?

I have a DEM with cell size 100,100 with geographic coordinate system GRS_1980_Transverse_Mercator, Datum: D_GRS_1980. I created some extra shapefiles with projected coordinate system: Greek_grid, ...
2
votes
1answer
732 views

Correct coordinate systems, but trustworthy distance between points?

I have limited GIS experience with projections and I have some questions about trying to accurately display point data from two different sources in ArcGIS 10.1 in order to do a proximity analysis. ...
3
votes
0answers
64 views

Projection string for GOES-WEST

Full-res, full-disk GOES-WEST images are available from goes.gsfc.nasa.gov. Is it possible to rig up a projection string for these images? We know the center pixel is at (0N, 135W) and the satellite ...
11
votes
3answers
15k views

How can I get the proj4 string or EPSG code from a shapefile .prj file? [duplicate]

I have to work with a shapefile defined in an unusual projection, which my GIS software does not know about. How can I get the proj4 definition or the EPSG code for the projection?
1
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0answers
104 views

How to import multiple shapefiles each with different source projections to postgis

I have a couple thousand .zip files each with a .shp, .dbf, .shx, and .prj inside them that I want to load into postgis. The problem is, they have many different source projections (each defined in ...
1
vote
2answers
69 views

problem about reprojection

I am a new GIS user, I have some problem can not be solved by myself. I get a shape file generated from an Excel file. at first, my projection is WGS_1984_UTM_Zone_48N some data are inside my country ...
2
votes
1answer
557 views

Which BC Albers should I use and is there any difference?

I was about to calculate the area of some polygons and before I did I did some research. I found that the area of the polygon will be represented in the units of the projection used. So I did some ...
0
votes
1answer
284 views

constant deviation projecting lat lon to itm(israel tranverse mercator

i use two different ways to project lat lon data taken from google earth to ITM (Israel Transverse Mercator) and export the data to arcmap same ways i try to unproject ITM data and export the data to ...
1
vote
1answer
173 views

Projection WGS 84 is slightly displaced referring to a hillshade in QGIS

I have a hillshade and a vector layer. The vector layer is slightly displaced referring the hillshade. About lat=100m and long=175m The CRS of the project is EPSG:3397 - PD/83 / Gauss-Kruger zone 4. ...
4
votes
2answers
2k views

Cartesian world sized projection WKT/EPSG code?

I am after the EPSG code or Well Known Text (WKT) of a projection that puts the centre of the earth a 0,0,0 and each point is a cartesian XYZ distance from that. My existing data is in WGS84 lat/...
6
votes
1answer
132 views

Should I Reproject Data Which Has Been Captured Incorrectly?

I'm working on a project for a client which is migrating data from an Oracle database to an ESRI Geodatabase. When data for this project was initially captured over 15 years ago, the coordinate ...
0
votes
0answers
75 views

export WebMap in a different projection than the WebApi

I am quite new to the Flex WebApi world. I am using the Flex WebApi and have set up map templates to print maps out to my own template as a PDF. In my template I have the Map grid set. When I eport ...
3
votes
1answer
172 views

CRS Austrian Lambert/WGS84

I am totally new to Qgis (or GIS in total): My problem is to get two layers in same CRS to do an intersection and further analysis described in the blog of underdark (Groupstat tutorial). My is the ...
0
votes
1answer
2k views

Conversion from N,E to Lat/Long And Lat/Long to N,E will always be same? [closed]

I have an excel tool for the conversion of following lat/long: Lat: 23° 11’ 24.67503’’ S Long: 118° 46’ 6.15742’’ E , which gives me following N,E: Northing: 7,434,317.43 Easting: 680,991.69 But I ...
4
votes
0answers
248 views

Proj4 inconsistent longitude after projection

All coordinates expressed in this question are (longitude, latitude), the default for proj4. London is at (-0.1460838, 51.5170986), and San Francisco is at (-122.419302, 37.775549). According to the ...
1
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0answers
79 views

Projection for Tracking a Vehicle

I'm looking for the best coordinate system projection to use for cartesian calculations while a vehicle is running from its starting location to about 100 miles from that spot. The offline format ...
3
votes
1answer
317 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 ...
4
votes
1answer
345 views

Error in Min. Bounding Geometry results

I'm getting consistent, weird results from using Minimum Bounding Geometry to make circle polygons. I'm not sure if a datum issue, but I'm leaning more towards something wrong with Minimum Bounding ...
3
votes
3answers
415 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 ...
7
votes
5answers
10k views

OpenLayers: ALL image layers are out of place on google maps v3 and OSM base layers

Summary: I have 2 different image layers that looked fine with my old mapstraction/google maps based system. Using the same coordinates as bounds in openlayers results in a shift to the north by like ...