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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2answers
1k views

How can I make a polyline wrap around the world?

I am using leaflet maps to create a representation of a round-the-world challenge. I would like to add a polyline which heads east from tokyo and then appears west of south america on the map - but ...
2
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1answer
1k views

Quantum GIS Reproject a projected coordinate system with rotation

I have two shapefiles:- one in WGS84 Z30S and one in a custom, system based, projection. I need to convert the custom projection into WGS84 Z30S. I have a set of parameters including a shift in X and ...
3
votes
1answer
840 views

What is wrong with this Proj4 transformation?

I'm implementing support for WMS maps in my company's software. Servers return a list of projections their maps are available in, but our software only displays data in WGS84 (lat/lon or UTM), and ...
2
votes
1answer
907 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: ...
4
votes
2answers
454 views

How to efficiently project datasets of varying coordinate systems into one coordinate system?

I am working on streamlining data processing at my organization. Currently we are using various large-scale Models that we will gradually bring into Python. The gist of our data processing is as ...
9
votes
2answers
698 views

What happens to feature class when importing to feature dataset?

I am creating a model that needs to ensure that all input datasets end up in the same coordinate system (among other things). I was originally going to batch project all of the datasets whether they ...
1
vote
1answer
618 views

Choosing best projection/SRID

I created a shape in OpenJump and exported it to shape(ESRI) file and then imported it to SQL2008 via shape2sql , the problem is that it shows bigger than what I want, In OpenJump it shows 1meter ...
1
vote
0answers
737 views

mixing lon/lat and mercator layers in a MapServer .map file

I have a basic question about my MapServer .map file, which has two layers, each with a different coordinate system, longlat vs. mercator. See my .map file below. If I leave it as shown below, with ...
28
votes
2answers
973 views

What projection appeared in the NYTimes this morning?

Perhaps not as GIS related as some, but definitely about maps. Can anyone identify the map projection that appeared in the New York Times this morning? It's not one I've seen before, and a quick ...
1
vote
0answers
86 views

List of methods of determining the projection of a shapefile when .prj is missing [duplicate]

Possible Duplicate: Best practices for identifying the unknown coordinate system of a Shapefile It would be helpful to mention what information is needed to perform each technique. What are ...
4
votes
2answers
1k views

TileCache and Openlayers Problem - Projections?

I have a very known problem, but I can't solve it. I have set the same maxExtents in the config as in the Openlayers init JS. I have done the same thing with the projection (EPSG:900913) and done all ...
9
votes
2answers
563 views

Is there a way to draw a straight line on a map which also represents a straight line on the earth surface?

I'm trying to understand more on projections. In this example, why must one calculate the curvature of the earth (great circle) if the map is already projected? Is there a way to draw a visibly ...
2
votes
1answer
185 views

OpenLayers.Control.DrawFeature Accuracy problem

When i draw a polygon using the OpenLayers.Control.DrawFeature then i export that polygon to KML using OpenLayers.Format.KML. Though, when I open it in google earth there is a big difference between ...
6
votes
1answer
916 views

projection/pyproj puzzle, and understanding SRS format

I have a shapefile that has a .prj file, with the following wkt contents: ...
6
votes
2answers
583 views

Is it possible to use the Goode Homolosine projection in QGIS?

Is it possible to use the Goode Homolosine projection in QGIS? Both QGIS and GRASS seem to have trouble with the interruptions, squashing the higher latitudes together. I tried +proj=goode ...
6
votes
1answer
8k views

Openlayers and Geoserver: OSM/Google Maps and WMS Overlay

I am experiencing projection problems with the following set up: GeoServer with ESPG:4326 based shapefiles (*.shp) OpenJump to edit my shapefiles Openlayers with EPSG:900913 base layers GeoServer ...
16
votes
5answers
11k views

Map projection in OpenLayers

I want to overlay some data whose projection is WGS-84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows: map = new OpenLayers.Map('map', { ...
10
votes
2answers
864 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 ?
2
votes
0answers
534 views

Arc by center point in PostGIS does not fit the circle

I'd like to store a GML ArcByCenterPoint in PostGIS. I can work out the start, middle and end points required by the CIRCULARSTRING type and all seems to be OK, except that when I visualise the arc it ...
5
votes
2answers
3k views

How to display KML image overlays in OpenLayers?

I am working on displaying Ground Overlays on OpenLayers by parsing KML manually. To do so, I was trying to add an image on top of Google Map by looking at GroundOverlay section from ...
5
votes
3answers
9k views

Using ArcMap, how may I convert a shapefile to use decimal degrees?

I have a shapefile that currently uses meters as the measure for its coordinate system, but the map framework I wish to use expects decimal degrees. I'd like to reproject my shapefile to use decimal ...
3
votes
2answers
2k views

How to set spatial reference to OSGB_1936_British_National_Grid in ArcGIS

I have two datasets in ArcGIS. One is from the Ordnance Survey (UK National Mapping Agency) and, when I view the properties of the dataset it says that the Spatial Reference is ...
4
votes
2answers
357 views

Reproject TM65 to OSGB in ArcGIS

I have a TIFF file in the TM65 (Transverse Mercator) projection, and want to convert it to the OSGB (British National Grid) projection. I'm trying to do this in ArcGIS using the Project Raster tool. ...
24
votes
3answers
565 views

Why are Data Projections relevant?

Sorry for my ignorance - especially after being in this area for a long time. Why is it useful to store data in unusual projections and datums? I understand the value of projections as output ...
2
votes
1answer
133 views

Projection Decision

I'm deciding on whether to use a geographic projection (lat/long) or a lambert conformal conic projection for a web servicing project that will use raster, vector, and point data, for queries, ...
6
votes
1answer
2k views

What's up with the GeoJSON spec and CRS as a IRM?

I'm writing a web API to our GIS data, currently revamping our geocoding service. I'm creating the option for folks to specify the output type as GeoJSON so I'm trying to follow the spec. Our data is ...
3
votes
2answers
4k 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 ...
6
votes
1answer
487 views

How does OpenLayers determine a layer's projection?

Could anyone explain the strategy OpenLayers take to determine the layer's projection? For example, if I didn't explicitly specify any projection for a marker layer, what projection would the layer ...
6
votes
1answer
219 views

What is the definition for a geographic coordinate system with east/west bounds of 0 to 360

I need the coordinate system reference or a projection definition that uses geographic (i.e. lat/lon) coordinates but instead of east/west bounds being defined as 180 to -180, I need them to be ...
2
votes
2answers
636 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 ...
3
votes
2answers
175 views

Can you search WMS services for a particular projection?

Is there an interface or website to search public WMS services for location/projection?
1
vote
0answers
411 views

Moving GPS Points with a VB script - Bearing works well but distance is wrong

I am using a script I found online created in 2003 by one of the commentators here. It is a great script and exactly what I have been looking for and I'm very glad to have found it. It simply takes ...
20
votes
2answers
2k views

What projections should I use to make my own Globe?

Searching for an answer to this question, I found instructions posted by Gulf of Maine Research Institute showing how to create a globe. Using manual methods ... What approach would I take to ...
46
votes
8answers
2k views

One dimensional map of the world?

Bit of a strange question but hope this is OK to ask here. Has anyone heard of a '1-dimensional' projection of the world map - that is mapping all the points on the globe to a single line? I was ...
1
vote
1answer
570 views

How to calculate oblique photo scale?

Is it possible to calculate oblique photo scale by given vertical photo scale ? I mean is there any kind formula relation between them or maybe is it possible to calculate rough approximation of ...
5
votes
4answers
3k views

Automate Projection of multiple shp files using ArcPy

I have been trying to create a Python script that will convert all shape files within a folder from GCS WGS 84 to Web Mercator. Below is the code I have so far but what I'm struggling with is how to ...
4
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 ...
6
votes
2answers
654 views

Using Python, Batch Project output won't drop into feature dataset?

When attempting to batch project in ArcGIS 9.3 or 10 (using either arcpy or arcgisscripting), I cannot get my geoprocessing results to drop into the feature dataset that I specify. The results ...
9
votes
5answers
4k views

Better Distance Measurements in Web Mercator Projection

I am working with an ESRI stack, storing my layers in a sql-spatial-enabled-SDE- geodatabase (Geometry type, Web Mercator-3857). I am building a web mapping application, so by default, the tiles are ...
3
votes
1answer
353 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 ...
1
vote
1answer
438 views

Issues with defining projection to that of the current root file

I am creating a shp file with the extent of all the raster file in a set of directories and it works fine when all the rasters are in the same projection but not when they switch around. So I want to ...
0
votes
1answer
1k views

QGIS and MapInfo Projections - EPSG 27700 (British National Grid)

I have some data in a PostGIS table with the projection EPSG 27700. If I export this data from QGIS (v1.8) to MapInfo TAB / MIF when I open the data in MapInfo it has a shift on it. Does anyone know ...
3
votes
2answers
476 views

Project twitter geo data into wgs 84 map

I'm currently working on displaying twitter geo data (currently just long/lat -> cartesian without any analysis). This is the world map (source: naturalearthdata): ...
5
votes
0answers
102 views

Is there a tool to retrieve the projection system used to create a shapefile when the prj file is missing? [duplicate]

Possible Duplicate: .shp with unknown coordinate system Are there any tools to help retrieving the projection system used to create a shapefile when there is no .prj file? Given that ...
2
votes
1answer
497 views

How to determine area of pixel in meters with GDAL and Python?

I have a raster loaded in Python using GDAL bindings. I'd like to be able to determine the area of a pixel in meters although I'm not confident that the projection is in meters. On this page I see a ...
7
votes
3answers
4k views

Why don't my Shapefiles and OSM data overlap in Quantum GIS?

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine Open Street Map data along with data provided by the City of Vancouver. But the City ...
1
vote
1answer
249 views

Lambert cylindrical projection support in PostGis

Does PostGis support Lambert cylindrical projection or is there a way to add support for it? I'm probably searching the wrong terms, but google isn't bringing up anything useful. Any help is ...
3
votes
1answer
571 views

How to generate a grid of horizontal equal-area rectangles in a Mercator projection?

I'm new to GIS so pardon my ignorance and bear with me. I'm generating a grid relative to a LonLat point. To make the cells all equal area, I'm creating it in 2163 projection. The problem is that when ...
4
votes
3answers
6k 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 ...
11
votes
4answers
2k views

How to reproject spatial data using free libraries?

How can I use free libraries to transform spatial data? For example, I want to change the projection of a Shapefile within the code of my C# web application. How do I do that?