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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10
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2answers
1k 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
650 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 ...
6
votes
3answers
12k 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 ...
4
votes
2answers
457 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. ...
27
votes
3answers
826 views

Why are Data Projections relevant?

Why is it useful to store data in unusual projections and datums? I understand the value of projections as output constructs, because of distortion, etc: that much is justifiable. However, I don't ...
2
votes
1answer
135 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, ...
7
votes
1answer
4k 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
5k 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
551 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
239 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
732 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
181 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
432 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 ...
53
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
689 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 ...
5
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
724 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
5k 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
408 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
488 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 ...
4
votes
2answers
573 views

Project twitter geo data into WGS84 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
103 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
560 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 ...
8
votes
3answers
5k views

Shapefiles and OpenStreetMap data do not overlap in QGIS?

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine OpenStreetMap data along with data provided by the City of Vancouver. But the City ...
1
vote
1answer
282 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
726 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
7k 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 ...
13
votes
4answers
3k 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?
3
votes
1answer
650 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). ...
1
vote
1answer
156 views

Get relative north aligned point 2163 (US Equal Area)

What I'm trying to do is create a grid where the y axis is north aligned. I have a origin Lat/Lon point which is the bottom left corner of the grid and each cell should be 100 by 100 meters. So I ...
1
vote
2answers
820 views

Can I project 3D DXF vertical cross section into a “plan view projection plane” for display in ArcMap?

Below is the lenghty explanation but simply put my question is: How can I project a 3D DXF file (vertical cross section) into a "plan view projection" for use in ArcMap? I am using Target (by ...
7
votes
1answer
3k views

Computing UTM Zone from lat/long point?

I am trying to convert a latlong point to UTM. To define UTM projection, I need to calculate zone for the point. I am trying to figure out the best way to do this. One way to do this would be ...
8
votes
4answers
12k views

How to reproject base layers in OpenLayers?

The issue is: I have vector/topo/image tiled maps for some places in north america which were published as ArcGIS Server REST service. These maps (A) are based in EPSG26912 projection. Now I wanna ...
0
votes
2answers
1k views

How would I convert this point to WKID 4326?

This is a point in Brewster, MA, USA. How would it be converted to WKID 4326? 324299.3348436486, 832511.5939650714
4
votes
2answers
2k views

How to “calculate” distance-to-ground of all 18 OSM zoom levels?

Assuming I'm building a 3D solution with the "world" being mapped to global geo-data supplied by OSM / Cloudmade... think http://www.webglearth.com but with completely different goals and use-cases. ...
3
votes
2answers
259 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 ...
2
votes
1answer
789 views

Rendering 3D timezones KML on a 2D map

I'm trying to render a KML layer (with timezones) in Google Maps API v3. The KML layer works fine in 3D (in Google Earth), but when I render it in 2D, the timezone lines that meet at the North Pole ...
48
votes
4answers
8k views

Why has Web Mercator (auxiliary sphere) become the web map standard?

I understand what the difference is between the Web Mercator projection and Web Mercator Auxiliary Sphere (WMAS). I also understand that both Google and Esri have adopted this projection as their ...
0
votes
2answers
286 views

Shp's will NOT line up (coordsys) - shps made using GPSeismic sotftware (client made shp's)

OK, I asked this previously but solved it on my own last time. Same project, but differant shp files. I recieved from a client shp files that were made in GPSeismic 2011. Upon recieving the shp ...
2
votes
1answer
97 views

Coordinates are not aligning

The two shapefiles (shp) are not aligning like they should (note the img). The layer and the two shp files have all the same coordinates - NAD_1983_StatePlane_North_Dakota_North_FIPS_3301_Feet The ...
1
vote
2answers
652 views

Project WGS84 to Google using MapGuide and WKT

I'm having trouble projecting a simple WGS84 formatted layer over google maps. I can't find a good WKT "API" that not only shows parameters, but explains what each parameter is. The coordinate system ...
6
votes
1answer
900 views

SRID error in mapserver

I've created a network topology using QGIS, saved it as a shp, imported it into PostGIS using shp2pgsql and I'm now trying to output some of the geometry using mapserver. Unfortunately mapserver is ...
3
votes
0answers
1k views

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 ...
0
votes
1answer
577 views

How to point out a city from a map image of world with longitude and latitude?

have a map image 800px wide. How can I figure out a city. like New York has 40.75 latitude and -73.98 longitude. I have to pin a mark over this point. Before I have done with x_axis and y_axis which ...
1
vote
2answers
611 views

Setting projection of tif file in QGIS? [closed]

I get this error when trying to define a projection for a tif file in QGIS: ERROR 1: Too many points (3249 out of 3249) failed to transform, unable to compute output bounds. How do I work ...
2
votes
1answer
543 views

How to resize layer using .prj (WKT) projection? (Geographic Coordinate System)

Briefly: How to parametrize .prj WKT file so that I can perform 7 point tranformation (wiki). I know how false_easting and false_northing params work, but how can I adjust scale? I do not mean ...