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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236 views

Which equal-area projection to use for UK?

I have a bunch of UK polygons that are saved in my PostGIS database as WGS84 projection. I would like to calculate the area of these polygons using st_area. According to this answer I can save these ...
1
vote
1answer
37 views

Coordinates freeze when I give a projection

I have recently begun to use arcmap and needed some guidance on a problem that I am facing. I have a district shape file with 200 districts with geographic coordinate system: GCS_WGS_1984. I need to ...
3
votes
1answer
32 views

Equatorial Scale

I have seen Equatorial Scale written along with the RF on the World Map in many Atlases, for eg., "Equatorial Scale 1:95 000 000". What does this Equatorial Scale mean and what is the significance of ...
3
votes
1answer
441 views

Openlayers 3 WMS Projection

I am working with both EPSG:4326 and EPSG:4230 in OpenLayers 3 and I am using my WMS service which only supports EPSG:4326 maps. What I need to do is show a map in EPSG:4326 and transform it to ...
4
votes
2answers
261 views

Why is the Google Maps circle shape not matching to the distance calculated with PostgreSQL?

I am running a PostgreSQL 9.1 Database with PostGIS 1.5 extension. Several coordinates are stored in there with type GEOMETRY (SRID 4326). I'm building a web-application with Google Maps Javascript ...
1
vote
1answer
38 views

Parameters of Normal vs. Transversal cylindrical projections

I need to parameterize a cylinder that cuts the ellipsoid. One time in normal case   (eg. like Mercator) and one time in transversal case (eg. like Transversal mercator). So, in normal case the cut ...
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2answers
36 views

Unknown Coordinate System Cadastral?

I have point data from a proprietary source that came in a coordinate system I do not recognize. Here is an example: Lat: 35205357 Long: -11.15933 It looks like a combination of UTMs and ...
1
vote
1answer
91 views

Is there a way to change the QGIS default CRS?

I'm working in a UTM projection and bringing in dxf layers from a different program. The dxf files are all in the correct UTM coordinates already, but when I bring them in I need to change the CRS to ...
1
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1answer
87 views

QGIS 2.4.0 CRS reprojection creates empty files and goes generally nuts

I consider myself an intermediate GIS user but keep running in a problem with the newest QGIS version I cannot fix and wonder if it may be a bug or if I am just too stupid. The problem mostly centers ...
0
votes
1answer
73 views

Creating a spatial reference in arcpy from projection name

I am using ArcGIS 10.2.2, Python 2.7. I want to create a spatial reference from the name of a projection, e.g. NAD_1983_BC_Environment_Albers, using the arcpy tool ...
1
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1answer
28 views

why am I getting a horizontal solid strip when projecting large image?

I am using Mapnik to create tiles on a tile server. I'm depicting sea level rise in North America using SRTM data, and it works fine in most of the continent. However, when zoomed out in my browser ...
2
votes
2answers
97 views

Mapping Russia - Int'l dateline splitting polygon

I am having the issue where the International Dateline is splitting a polygon I am working with. I have a layer of the "Federal Districts" of Russia, and the eastern most federal district is being ...
1
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1answer
105 views

Definition of the WGS 84

Hi i'm having some trouble getting the following things straight with , does this make sense? EPSG:4326 WGS84 Coordinate system: WGS84 Datum/Ellipsoid: WGS84 Projection: longlat
0
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1answer
31 views

Why Geowebcache is locking all system?

My story is like this about geowebcache. I am useing geoserver 2.5.x and GeoWebCache version 1.5.2, build 1.5.x. OS is ubuntu. I can not found geowebcache.xml file in server. But there is a file ...
1
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0answers
51 views

How i can have the same xMin,yMin for vector files in Qgis 2.4

i have a .shp file(polygon) in EPSG:2100 - GGRS87 / Greek Grid and an other .shp(points) in the same system(EPSG:2100 - GGRS87 ) but different xMin,yMin. The first has xMin,yMin 583309.00,4152885.94 ...
0
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2answers
56 views

How to link a shapefile with points to a shapefile with lines?

I have a shapefile with points (nodes) and a shapefile with lines (pipeline) which I have extracted from a water distribution network. I have been able to transform the points into the right ...
3
votes
2answers
344 views

Influence of the scale factor on the projection

I'm currently reading documentation about map projections to understand the source code of the Proj4 project. The scale factor is named in a variety of sources I read. This sources explained its ...
2
votes
1answer
80 views

J2000 to WGS84 in QGIS?

How to transform Earth-Centered Inertial J2000 CRS to WGS84 CRS in QGIS? I searched J2000 in spatialreference.org, however nothing found. I don't know the proj4 string of J2000. Any advice would be ...
1
vote
1answer
99 views

How do I convert a TIF to EPSG:3857

I'm trying to convert this TIF to EPSG:3857, but when I run: gdalwarp -of GTiff -s_srs epsg:4326 -t_srs epsg:3857 -co "tfw=yes" original.tif converted.tif I just get a black TIF do you know what I ...
2
votes
2answers
106 views

Is there an algorithm for transforming from CGCS2000 to WGS84?

Is there an algorithm that supports transforming from CGCS2000 coordinate to WGS84 coordinate? CGCS2000 is China Geodetic Coordinate System 2000. Any advice would be thankful!
0
votes
0answers
31 views

Projection of COSMO-EU?

I have data points of COSMO-EU data stored in WGS84 coordinates. Now I try to transform them into coordinate system where the points becomming arranged to a regular grid. Does anybody knows the Proj4- ...
1
vote
0answers
167 views

How to prevent cross-world lines in ggplot world map?

I'm having issues displaying 'great circles' paths and polygons in ggmap, an extension of ggplot2. Please enter the following code to replicate my issues: ...
0
votes
3answers
69 views

Empty shapefile after project tool in a for loop

I am running a for loop to process a years worth of data. The entire script runs fine for the first run through, but when it runs again (when date is 1/2/2013), I get the following error: 'NoneType ...
1
vote
1answer
65 views

Why does ArcGIS Online project my files right where they should be but, ArcGIS for desktop does not

When loading shapefiles into Arc Map 10.2.2 I get the message saying "unknown spatial reference", then my files are not projected where they should be and are usually too small to see regardless how ...
2
votes
1answer
40 views

Reprojecting from Wagner VII using QGIS

I have a shapefile in Wagner VII projection (well, the proj4 string really only is: "+proj=wag7 +datum=WGS84 +units=m"). I'd like to reproject it to WGS84 (EPSG:4326) using QGIS 2.6. However, when I ...
2
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0answers
48 views

Reprojecting PostgreSQL/PostGIS data as it streams in?

I have a postgres/postgis database. I would like to reproject those data coming to me in 4326 to 32736. For those tables with lat long info in wgs84 (4326) I have set the geom to 4326. Then I have ...
0
votes
1answer
41 views

Converting datum?

I need to measure the distance (with the ruler) of points from two different layers. However, one layer is NAD83 and the other is NAD27. I also have a standard ESRI basemap downloaded. The issue I ...
2
votes
1answer
34 views

Raster origin is incorrect, does not properly overlay with vector in same CRS

Two layers, both allegedly WGS84, one vector layer of the Midwestern US, one raster layer with coverage of the entire US. The vector layer renders correctly (coordinates are correct), but the raster ...
2
votes
3answers
68 views

Change projection didn't change position in a vector shape in qgis

I got a shape of points and when i save it with another datum and open it again, it stays in the same position. I was hoping for a slight change in position when save from epsg:5361 to epsg:32719.
2
votes
1answer
80 views

Partial loss of projection data converting to MapInfo File with OGR

I'm trying to convert some data from ESRI Shapefile to MapInfo TAB format using ogr2ogr. The data is projected using the British National Grid (EPSG:27700). The output file is valid, and the geometry ...
0
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0answers
65 views

GeoTiff using GDAL

How can I project a tiff using the position of the four corners where the picture have to be placed ? The tiff file has no georeference or projection information I have got a grid with values of ...
2
votes
1answer
113 views

How to transform this PostGIS type of projection to EPSG:900913 in OpenLayers?

I have transferred this kind of projection from this type(which I don't what type it is): 010100000054E077E6F8F33640FD87F4DBD7AD4340 to EPSG:900913. I have the points which are in the above format ...
2
votes
1answer
53 views

Python Geospatial Development Error

I'm working through some examples in the Python Geospatial Development book by Erik Westra. On page 439, about setting up a tile map server, he gives the following code for calculating a bounding ...
1
vote
2answers
145 views

Mercator vs. Web Mercator for Large Scale Topographic Maps

I have 8 terabytes of imagery that is in either lon/lat or UTM projection that I will be using for the basis of large scale topographic maps. I have been studying the differences between Mercator and ...
0
votes
1answer
60 views

Convert height Geoid EGM96 to ellipsoidal?

I'd like to convert the height data which is in EGM96 to Orthometric projection. Perhaps there are tools, like ArgGIS (I cannot find if ArcGIS can do this), or any formula that may help me.
2
votes
0answers
46 views

QGIS CRS correct, but layers appear warped

I am trying to overlay a raster Landsat 8 scene and vector scene boundary. Both are using WGS 84 + UTM48N. However, the vector (orange line) appears offset when overlaid on the raster. I have checked ...
0
votes
0answers
51 views

reprojecting (unprojecting) in MrSID decode (SDK)

I am using the C++ SDK (version MrSID_DSDK-9.1.0.4045-win32-vc9). I'm trying to read in arbitrary .sid files and extract rectangular sections of them that can be displayed on top of a "web mercator" ...
1
vote
1answer
11 views

Why my map just grayscale mode after use MRT?

i just follow the step to change .hdf file to geotiff file from this site http://duncanjg.wordpress.com/2012/12/11/loading-modis-ndvi-time-series-into-postgis-raster/#comment-1214 and i use data from ...
0
votes
2answers
179 views

How to store lat/long in PostGIS database? [duplicate]

I have a bunch of points in a text file that are represented using lat long (116.3158516 39.9748016). I import them into my GIS enabled database and create trajectories using st_makeline() as ...
1
vote
0answers
36 views

Can I get Geoserver to return a WMS in gnomonic projection?

I need to be able to pass in the center lat and long. I have tried using the AUTO Namespace for SRS (which works) but this only supports a few projections, the closest being orthographic. I have ...
2
votes
1answer
154 views

Definitive list of Proj4 supported coordinate systems

I need to determine the minimum set of coordinate systems supported by all tiers of my project's stack. I have a list of EPSG codes supported by Oracle and GeoServer but I'm having trouble finding a ...
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0answers
58 views

Appropriate reference system for small-scale mapping of the Middle East

I want to create a thematic map of the Middle East that displays certain historic places and regions on a small-scale map (between 1:6.000.0000 and 1:12.000.000). The map has to center the boundary ...
0
votes
1answer
257 views

OpenLayers 3 drag and drop interaction with custom projection problem

I am trying to add layers by using drag and drop interaction. Here is jsfiddle.http://jsfiddle.net/anuket/umdwzn10/ It almost works, I mean new layer is added, but for Geometry it gives "NaN". Geojson ...
2
votes
3answers
136 views

matching coordinate systems by transforming and projecting

matching coordinate systems of all my data (transforming, projecting) My data uses the GCS_Bessel_1841 coordinate system. Would there be any inaccuracies if i would transform it to DHDN 3-Degree ...
1
vote
1answer
39 views

Mapnik tiles have latitude distortion, projection issue?

I'm trying to work out a kink in setting up mapnik-node. My geos are in postgis, and I allllmost have them rendering properly, but my GIS experience is lacking so I can't seem to determine why this ...
2
votes
0answers
78 views

Mine Grid to UTM

I have been given spatial data (lidar) that was collected in mine grid feet in ASCII format. I am using arc to process but need to define a projection does anyone know how to do this or any other ...
2
votes
2answers
47 views

Formula for charting a course around the globe, given a location and degree heading?

I'm looking for a formula that takes a long/lat coordinate and a degree heading, (e.g. "I'm standing in San Francisco and I'm facing 45º from north"), and which can draw a line across a map projecting ...
2
votes
2answers
76 views

Overlaying misaligned DGN file in ArcGIS for Desktop?

I received a DGN file, I believe created in Bentley 8, and there is a bit of a misalignment problem. The dgn, when overlain on a Bing Maps aerial or NAIP image, shows up about 20 m or so off. I'm set ...
3
votes
0answers
184 views

Formula for maximum coverage of a geostationary satellite based on earth station elevation

I am trying to create a javascript function to represent the maximum coverage of a geo satellite for different antenna elevations (0 degrees, 5 and 10 degrees) with 3 leaflet polylines. The result is ...
4
votes
3answers
145 views

Geometric Operations in GIS Systems

I have worked with 2D geometry for CAD - My questions are general and relate to understanding operations on geometric entities (lines). Should geometric operations such as line-line intersection be ...