A reference framework consisting of a set of points, lines, and/or surfaces, and a set of rules, used to define the positions of points in space in either two or three dimensions.

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6
votes
2answers
1k views

Why do my Shapefiles not align correctly?

First: I'll summarize what I understand so far so please confirm or correct me. When On-the-Fly is selected a layer is re-projected from that of the layer's CRS to that of the project CRS, IF ...
5
votes
1answer
348 views

Unknown Old Coordinate System of the Phillipines

I am reading a report made in 1979 and the coordinates show N 46,400 and E 47, 600. This is in the Philippines. Would anybody know what the coordinate system was used in this numbers? Thanks.
11
votes
2answers
4k views

Is there any online tool for converting coordinates between different EPSG?

Every time I want to do conversion, I need to get into the console to run proj.4. Is there any online tools for converting coordinates between different EPSG?
3
votes
1answer
149 views

What are the highest and lowest precision Coordinate Reference Systems for US East Coast?

And does it matter what system your data layer begins with if you choose the right system for your project? Do some applications use more precise projection systems than others?
0
votes
1answer
306 views

Geostationary satellite projection to be introduced in GDAL

I'm working on raster files and their spatial reference system is: PROJCS["Geostationary_Satellite", GEOGCS["GCS_Unknown datum based upon the custom ellipsoid", DATUM["D_Not specified ...
0
votes
1answer
283 views

CRS Conversion problem

My question is quite simple, this is probably why I couldn't find a conclusive answer anywhere. I have two datasets representing the same area in Romania, but in different CRS, A is local, B is WGS ...
5
votes
2answers
12k views

Coordinate system and projection for georeferencing Google Maps image in ArcGIS Desktop?

I have saved Google Maps image (not Google Earth) of area at latlon(17.692437,83.218689) by some method in jpeg format. It is an exact snapshot of the Google Maps. Now I need to geo-reference it to ...
1
vote
1answer
216 views

Why are the areas covered by 2 Universal Polar Stereographic (UPS) coordinate different?

According to http://en.wikipedia.org/wiki/Universal_Polar_Stereographic_coordinate_system. the area covering Arctic is less than Antarctic. Any reasons for it? It is due to the shape of the lands?
2
votes
1answer
533 views

Is it possible to convert data from WGS84 to Bessel1841?

When we convert data from bessel1841 to WGS84, parameter setting must be used because it is impossible automatic convert on QGIS. Reference: Converting shp file from bessel1841 to WGS84 Is it ...
0
votes
1answer
58 views

Is it possible to download GPX another coordinate system except WGS(GCS) with GPS Tool on QGIS1.8.0?

I got GPS data with using bessel1841 as coordinate system. When I download GPX data on GPS tool, it is automatically treated as WGS84. Can I use another coordinate system when I download GPX on GPS ...
13
votes
1answer
10k views

Which is correct projection in ArcGIS Server for EPSG:3857/900913?

I want to publish a mapservice in ArcGIS server, which will be overlayed on Google Maps or Bing Maps. For this, the Map Service needs to be in EPSG:3857/900913. The Google Maps projection is supposed ...
0
votes
1answer
76 views

What kind of unit of measurement for scale does SQL Server 2012 Spatial use?

What kind of unit of measurement for scale does SQL Server 2012 Spatial use?
2
votes
1answer
138 views

How to get a list of all projections that are currently available in QGIS via the PyQGIS-API

i'm building a QGIS-Plugin and i want the user to choose a CRS out of a combobox in which the coordinates he would enter into some textfields are represented, so these can be converted into another ...
0
votes
1answer
320 views

Why are layers not overlapping to each other inspite of having same CRS? [closed]

I am new to QGIS and working with QGIS 1.7.3 version, I have my all layers in WGS 84 CRS but even though they are not overlapping to each other, What should I do ?
4
votes
2answers
4k views

How to calculate distance between two points with esri.geometry?

The function http://help.arcgis.com/en/webapi/javascript/arcgis/jsapi/#namespace_geometry/esri.geometry.getLength should calculate distances between points. When I am trying to calculate distance ...
2
votes
2answers
676 views

Misaligning shapefiles in QGIS, OpenLayers and ArcGIS Desktop?

I'm working with a set of shapefiles and have some problems with the "align" of them in QGIS when I load Openlayers to reference some points. OLs has an straight horizontal baseline but the shapefiles ...
3
votes
1answer
1k 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 ...
0
votes
0answers
977 views

How to represent clustering of geographical points on map in STATA?

I've plotted a map on STATA using user-written program spmap and have also obtained the grid for my space using spgrid program. Now I want to see where most of my data points are clustered on map. Is ...
2
votes
1answer
319 views

Problems with NAD27 projection in QGIS

I have some data that is in NAD27, but I am having a hard time displaying it in QGIS. I think that the problem is with the CRS. I cannot seem to find the correct NAD27 option. The closest one seems ...
4
votes
1answer
164 views

Problem with custom projection definition in Qgis

I want to define a custom crs valid for Mexico. The context is that older cartography in Mexico is based on the NAD27 datum. I wanted to test the following proj4 string +proj=longlat +ellps=clrk66 ...
2
votes
3answers
2k views

How to handle layers with different spatial references in ArcGIS Runtime SDK WPF?

I am currently writing the "Zoom to Layer" function for my application. However, the spatial references between my imported layer and my base map are different. Is there a way around this? Can I ...
3
votes
2answers
2k views

Convert GPS coordinate to ArcGIS x,y point?

I'm trying to plot some AGSSimpleMarkerSymbol's in a AGSGraphicsLayer. The issue I'm running into is that the data I'm starting with are GPS coordinates (lat/lon). I'm using AGSPoint to plot the data, ...
1
vote
1answer
422 views

matching georeferenced jpg with GPS data in WGS84 [closed]

I have imported my georeferenced jpg which I believe (on the basis of metadata in xmml file) to be in the NZGD2000 TM coordinate system. metadata: Origin: 1.76759e+06,5.94938e+06 Pixel Size: ...
2
votes
1answer
190 views

Need to convert from ISpatialReference to SpatialReference

I am attempting to write a method in C# that will accept as input, an ESRI.ArcGIS.Geometry.ISpatialReference object and convert it to an ESRI.ArcGIS.Client.Geometry.SpatialReference object. I need ...
3
votes
1answer
5k views

What is the relationship between ITRF and WGS84?

Why are there people saying that "I am using WGS84(ITRF96)"? There are newer version of ITRF. Will WGS84 follow it? If so, what will be the influence to us?
5
votes
2answers
4k views

Location of Coordinate Systems folder in ArcGIS 10.1

To make it easier to find and select the 3 or 4 coordinate systems we use most often in ArcGIS 9.x and 10.0 we would copy them to the top of the Coordinate Systems folder, generally located in ...
2
votes
0answers
44 views

Spatial indexing of a point pattern in R [duplicate]

I have a point pattern and a tessellation (grid) in R. Is there a way to spatially index each of my points? In other words, my tessellation grid has n quadrats, I would like to know for each of my ...
2
votes
1answer
89 views

Transforming from WGS84 UTM30N to British National Grid (BNG)?

I am using ArcGIS 10 and trying to work in British National Grid. My shapefile is in WGS84 UTM30N. I passed the shapefile across to a colleague and we both transformed into BNG. When we compared ...
2
votes
0answers
230 views

What's the difference between CRS 4326, CRS 4978, and CRS 4979?

CRS 4326, 4978, and 4979 are all based on WGS84. 4326 is called "geographic 2D" 4978 is called "geocentric" 4979 is called "geographic 3D" What are the differences between these three? And why ...
4
votes
1answer
413 views

Can I say WGS84 is more accurate than NAD83 in terms of their reference ellipsoids?

Other than its application, can we say the reason of common adoption of WGS84 is due to its accuracy?
6
votes
1answer
643 views

Coordinate system in aerial imagery

I am calculating WGS84 coordinates of points in an aerial image, given the WGS84 coordinates of the center of the image and the ground distance width and height (calculated from altitude and lens ...
9
votes
1answer
1k views

How can I see the coordinate transformation parameters in QGIS?

How can I see (and edit if possible) the transformation method and parameters used by QGIS for "on-the-fly" transformation, and then for saving data in another CRS? Like in ArcGIS? Here is the ...
5
votes
1answer
261 views

How do I make the scalebar accurate when I am working with a google satellite image in QGIS?

I start a project in QGIS. I set the CRS to anything (in this case I use EPSG=26918 a NAD83 datum). I also enable on the fly projection. Then I import a vector. In this case a kml, which I believe is ...
3
votes
1answer
4k views

Converting geographic coordinate system in R

I have points in geographic coordinate system and I wanted to convert them to swiss grid (CH1903+). Sample data: id lon lat 2 7.173500 45.86880 3 7.172540 45.86887 4 7.171636 ...
5
votes
1answer
893 views

How to Display the World Map in Projected Coordinate Systems

I am trying to create a simple presentation map and I download the global level country boundaries shapefile from http://www.diva-gis.org/Data. The layer coordinate system is in Geographic Coordinate ...
5
votes
1answer
196 views

Where is the Spatial reference ID stored in SpatiaLite?

I have loaded a shapefile into a SpatiaLite Database using the spatialite-gui. In which table is the Spatial reference ID or EPSG code (of the stored data)stored in SpatiaLite?
2
votes
1answer
136 views

British National Grids projection does not add Ordnance Survey grids to shapefile?

I have created a shapefile in ArcCatalog by right-clicking the folder I want it in, then selecting new, then shapefile, then changing the type to "polygon", and using the British National Grids under ...
2
votes
1answer
579 views

QGIS 1.8.0 - Define shapefile as UTM 15 NAD83 Feet

I have a shapefile which the .prj file says it is ...
8
votes
2answers
2k views

Nearest point on a line ( Spherical / Mercator projection )

I have a line (Ax,Ay - Bx,By) over a mercator projection (google maps) and a random point (Cx,Cy) nearest to that line, i would to know the closest point (transparent blue on the image) over that line ...
5
votes
2answers
16k views

Convert X,Y State Plane coordinates to decimal degrees

I have 1000's of data point I need to convert from North Central Texas 4202 into Lat/Long decimal degrees. Can someone give me a conversion equation so I can quickly convert using excel? I have only ...
2
votes
1answer
1k views

Reprojection from WGS to Slovenian Gauss Kruger in QGIS

I have gpx file (track) in WGS84 (EPSG: 4326) coordinate system from Garmin GPSMAP 62 which is right projected in BaseCamp and MapSource. When I save track as *.GPX and import it to QGIS and use ...
2
votes
1answer
193 views

Difference between NAD83 Indiana SPW in QGIS and ArcGIS for Desktop?

It seems ESRI and QGIS don't have the same definition for my most commonly used projection, NAD83 StatePlane Indiana West (US ft). When I create data in an ESRI product the projection shows up in ...
1
vote
1answer
2k views

SRID 4326 and geometry conversion

From this line: SELECT ST_AsEWKT(geom) FROM buildings LIMIT 1; I get this result: "SRID=4326;MULTIPOLYGON(((404269.308014269 4543087.6184561,...)))" I'm wondering if the coordinations are ...
2
votes
1answer
142 views

What are the geometric principles and GIS techniques that I can use to generate a postcode coverage of my city at street scales?

Postal codes of Brazil and another countries are oriented to distribution logistics, and improvement of reliability in writing the postal addresses; but without much concern for the spatial ...
1
vote
1answer
222 views

Why does Find_SRID return zero?

using SELECT Find_SRID('public', 'myTable', 'myColumn'); I get zero as the result, what does it mean? Regards,
2
votes
2answers
861 views

What can go wrong in UTM to WGS1984 conversion (shifted data)

I try to convert .shp files to OSM data with shp2osm and ogr2osm but the output data is shifted. Semi-Cross-Posting Warning: I have already asked a questions on the OSM help site, but this questions ...
7
votes
2answers
213 views

Which SRS to use for global distance queries?

I have a database with a lot of points in WGS84. Now I am building an cache that performs NN and points in range queries using a KDtree. The point [sic] is that the search radius will be provided in ...
2
votes
1answer
350 views

Converting map to use space oblique mercator projection using ArcGIS for Desktop?

I have a map document in ArcMap which I want to convert to using Space oblique mercator projection, but I am not sure if ArcMap supports it. Any hints on how to achieve this?
0
votes
0answers
118 views

How do I determine programmatically what values to add to the proj4js constructor for a CRS or SRS such that I can iteratively render proper overlays

I think this is primarily a GIS based question as far as for example: var crs = L.CRS.proj4js('EPSG:2154', '+proj=lcc +lat_1=49 +lat_2=44 +lat_0=46.5 +lon_0=3 +x_0=700000 ...
2
votes
2answers
199 views

Coordinate system of a raster file to be introduced for transformation

I am working on raster data using GDAL. When I extract coordinate system information of the files I got this: PROJCS["Geostationary_Satellite", GEOGCS["GCS_Unknown datum based upon the custom ...