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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28 views

PTV_Mercator correctly recalculated to WGS84 EPGS:4326 but not correct on map

I have recalculated PTV_Mercator (PTV Spherical Mercator EPSG:505456) coordinates to WGS84 EPGS:4326 coordinates in Excel. And when checking them on Google Maps they show up correct. But after ...
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2answers
88 views

What's the accuracy of Web Mercator EPSG:3857?

Are there any references on the accuracy or (min/max/avg) error of Web Mercator when it comes to e.g. distance calculations? (For the sake of completeness, I haven't found any reference to the ...
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2answers
77 views

Why do my XY cordinates not make sense / show up in ArcGIS 9.3?

In the Add XY Data menu I selected to add a table containing UTME and UTMN coordinates. I selected a WGS84 projection b/c that's what the GPS device that meade the readings was set to use. However, my ...
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31 views

Issue on project CRS loading a georeferenced image

I have a georeferenced image in EPSG 26714. When I load it in Qgis 2.14 the project CRS is set to 4326. I asked for the layer properties and the CRS registered is 26714. When I open the same file in ...
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1answer
38 views

Projection issue with WMTS in QGIS?

I'm trying to connect to this WMTS in QGIS, but I'm having issues that I think are projection related. I use the Add WMS/WMTS dialog and enter this url: ...
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22 views

Given WGS84 bounding box, is there service that returns most accurate projection to use?

I'd like to find a service to convert lat/lon in WGS84 to an arbitrary coordinate system in metric that will be the most accurate for my bounding box. Does something like this exist? For instance, ...
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21 views

Multi Projections w/ openlayers 3

I am stuck and I need your help! My app needs to change projection and/or layer on click. I have a layerchooser class which controls the clicks (works well with alert("hellool3")) My main class is ...
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1answer
64 views

Distance measure of ST_ClusterWithin

I use SRID 4326(WGS 84). So what is the measure of distance in ST_ClusterWithin . m, km, degree ? I ask it because in documentation it only says: geometry[] ST_ClusterWithin(geometry set g, float8 ...
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1answer
45 views

How to use latitude/longitude with projection in R [duplicate]

I am using the SABS dataset: http://nces.ed.gov/surveys/sdds/sabs/ In particular, let's say I am using the "SABS_1314_High" layer. (This provides the school attendance boundaries for many US school ...
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13 views

Problem in adding geojson to WMSTile layer

I have problem with adding my geojson file to WmsTile (I see this layer). Here is my code with sample of geojson :
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51 views

How to deal with different projections in PostGIS spatial analysis?

I am doing something wrong, but try as I may, I can never seem to grasp all aspects of how to project layers in GIS. I am working with two files: 1) The USGS maintains a list of locations with ...
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1answer
30 views

My point shape file having missing spatial reference information

I am using ArcGIS 10.2.2. I got a shape file with points representing spot elevations in my study area. This file has been provided by a third party institution. The coordinate system is missing ...
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1answer
91 views

OL3 How to reproject vector layer on fly (ol 3.14)

I have a map in OL 3.14 with a WMTS in a specific epsg. I add a WMS layer in an other projection and it's ok, OL reproject right. But with a vector Layer (geoJson, in the same projection as WMS), ...
2
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1answer
37 views

Calculating Geometry in ArcGIS without a Projected Coordinate System

For my project, I want to calculate the geometry of individual polygons in my layer to find area and perimeter, however it is greyed out when I try to use this tool. Beforehand, I set the data frame ...
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1answer
25 views

How does ArcGIS project-on-the-fly in an Export Data task, to a different datum and custom projection?

I need all my data in an equal area projection to for an analysis that will calculate area at the North American Scale. The projection I want is custom, it has the following settings. I will be using ...
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21 views

Unknown coordinate system produced in 1980 by Japanese company in North Philippines

I am having the same difficulty with one of the report produced in 1980 by Japanese company. The grids format also N 38,578, E 41,400. The project is 390 kilometers north of Manila. I would like to ...
3
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1answer
50 views

Rotating ~90° using Two-Point Equidistant projection with Proj4

I'm trying to rotate a tif raster in R using Proj4's Two-Point Equidistant projection - I think the only way to rotate spatial geometries to custom angles. But I'm finding the operation gets very ...
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53 views

Reprojecting a raster file in R

Help! I have a number of rasters from different sources with different projections. I want to reproject the rasters into a common projection (Eckert IV), somehow line the grids up, and then overlay ...
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19 views

Raster and digitized shapefile misplaced in same projection

I have georeferenced .tiff rasters with cadastral borders and corresponding digitized borders in shapefile based on that raster. All that was done in some Mapsoft software. When I insert both in QGIS ...
2
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1answer
66 views

Getting village map into correct place on OpenStreetMap raster background?

Can anyone tell me the steps to display my village map (as a tif/tfw pair of files) over an OSM raster layer (from the OpenLayers plugin) in QGIS? Because every time I try my village ends up in the ...
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0answers
36 views

Problem with adding GeoJSON to OpenLayers 3

I transformed (.geojson file)from EPSG 2180 to 4326 using ogr2ogr -f "GML" -lco GEOMETRY=AS_XY -t_srs EPSG:4326 test.geojson file.geojson I would like to add to map, but I received this error : ...
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30 views

Where can I download a world shapefile with 180-degree central meridian?

Does anyone know where I could download a world shapefile that has a projection with a central meridian of 180 degrees longitude? I have found the following question that provides instructions for ...
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1answer
48 views

Problem with projection in OpenLayers3

I would like to add polygon geojson in the EPSG:2178 projection. The polygon should be displayed in central Europe but I see my geojson in Asia. Where have I made a mistake? Where can I find ...
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0answers
20 views

Layers do not overlap [duplicate]

I am new to ArcGIS. I have some layers. Three of them perfectly overlap and the fourth does not. I have tried with the Projection tool and I have tried so many things and nothing. When I check the ...
7
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1answer
235 views

Understanding difference between Coordinate System and Projection?

Can somebody please explain what is the difference between the Coordinate system (WGS 84 for example) and a Projection (Universal Transverse Mercator for example)? What is the difference between a ...
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44 views

Formula for Nicolosi Globular Projection

What is the formula for the Nicolosi Globular projection? In other words, what is the function that maps the coordinate (φ, λ) on the sphere to the coordinate (x, y) on the plane? You can assume ...
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29 views

Converting u and v from WGS84 to NZTM2000 - Do I need to do vector conversion?

I have u and v wind component values in latitude and longitude in WGS84. I want to convert this to NZTM2000. I've converted the lat/lon in ArcView - (and will try in R) - but do I need to also do some ...
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1answer
48 views

Changing coordinate system says that geotransformation is invalid?

I am planning on using the MODIS burned area products which were produced by Maryland University. These come as either polygons or rasters. In the user guide it says A shapefile version of the ...
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2answers
557 views

Which projection is this data in?

I received a shape file for my project from an agency and was told that they always use UTM. However, the values have too many digits for being projected in UTM. min max x 32507319 ...
2
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1answer
17 views

WFS Filter performed before or after reprojection?

I'm trying to perform a WFS filter with a polygon in EPSG:3031, (the native projection is EPSG:4326 I think). And I'm aware that WFS/GeoServer supports reprojection on the fly. But will the features ...
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0answers
50 views

Determining printed map projection?

A friend of mine is working on a small project to map receding North Pole summer sea ice minimums by decadal averages on a wall-paper map. Unfortunately, it seems as though the map projection for ...
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4answers
152 views

Get a coordinate system from raster file

I am writing a code to loop through all the files in a folder and reproject them, using a raster as the spatial reference. I have a suspicion that there is a different way to get the coordinate system ...
4
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0answers
55 views

How to choose the EPSG projection?

Up until now for reprojection of my WGS84 vector (.shp) and raster files (.tif), I have been using EPSG projections based on vector/raster central point's UTM zone. But what happens if the ...
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0answers
61 views

Geographic vs. projected raster cell size area

I am wondering the best way of knowing how to define the area of each raster cell in global data. Specifically, I downloaded all ~400 tiles of MODIS land cover data, mosaiced them into one, and now am ...
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2answers
81 views

Coordinates not displaying in UTM

Mac OS 10.9.5; QGIS 2.8.4-Wien; offending data here I want to calculate the centroid of a polygon in meters. However, I cannot get QGIS to display in UTM and I cannot transform/project the data to ...
2
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0answers
24 views

OpenLayers measurment path in 31700 projection

I have this code who works great for distance measurment on 900913 projection with 4326 display projection (bing maps + layer WMS): measureDistanceControl = new OpenLayers.Control.Measure( ...
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1answer
76 views

Getting inaccurate results converting from New York State projection to NAD83 with Python's pyproj

I've been trying to do a standard coordinate translation between New York State Long Island (ESRI:102718) and latitude/longitude (EPSG:4269)...but I keep getting the wrong lat/lng results. I don't ...
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39 views

Correcting for offset

I have a shape file with RTK measurements as a line feature, which more or less corresponds with visible features in a raster layer (shaped as lines). These measurements however are not accurate ...
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1answer
29 views

How to read info from the CRS? [duplicate]

I'm struggling to understand how the geo projections work in practice. The info a the CRS is as follows: {'ellps': 'WGS84', 'no_defs': True, 'proj': 'longlat'} Does it mean that the coordinates are ...
4
votes
1answer
159 views

Map projection classification - Tissot's indicatrices are perfect circles, but the projection is not conformal

Recently, led by the perfectly circular shape of the Tissot's indicatrices all over the projection plane, I have concluded that a particular projection is conformal. However, after calculating angular ...
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23 views

How to work with a shapefile that has no projection information? [duplicate]

In a shapefile I'm working with there is no information on the projection used. That is, no .prj file. Is there a hack/alternative way of determining what coordinate system the data is in?
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22 views

Geodesic replacement of coordinates [duplicate]

With a updatecursor I can move vertex to a new location and modify polygons. For a simpele example I tried to move the world, see image. The black lines are the 'edges' of world (180,90 -180,-90 ...
3
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1answer
54 views

Way to Shrink Alaska and Hawaii for “Stereotypical View”

Is there anyway to shrink Alaska and Hawaii to create a map that looks like the stereotypical map with AK in the corner, etc.? I thought about trying to isolate AK and HI in their own layers and then ...
0
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1answer
25 views

Reproject non-earth to ITM/ICS

I'm trying to convert MapInfo, non-earth projection, layers with data in ITM or ICS (Israel coordinates in meters). When I do so through Universal Translator with converting to SHP and back again, ...
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22 views

EPSG:4978 or others for Distance

Usually when I have been calculating distances I project to the system which has the tightest crop around my points e.g. for the UK #http://epsg.io/27700-5339 (accuracy: 1.0m) uk = '+proj=tmerc ...
4
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1answer
60 views

Why can't QGIS handle the Kavrayskiy7 projection although it is supported in proj4?

I'd like to make a world map using the Kravayskiy7, however QGIS seems to be unable to handle the projection, even though it is supported by proj4. 704900 (as is the EPSG for kav7) is not listed in ...
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0answers
19 views

In ArcMap, how much is a Zoom Out click [duplicate]

In ArcMap, when I zoom out (or in) a single mouse-click (not dragging a rectangle, just a click), what is the change to the ratio? If it is different between coordinate systems please explain it on ...
4
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1answer
53 views

Wrong shape display with North_Pole_Azimuthal_Equidistant projection

I need to create a map that displays the breeding and wintering ground of a bird species that has a circular arctic breeding distribution and winters in Africa. The map should lool pretty much like ...
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0answers
29 views

Trouble with Calculate Geometry in ArcMap 10.2? [duplicate]

I got a "Federal Lands" shapefile from nationalmap.gov. I clipped it down to the geography I am focusing on (a few counties in eastern California). I am trying to use the "calculate geometry" tool to ...
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1answer
35 views

Error distance for coordinate transformation (to WGS84)

I have a dataset with mostly EPSG:31255 and wanted to convert it to WGS84. I now had to realize that the results are up to 100m off when I plot them on a map or just enter the resulting lat lon in ...