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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Problem with projection of Slovenian Shapefile in QGIS

I hope someone can help me for this: I'm doing my masters thesis in Slovenia (in the field of wildlife management), for this I got a Shapefile of slovenian data by the University. As a main layer, I ...
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1answer
27 views

Proper projected coordinate system for Minnesota for measuring areas

I have seen in ArcGIS many different State Plane systems for Minnesota (location coordinates in WGS84: 44,07 lat/-94,61 long) within the Projected Coordinate system group: NAD 1983 (CORS 96) ...
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1answer
360 views

OpenLayers and custom Proj4 Projection

ok so I'm a newbee in using OpenLayers. I try to map some planetary data on my webMap server using OpenLayers. I defined a proj4 projection as follow: Proj4js.defs["MYDATUM"] = "+proj=longlat ...
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13 views

Pros and Cons of a latitude adjustment grid vs other methods of area calculations

When working with high resolution global raster data in WGS 1984 I often need to calculate areas. Now the traditional way for me to achieve this has been to reproject the data to an equal area ...
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7answers
918 views

Spatial reference for dummies?

Can anyone recommend a good reference or tutorial that explains the principles of spatial references, projections, and coordinate systems? We are a small team of programmers working with GIS ...
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1answer
39 views

How can I reproject a layer in a spatialite database

I'm writing an android mobile application and, for performance reasons, I want to reproject my layers to match the basemap's projection. Is there a command to do that?
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13 views

How can one use Google Maps API to mimic QGIS projection/CRS

I used QGIS to find the extents of a list of features. However, the resulting data auto-generates the CRS and changes it from WSG84 to a custom one. Is there a way to use the autogenerated CRS in ...
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82 views

TileStache : Unknown geometry type in geoJSON file

I'm currently trying to set up a TilSstache server on Ubuntu 12.04 to serve some GeoJSON tiles from a shapefile/JSON file (administratives boundaries) for a web mapping project using the Leaflet ...
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1answer
15 views

Difference between source SRS and target SRS in Raster Warp function

Hello I am trying to change a raster layer projections from WGS84 to a custom Lambert layer using 'Raster' --> 'Projections' --> 'Warp' function. I have been asked for source SRS and get SRS. what is ...
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20 views

List of possible options for a tif's spatial reference information [on hold]

Tifs are a very common file type for rasters/images because they are interoperable between many different software. In my experience, the way their spatial reference information is stored is not as ...
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6answers
7k views

Shapefile PRJ to PostGIS SRID lookup table?

I was wondering if there is such a thing as an shapefile PRJ to PostGIS SRID lookup table? Something that can translate the most standard shapefile PRJ definitions into the likely SRID. When using ...
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88 views

projection conversion from mercator to google maps format

Is this spTransform(Finland3, CRS("+proj=longlat +ellps=WGS84 +no_defs+ellps=WGS84 +towgs84=0,0,0 ")) the right way to project a shapefile with this projection coord. ref. : +proj=merc +lon_0=0 ...
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2answers
24 views

Custom projection problem with proj.4

I have some vector files that come without projection. So I have to define my own projection in QGIS. The information that comes with the data reads as following: Projection: Lambert Azimuthal Units: ...
2
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1answer
73 views

openlayers display projection

I'm displaying coordinates in epsg:900913 using ol.control.MousePosition() with OSM. I'd like to convert these on the fly in another epsg:2154. I call in the header : <script ...
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1answer
88 views

Lambert Conformal Conic Projection Inverse Transform after Fitting Ellipse to Noisy LLA Data

I'm using Python and Basemaps to convert some Lat Lon data to the LCC projection and back again. Since it is noisy data representing the footprint of a satellite, I am filtering it and fitting an ...
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16 views

Precision loss when transforming coordinates systems in GDAL (vector layers)

Anybody knows the order of magnitude of the error introduced when transforming coordinates using GDAL? More specifically, I would like to know if significant error is introduced when the ...
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1answer
24 views

ArcMap Area Calculations vs MultiNet FEATAREA Field Discrepancy

I'm finding a huge discrepancy between the values supplied in the FEATAREA field in my MultiNet data and the area calculation results from ArcMap v10.2.2. In this case, I'm looking at the area of ...
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1answer
48 views

Is the bilinear resampling technique appropriate for the projection of ASTER data?

I need to project some ASTER data from a geographic coordinate system to a projected one. I have read online that the cubic resampling technique is the most appropriate for this purpose. However, ...
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32 views

Transforming between epsg:3857 and Google Maps Tile coordinates

Hio, I used to use a simple python project (https://github.com/hrldcpr/mercator.py) to convert between wgs84 and google maps tile coordinates. This project doesn't have a license, and looks like it ...
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19 views

Guessing a map projection by its values [duplicate]

This is more a theoretical question and not an actual problem that I have. Is it possible to identify or classify projections by their numerical coordinates? Or alternatively rule out in some sort of ...
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0answers
17 views

Projecting Data with Transformations - Alignment Issue

Problem: I am having problems getting data to align properly with basemaps layers. The image below shows the difference between roads. The centerlines shapefile's coordinate system is ...
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1answer
190 views

Mercator bias plot in Leaflet

I was inspired by this wikipedia image from the mercator projections page to hack around with leaflet. The idea was to interactively have your cursor move a continent and that it would be corrected ...
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18 views

How to get ASTER level 1B data to overlay correctly on google earth/ bing maps/ arcmap imagery basemap

I have recently purchased Two granules of ASTER 1B data from ERSDAC. Upon importing this data into arcmap 10.2, the layers representing each band were specified as being projected in: ...
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1answer
94 views

Show map using esri leaflet, with 4326 spatial reference

I have this MapServer http://geoservices.big.go.id/arcgis/rest/services/RBI/Rupabumi/MapServer It turns out it uses 4326 spatial reference. I want to present it using leaflet, my code so far: ...
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1answer
30 views

How to import and project ASTER 1B data into Arcmap?

I recently purchased a granule of ASTER 1B data from ERSDAC, when I import any of the associated rasters into ArcGIS, the image is displayed as being only 1m across, when the actual area represented ...
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2answers
419 views

OpenLayers WMS - TypeError: this.resolutions is undefined

I'm trying to setup a map with WMS and WFS Layers by using Geoserver. However, when I'm combining WFS and WMS (with some Google basemaps) together in one map I got following error in Firebug: ...
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1answer
423 views

Determining Natural Origin for a GeoTIFF file (Lambert Conic)

I am trying to display an existing GeoTIFF file (from the FAA WAC set) in an application that requires the GeoTIFF NaturalOriginLongitude tag (FalconView 5.1.1). There are some older files in that set ...
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1answer
92 views

How to reproject from Clarke_1880_RGS_Lambert_Conformal_Conic to ETRS_1989_LAEA?

I am unable to reproject Marseille shapefiles from Clarke 1880 RGS_Lambert_Conformal_Conic to ETRS_1989_LAEA. I know that Clarke is a geographic coordinate system and it has no datum. I have tried ...
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1answer
49 views

Reprojecting MODIS Ice Sea Temperature products with gdalwarp

I have problems projecting MODIS Ice Sea Temperature (IST) products to EPSG:3031 (Antartic Polar Stereographic) using gdalwarp. The product I'm working with is MOD29E1D, documented here, p33: The ...
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1answer
24 views

Short list of .prj options in .pyt

I'm tasked with creating a .pyt to distribute across our office and field computers (state geological survey) for converting .gpx to features but constraining the choice of projections/datums to seven ...
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3answers
72 views

Problem with Geometry SRID in PostGIS

I ceated my table (borne) in PostGIS id_borne serial NOT NULL, num_borne character varying, shape_borne geometry I successfully changed the SRID of my table using select ...
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2answers
48 views

Choosing projection to use for Least-Cost Path analysis at continental scale?

I am trying to find least cost paths from the southern USA to the Great Lakes region (for example). My resistance layers are currently in an equal area projection but I'm wondering if I should convert ...
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27 views

Reprojecting a base map in ArcGIS

I am new to ArcGIS. I have the EDN license (Desktop and Server); have setup ArcGIS for Server in our offline environment; have published several base maps (with caches that ESRI provided me on a DVD) ...
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1answer
28 views

correct projection of GADM data

I'm trying to use a map of Austrias districts from the GADM project. The Shapefile can be found here: AUT_adm.zip (All other formats provided by the project appear exectly equal.) The coordinate ...
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2answers
397 views

GDAL/proj4 equirectangular projection coordinate system units assumed by OGRSpatialReference and GDALDataset::GetGeoTransform()?

How do I configure my OGRSpatialReference object to specify an equirectangular projection system http://en.wikipedia.org/wiki/Equirectangular_projection where the affine geo-transform matrix (provided ...
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2answers
53 views

GDAL for Python: extracting subdomains from NetCDF file?

I need to make a script that processes a NetCDF file that contains 3 days of hourly forecast data from the norwegian meteorological office. The NetCDF file contains various data I need ...
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1answer
209 views

Projection to use with satellite image from Google Maps / Earth

I'm very new to anything concerning GIS so please forgive me if this question has been asked before, but I assure you, I've been trying to find an answer for quite some time now. Of course it is ...
9
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3answers
231 views

A global, grid-like projection for creating heatmaps

I'm putting together an application where I need to create a vector grid which will be used to store and display a heatmap. It has the following requirements: Can cover the entire planet. The vast ...
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1answer
117 views

Trying to set NAD 1983 EPSG 102631 in QGIS

I was able to find the right coordinate system online NAD 1983 Alaska But now I don't know what to do. I can't find the coordinate system on QGIS. When I choose the one I think is correct it warps ...
36
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3answers
17k views

EPSG 3857 or 4326 for GoogleMaps, OpenStreetMap and Leaflet

The discussion at What is the difference between WGS84 and EPSG4326? shows that 4326 is just the EPSG identifier of WGS84.. Wikipedia entries for Google Maps and OpenStreetMap shows that they both ...
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0answers
53 views

How to overlay a flat image onto google maps with two points of reference?

The Android API allows for images to be superimposed onto a map. To do so, the developer specifies a set of lat/long coordinates for an "anchor point" within the image, the width (or height) of the ...
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1answer
51 views

Reprojected Shapefile does not align with Openlayers Plugin

I am based in NSW, Australia. I have a shapefile that when I underlay with the openlayer plugin (google satellite), the shapefile is skewed despite all my efforts to correct it. I changed the ...
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2answers
36 views

QGIS doesn't create the correct projections when creating new shp files

I received shapefiles exported from ArcGIS with EPSG:2227 as the CRS, which should be: +proj=lcc +lat_1=38.43333333333333 +lat_2=37.06666666666667 +lat_0=36.5 +lon_0=-120.5 +x_0=2000000.0001016 ...
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2answers
26 views

What's the purpose of the reference latitude in Lambert Conformal Conic?

Going through flight school I got acquainted with the Lambert Conformal Conic projection, as it's the common projection for VFR sectional charts, and I think I have pretty good grasp of it, ...
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91 views

How do ESRI and QGIS calculate scale values of geographic projections?

Does anyone know how (from which location) scale values are calculated in ESRI products and QGIS for geographic projections? The only thing I've noticed is that QGIS is changing scales when you pan ...
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2answers
83 views

How do I convert Geo-Coordinates to Pixel-Coordinates on a Map?

I have an image file that is a Robinson Projection Map of the world. I have a list of geo-coordinates. I would like to find the pixel-coordinates on the map that correspond to my the geo-coordinates I ...
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30 views

Striping Artifact in Aster DEM Mosaic

I'm working with SRTM and ASTER data for a university project. My goal is to delineate watersheds and evaluation of these with ArcGis 10 and ArcHydro. But a striping error occurs with the flow ...
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1answer
60 views

Change projections depending on the zoom level

Is it possible in ArcGis (from a technology/performance/… point of view) to switch projections depending on the zoom level? For example, Is it possible when zooming at some extent to the poles, my ...
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1answer
42 views

Crop and reproject shapefile based on GeoTIFF sample

I have GeoTIFF with these attributes: Size is 495, 309 Coordinate System is: PROJCS["unnamed", GEOGCS["unnamed ellipse", DATUM["unknown", SPHEROID["unnamed",6370000,0]], ...
3
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1answer
210 views

1944 Cyprus Grid coordinate data projection problem in MapInfo

I have coordinate data from the 1944 British Army General Staff, Geographical Section (GSGS) Cyprus map which was cast on the Cassini projection, but was referenced to the Clarke 1880 ellipsoid where ...