Tagged Questions

A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane

learn more… | top users | synonyms (1)

1
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1answer
39 views

Set default projection of geometry objects in arcpy

I have a script that creates a polyline geometry from scratch using some math to generate coordinate pairs. At the same time, there is a user-defined polygon shapefile that is used to "erase" the ...
7
votes
0answers
176 views

Geotransformation for polar stereographic?

I'm currently working to import CANGRID climate data (provided as Surfer Grid ascii, ".grd" files) into ArcGIS. The grid is 95 rows by 125 columns in size.Metadata provides lat/lon of origin (lower ...
1
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0answers
40 views

Clustering the WGS84 point features (projection transformation aspects)

My question is quite trivial and was discussed many times before (like here) but in our case it has the confounding extra requirements... The list of sparsely distributed 2d point features is stored ...
3
votes
1answer
59 views

How to plot a full hemispheric orthographic projection in R

I want to make a plot like that using R: All I want is the country borders as seen from outer space, no fancy colors needed. It seems I need to use the spTransform function, but it gives me a "non ...
1
vote
1answer
61 views

Difference between ETRS89 / ETRS-TM32 and ETRS89 / UTM zone 32N

In QGIS I can choose among other things between "ETRS89 / ETRS-TM32" and "ETRS89 / UTM zone 32N". In my test project both projections displayed the layers at the very same place. So, where is the ...
3
votes
1answer
73 views

Trouble calculating areas in QGIS using field calculator

I am testing various projections to calculate areas using ICES statistical shapefiles and the QGIS field calculator. I am using ICES areas downloadable from the following link: ...
2
votes
1answer
54 views

QGIS crashing when using 'save as' to save a new projection

Every time I try to save a layer with a new projection using 'save as' my QGIS crashes. The new files are there but they seem false. Please see two screenshots attached, one before and one after I ...
5
votes
2answers
93 views

Is there a standard for the specification of .prj files?

We use shape files for data exchange. I've looked at the .prj files: different programs produce different prj files. Is there a standard how the parameters must be specified in a prj file? AFAIK the ...
1
vote
1answer
43 views

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 ...
2
votes
1answer
64 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) ...
0
votes
0answers
23 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 ...
0
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0answers
22 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 ...
1
vote
1answer
23 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 ...
1
vote
1answer
49 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?
2
votes
2answers
37 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: ...
0
votes
0answers
31 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 ...
1
vote
1answer
31 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 ...
2
votes
1answer
145 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 ...
3
votes
1answer
59 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, ...
0
votes
0answers
171 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 ...
0
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0answers
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 ...
1
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0answers
21 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 ...
0
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0answers
22 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: ...
1
vote
1answer
45 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 ...
1
vote
1answer
26 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 ...
1
vote
1answer
51 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 ...
3
votes
2answers
153 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) ...
0
votes
2answers
122 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 ...
2
votes
1answer
82 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 ...
1
vote
0answers
158 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 ...
1
vote
2answers
36 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, ...
3
votes
2answers
41 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 ...
9
votes
0answers
154 views

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

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 ...
1
vote
1answer
78 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 ...
0
votes
0answers
58 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 ...
3
votes
1answer
68 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 ...
1
vote
1answer
72 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]], ...
0
votes
1answer
32 views

Issue with gdal getprojection and setprojection returning different information

I am using Landsat imagery from the USGS. Those who use them may know that the projection attribute is wrong (everything is in the Northern hemisphere). I have a script to process tar.gz files and ...
1
vote
1answer
42 views

Equal Area Projection for Central Ethiopia (37N)

Can anybody please tell me what is the best equal area projection for central highlands of Ethiopia. I am assuming Albers Equal Area Projection. Any suggestions?
4
votes
2answers
68 views

Projected coordinate system for South America

Does anybody have any suggestions for a projected coordinate system for the Northern part of South America? I have a data set that reaches from Venezuela to Southern Peru and I'd like to do some ...
-2
votes
1answer
80 views

Identifying projection for shapefile with unknown coordinate system, no z values and no measures? [duplicate]

I am attempting to create a GIS Project with multiple Brazilian cities. I have been collecting, and am interested in, shapefiles that delineate the neighborhood boundaries of said cities. One city's ...
1
vote
1answer
86 views

Tiled raster image to be placed in an OSM/ Leaflet.js map

I have a mapoverlay in a custom projection which I need to add as a layer to an Openstreet map within a website. Since I was not able to change the projection earlier, I decided to manipulate the ...
0
votes
0answers
58 views

How to generate map tiles with TileStache and a custom projection

I would like to generate my own map tiles using TileStache and a custom projection. I have been struggling with this for quite some time and am hoping I can get some advice to get the tiles to ...
9
votes
3answers
251 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 ...
2
votes
0answers
44 views

How do you clip a gnomonic or stereographic azimuthal projection?

I have polygons comprised of lat/lon coordinates and I want to project them onto a plane that's appropriate for polygon operations (such as checking for intersections). In some cases, the polygons ...
2
votes
2answers
51 views

Help projecting Austria data with QGIS

I'm trying to reproject this dataset from Austria Statistik Geodata. Data comes in "MGI_Austria_Lambert", and I'm trying to reproject to WGS84 What I'm doing is Saving layer as... and selecting ...
2
votes
1answer
180 views

Changing map projection and adding graphic features in projected coordinate system using ArcGIS API for JavaScript?

I'm having some problems with the ArcGIS API for JavaScript. I have a web service that traces an electric network and sends back JSON with point and polyline (path) geometry. I've created a function ...
2
votes
0answers
177 views

ArcGIS WGS84 Web Mercator Vs. WGS84 UTM zone 15N: Very different distance dimensions

I am working in ArgGIS 10.1 with a field (raster layer in tif format) in which I have placed two points (.shp layer). I have two versions of both layers, resulting four layers: one tif+shp set in CRS ...
2
votes
1answer
137 views

Pyproj: converting WGS84 to Robinson

I have a WGS84 coordinate pair (37.7749295, -122.4194155). I have an image that is a Robinson Map Projection of the world. I'm trying to write a python script to locate my WGS84 coordinate on my ...
3
votes
2answers
90 views

Google layers not matching

I'm working in a project with whole Europe data. I'm working with WGS84 (4326), and sometimes I overlay my polygons with Google maps layer (in QGIS) to see some details. When I do this, I have to ...