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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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
16 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 ...
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29 views

Why is the project tool in ArcGIS (ArcMap) for desktop throwing the “invalid geographic transformation” error?

I'm trying to reproject a point shapefile from ITRF92 to WGS84 UTM ZONE 14 NORTH. On the geographic transformation input field, I copied and pasted the following geographic transformations from the ...
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1answer
18 views

Plotting netCDF4 data with the right projection

I guess this will sound simple to you but I just cannot get the right plot within R. I have a netcdf4 file and would like to visualize it within R just like I would do in QGIS and ArcGIS. sample data ...
3
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2answers
31 views

Projection issues with Leaflet - polygon appears off

Using Leafletjs to upload coords from a json file as a polygon. The original coordinates are Vicgrid94(3111). I used QGIS to change the projection to LatLng (4326). When I load the points onto my ...
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2answers
31 views

How to calculate area in sq m - troubleshooting projection issues in a global dataset in QGIS

I am using QGIS version 2.12.3. I have 3 polygon shapefiles: A, B and the intersect of A and B, which we can call C. All I want is to add a field to the attributes table of each shapefile giving ...
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1answer
25 views

Encode an azimuthal equidistant projection in NetCDF conversion

I'm trying to do Azimuthal Equidistant in CF-compliant NetCDF, but I didn't get the correct projection. If you compare the first two information (gdalinfo) you see there is no AUTHORITY and also ...
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1answer
20 views

Difference in EPSG:28992 (RD/Amersfoort) definitions

I need to do some projections between WGS84 (EPSG:4326) and the Dutch RD system (EPSG:28992) in JavaScript. I use Proj4js for this. When adding the definition from spatialreference.org I noticed a ...
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1answer
26 views

Arcobjects Assign projection transformation to layer file in VB.net

I want to be able to transform a layer from WGS1984 to OSGB1936. I created a tool that extracts layers from several folders on our company network folders, using check boxes that user clicks. One of ...
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17 views

Projecting the Coordinate Systems of layers but one layer doesn't show up with the rest of the layers

I have data from two folders I am working with. Each folder contains shapefiles. The shapefiles in each folder need to have their coordinate systems projected to NAD_1983_UTM_18N. There are 6 ...
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1answer
32 views

Vincenty or (Project + Euclidean) for accurate distances

I posted a similar question on stackoverflow, however was directed here for more help. If my main goal was to calculate distances such that my error was minimised to the nearest metre assuming that ...
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1answer
48 views

Convert to lat-lon coordinates GDAL

I have a netCDF file and would like to convert it to LAT-LON coordinates. 1) I do not know the projection in the file but from the website of the data provider, the data is on a polar-stereographic ...
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22 views

Project NetCDF file using GDAL or QGis

Can I project a NetCDF file with the help of GDAL or QGis? The file info is: gdalinfo c:\tomcat-6.0.36\webapps\ncWMS\layers\RAIN_MM_1hour_ac.nc Driver: netCDF/Network Common Data Format Files: ...
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1answer
14 views

calculating ratio of areas on a sphere

I have 2 shapefiles and after identifying their intersections I'd like to know the ratio of intersecting areas, e.g. a given shape S in file1 intersects with shapes (x1,...,xn) in file2 with ...
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1answer
918 views

Can Mars be mapped in ArcGIS

Can I use ArcGIS to map planets in particular Mars? Where would I start in terms of basemapping and projection?
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22 views

How to calculate false easting/northing for Lambert Conformal Conic projection

I'm defining a new GRASS location using the Lambert Conformal Conic projection. My understanding is that the values for the standard parallels and central meridian are dependent on my area of ...
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1answer
26 views

Correct Projection for calculating centroids of a group of points?

I have a long list of points covering all of North America for which I would like to calculate the centroid (by grouping points based on the "Name" column). My approach is to take the WGS84 ...
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1answer
29 views

What projection to use in POSTGIS for LAT/LONG and 'contains' queries

I would like to store latitude / longitude information in a POSTGIS database. I will need to query that data with simple contains query (for display on a map, so the bounding will be simple box) and ...
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1answer
56 views

projection (WGS84, UTM) issue

I have a question about projections. I have a hillshade raster with UTM 31N projection (I reprojected this from WGS 84). I also have a satellite image that I need to georeference. For georeferencing I ...
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2answers
30 views

Projection for using ArcGIS as CAD [closed]

I want to use ArcGIS to map my apartment. How can I create a projection file (with which parameters)?
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12 views

Intersect Iso_rectangle_2 with Polygon_2 where Polygon_2 uses Projection_traits_xy_3

I have a set of [Point_3][2] that constitute a Polygon_2 using the Projection_traits_xy_3 typedef CGAL::Exact_predicates_inexact_constructions_kernel K; typedef CGAL::Projection_traits_xy_3<K> ...
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1answer
17 views

Plot image on map based on corner coordinates

I have a color image and I know geographic coordinates of its 4 corners. Now I'd like to place this image on basemap in GMT using any projection. Any idea how to do that?
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1answer
68 views

convert lat/lng to pixel and vice versa

This had been asked previously on Stack Overflow. I've tried different methods/formulas but results are not correct. 40.764296,-73.97302 should result into 930,3590 pixel on map image. I've Manhattan ...
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1answer
49 views

Shapefile projections not matching up in QGIS?

To start off with, I'm very new to QGIS. I'm attempting to place a shapefile with locations for 3 substations on a map of Peniche, Portugal. The locations for the substations are given in latitude and ...
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2answers
46 views

How to re-project a shapefile to be compatible with another shapefile or raster?

I have a polygon shapefile and a raster. The shapefile and raster have different coordinate systems. Coordinate System for the shapefile: NAD_1983_UTM_Zone_19N WKID: 26919 Authority: EPSG ...
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43 views

The drawing of Thiessen/Voronoi polygon boundaries - are the bisecting lines truly perpendicular?

I am concerned with how QGIS (version 2.8.1) and ArcGIS (version 10.0) draw "perpendicular bisecting lines" when Thiessen/Voronoi polygons are created. When using either program to create these ...
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1answer
35 views

Which map projection should I use for a country land cover map?

I am currently completing a piece of GIS work and I am a bit stuck, even after doing some reading. What would the appropriate map projection and co-ordinate system be for a land cover map for a ...
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1answer
64 views

Why do my layers that are in the same projection not align?

According to the data frame properties window, all of the layers are in the same projection. However, the Snowplow Routes don't align properly with the lakes and bella_vista_roads layer. Are there any ...
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14 views

connecting ecw to its projection and grid data in an xml file

I'm new to mapping please go easy on me:) I have a bunch of ecw files with 2 xml file one is a file ending with *.ecw.xml and one with *.ecw.aux.xml I am trying to load the ecw files into ...
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20 views

Converting Grid to Geographic?

My project specifications are as below: utilise geodetic and shift parameters between WGS84 and specified datum (ED50), local projection (UTM 31N, CM 3 East) and transformation (EPSG1613) for all ...
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35 views

OpenLayers 3 - in-house tiled ArcGIS basemap not visible

I am new to openLayers. I am trying to display an in-house cached basemap from an ArcGIS REST service. I can see the basemap if I use "ol.source.TileArcGISRest" for the source property, but the ...
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2answers
47 views

Does Oracle Spatial calculate geodetic distance?

I've got to migrate a PostGIS database to Oracle Spatial, and am stuck on a problem: In a view, I have a column that amounts to ST_Distance(geography(geom_1), geography(geom_2)), effectively ...
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1answer
39 views

Reprojecting and retiling a large set of tiles

I am trying to understand the process to re-project and re-tile a set of raster (GeoTiff) but can't wrap my head around how to use the different GDAL tools to achieve my goal. More concretely, I ...
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1answer
27 views

How to describe a MODIS Tile's distortion

When looking at the MODIS grid [1] and compare it to how the sinusoidal projection is distorted, I wonder how to both practically and formally describe the distortion factor for each MODIS grid tile. ...
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9 views

Taudem - Failed to execute while processing projected raster

At the moment I'm trying out some tools in ArcGIS 10.3 with the TauDEM toolbox. I want to process a raster with tools like Pit Removal, Flow direction etc. (Creating a watershed based on DEM). It ...
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1answer
27 views

Defining the correct AEA proj4string for FEWSnet Rainfall Data (Southern Africa) in R [closed]

I have some general questions about how to go about solving this problem: I am trying to incorporate FEWSnet's monthly Rainfall Estimate data from 2014-2015 for Southern Africa into an analysis where ...
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2answers
36 views

What is the SRID of LCC projection?

I have a raster file with LCC projection and a point dataset with SRID 4326. I want to extract raster value to point. When I use the query SELECT ST_Value(rast, geom) val FROM testraster5, ...
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mapnik.Gdal(file=my_latlon_raster_file_path) returns a datasource with an empty all_features() list

When I get my mapnik layer datasource like that for a raster file: layer = mapnik.Layer(my_raster_layer_name) layer.srs = my_srs layer.datasource = mapnik.Gdal(file=full_path_to_my_raster_file) and ...
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1answer
57 views

Choosing projection to make Arizona look “normal”?

I am having issues projecting my AZ state boundary from looking like this: to looking like this: I found that I could use the U.S. National Atlas Equal Area to get the shape I want, but when I ...
3
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40 views

Transforming lat and long to Mercator x and y

I've been trying to plot a set of lat and long coordinates to a Mercator map using the following set of equations; x = long - long0 y = ln(tan(pi/4 + lat/2)) These equations are from a page on ...
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3answers
61 views

Area units for output polygon in WGS 84 UTM Zone 32N using QGIS

I am calculating the area of my polygon and I have used WGS 84 UTM zone 32N to calculate the area (using geometry on the field calculator) of my polygon, and I obtained 745461 (without units). How ...
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2answers
55 views

Inferring lat/lon based on known location coordinates

I have a point dataset with a set of coordinates that is in an unknown projection. For some of these points I know the unprojected latitude and longitude. Based on these known data points, would it be ...
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2answers
68 views

Inaccurate Buffer Distances

When buffering a point, the result is inaccurate to the basemap. I specify a 200 foot buffer around a point however the resulting buffer has a distance from the point of about 260 feet. Both the ...
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1answer
30 views

Alternative to Web Mercator projection that does not look too small on phone?

My issue with Web Mercator as a projection to use online is that I think it gives people an unrealistic perception of space. Greenland looking massive is a good example. One benefit of Web Mercator, ...
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1answer
46 views

Shift in the data between CartoDB and stamen layer, Google Maps API

I have a geojson loaded into CartoDB database. And I have a CSV file too. Names field would be common in both the GeoJSON and CSV file. I had written a logic if the place name in CSV matches the place ...
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1answer
20 views

Polygon Surface Area Calculator in different map projection(s)

I'm simply looking for an online tool or a utility to calculate the surface area of the same polygon (i.e shapefile) in different projection (projected and geographic projection system) systems. It ...
3
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1answer
49 views

What is the real distance between positions?

I'm trying to figure out what gives me the most accurate distance between positions: Measuring distance directly (using Geod.inv)? Measuring distance in 2D (after transforming to a known projected ...
3
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0answers
41 views

Choosing projection for routes that fall within two UTM zones? [duplicate]

I'm creating charts for routes that fall within two UTM zones; 30S and 31S. The offshore routes are in the Alboran / Balearic Sea - connecting Spain to Algeria. What projection should I use?
3
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2answers
73 views

What is a suitable map projection for the entire state of Idaho?

I am working with some sample GIS data for Idaho. The data is in geographic coordinates but I want it in projected coordinates. I am unsure how to address the issue of projection as Idaho crosses ...
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1answer
23 views

Using map units to define radius of point feature in styles in QGIS: not getting it right

I have a point feature in a map which is in EPSG32723 (WGS84 - UTM zone 23s) and I need to style it as follows: A center point in red and a circle below it which has a particular size in meters. I ...