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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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
60 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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14 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
34 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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99 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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56 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
70 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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71 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
59 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
70 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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32 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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22 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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0answers
104 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
80 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
53 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
36 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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43 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
40 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
56 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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0answers
10 views

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
94 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 ...
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49 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
134 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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69 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
102 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
37 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
78 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
52 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 ...
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1answer
74 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 ...
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42 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?
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108 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
30 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 ...
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54 views

Wrong area using Albers Equal Area Projection in GRASS for Java, Indonesia

I am just getting to know GRASS 7.0 and I am struggling finding a good projection to work on a spatial analysis of Java, Indonesia. I am new to the forum, so if information's are missing for a better ...
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2answers
167 views

are these two proj4 utm projection strings equivalent?

I have a list of proj4 calls. Some of them have one format and some have another, I've been told they are equivalent. Is that so? If so, which one should I use? for example, for ETRS89 / UTM zone ...
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1answer
37 views

Projection of WMS in MapInfo

I am using the OSM open Roads WMS layer that comes included with MapInfo. I have noticed that when I load this layer the projection of the Map window changes to 'Popular Visualization CRS.' All the ...
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5 views

The effect of setting the reference system as “Unknown” when building stereo block

I couldn't figure out what is the effect of setting the reference system as “Unknown” when building stereo block in Erdas.
3
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1answer
21 views

GCS and PCS data misalignment in ArcMap when zoomed in

I have a shapefile in NAD83 UTM18 which I need to get into GCS NAD83. I tried both loading it into an empty GCS NAD83 feature class directly and the "project" tool. The results are the same - the ...
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52 views

Projection Issues - OpenLayers / MapServer / NAD83 State Plane FT

I am having projection issues with OpenLayers version 2.13 with MapServer and the Proj4 library. Pulling layers in NAD83 State Plane Feet projections on top of an OSM or MapQuest Base Map in Google ...
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1answer
39 views

Importing ESRI:102091 Monte Mario reference system

I am trying to import a dataset generated by my local council (Turin, Italy). The data appears on the map but it's slightly shifted and it doesn't match the Open Street map layer that CartoDB uses ...
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38 views

Converting coordinate obtained from google maps to be used with gdal_translate in java or cs2cs?

this is a follow on question from Geo-Referencing an image from google maps with gdal_translate I am trying to get cs2cs to work but I am getting the following error. My command is as follows: ...
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1answer
63 views

Geo-Referencing an image from google maps with gdal_translate

I am trying to geo-reference an image using gdal_translate in a command prompt. Currently I have the following gdal_translate.exe -of GTiff -a_nodata 0 --config GDAL_DATA "Config location" -a_ullr ...
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1answer
168 views

Transform an image with projection EPSG:4326 to EPSG:3857

I have an image with known boundary and projection EPSG:4326 and want to overlay it to openstreetmap using Leaflet.js. I have tried using function imageoverlay, but the image is not aligned with the ...
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34 views

getting started designing satellite projection raster

How do I get started designing a map with a satellite projection like this:http://bl.ocks.org/joyrexus/6619251. So far using d3 I've created a map of North Africa w/ topojson and tiles from Mapbox but ...
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50 views

d3.js Projection for Washington DC area

I'm making a small thematic map of the Washington DC area using d3.js. Everything I've tried "tilts" the square of DC. Is there a d3 projection that will put DC at the right angle? ...
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1answer
91 views

Map scale factor when converting from Mercator to Equirectangular

Lets say I have a map in Mercator projection, and I know top and bottom latitudes: topLatitude = 80; bottomLatitude = -55; I also know width and height of a map: width = 800; height = 500; I want ...
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1answer
56 views

Define Projections for layers with multiple locations in MXD's

# Script to use Layers in MXD source file paths to locate and redefine projections import arcpy, glob, os, sys, arcgisscripting mxd = arcpy.mapping.MapDocument("N:\MXDs\_ThomaKL\MXD GPS ...
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1answer
174 views

How to overlay Image to openstreetmap using leaflet.js

I want to overlay a wide range satellite image onto openstreetmap using leaflet.js. The satellite image is in Equidistant Cylindrical Projection. This is how I initiate the layer. ...
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2answers
69 views

Redefining point shapefiles in MXD that have no projection and are located in different folders using ArcPy?

# Script to use Layers in MXD source file paths to locate and redefine projections import arcpy, glob, os, sys, arcgisscripting from arcpy import env, mapping path = os.getcwd() env.workspace = ...
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2answers
55 views

Alaska Series E projection in ArcGIS for Desktop?

I am trying to digitize a scanned map that appears to be in the Alaska Series E projection. I have also seen this referred to as Modified Transverse Mercator. While this projection is listed as ...
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2answers
237 views

Convert a geotiff web-mercator into an azimuthal equidistant projection

I have a geo-referenced tiff file, in the web-mercator projection; and I need it converted to an azimuthal equidistant projection. I'm new to GIS and can't figure out how to do this. I'm open to ...