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
vote
1answer
311 views

How does Arc project data without spatial reference?

I have a raster file downloaded from here. When I load it into ArcMap, it says the data is missing spatial reference, and that it can be drawn in ArcMap but not projected. Nevertheless, using the ...
1
vote
1answer
47 views

NAD83 2011 AZ central projection

I am having trouble getting GDAL to read a file geodatabase with data projected in NAD83(2011) State Plane Arizona Central FIPS 0202. I have developed the following code: # standard imports import ...
0
votes
1answer
136 views

Creating a spatial reference in arcpy from projection name

I am using ArcGIS 10.2.2, Python 2.7. I want to create a spatial reference from the name of a projection, e.g. NAD_1983_BC_Environment_Albers, using the arcpy tool ...
4
votes
3answers
933 views

Is NAD 83 the same as EPSG:4326?

I'm getting mixed messages about these projections. For example -Is this projection below, NAD 83, 4326? GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983", ...
5
votes
1answer
92 views

If Geographic Coordinates are unprojected coordinates, how can GIS softwares display such unprojected data on a plane?

I have been using ArcGIS and QGIS regularly for about 2 years now, and just recently I was struck by this new thought. If a data set in say, in ArcMap, has been georeferrenced with a Geographic ...
1
vote
1answer
644 views

Converting distance between nautical miles and degrees using ArcObjects?

We have a certain functionality developed that: Will check for a tolerance value (this input is given by the user as NM); Buffer a polygon by that value (all polygons are in WGS-84); Iterate through ...
0
votes
1answer
37 views

gdal_translate or gdalwarp to define projection

Which of these is the best approach to define (aka. set) a projection for a tiff? 1) gdal_translate -a_srs EPSG:32182 in.tif out.tif 2) gdalwarp -s_srs EPSG:32182 -t_srs EPSG:32182 in.tif out.tif ...
6
votes
1answer
82 views

Lambert conformal conic isn't actually conformal?

Mathematically a conformal map has the property that the Jacobian of the transformation is a scaled version of a rotation matrix. The transformation involved in a spherical Lambert conformal conic ...
0
votes
1answer
852 views

Geographic Transformations using ArcPy vs. Coordinate Systems used by ArcGis online basemaps

I have three shapefiles with undefined projection, but I know which one was used (Lisboa_Hayford_Gauss_IPCC). I need to first Define Projection. It works. I then need to transform it to WGS_1984, so ...
0
votes
1answer
106 views

SRID, Shape2SQL and SQL Server 2008r2 query

I'm using Shape2SQL to load the Ordinance Survey's Meridian 2 map into SQL Server 2008r2 (which is working very smoothly and painlessly). According to this page ...
4
votes
1answer
98 views

How to use SRTM Global DEM for Aspect calculation?

I need to derive a raster representing aspect for North America (from STRM data, originally in geographic lat/long). In most projections, true north is only map north along eg the central meridian so ...
1
vote
0answers
50 views

project hdf file with geospatial_lat and lon in batch process

Is there any way that I can do a batch process in projecting hdf files wherein I could get and include only the geospatial_lat and lon in the batch script since every hdf file have different ...
3
votes
1answer
480 views

Which Geographic Transformation to use for WGS_84 to D_Sphere?

I have a shapefile for world countries and I want to reproject it from GCS_WGS_1984 to Sphere_Eckert IV. However, it asks for Geographic Transformation; it says this is optional but it is required in ...
0
votes
1answer
91 views

How to get projection data (.prj) of raster image using GDAL/OGR?

I start with a boundary shape-file (think U.S. states) in lat/long that I convert to some projection, and then rasterize the result as a .tif. What I need now are the raster coordinates of the ...
2
votes
3answers
173 views

Best Projection for Getis Ord Gi* Statistic Analysis

I am about to calculate the Getis Ord Gi* statistic for some rasters whose extents are global. In choosing a projection, do I want to preserve distance (e.g. equidistant) to obtain accurate ...
1
vote
1answer
31 views

Why prj2epsg cannot resolve PostGIS SRText?

In many places I have seen people referring to http://prj2epsg.org (here, here). I have used this service too, however, the service cannot uniquely identify an EPSG code alway. I understand that it ...
2
votes
0answers
34 views

Finding centroids for icosahedral gnomonic projection?

I've been trying to create an icosahedral gnomonic projection, like this example by Jason Davies or this one (the Fisher projection). The method that I initially used was using the centroid of each ...
2
votes
0answers
59 views

Reprojecting PostgreSQL/PostGIS data as it streams in?

I have a postgres/postgis database. I would like to reproject those data coming to me in 4326 to 32736. For those tables with lat long info in wgs84 (4326) I have set the geom to 4326. Then I have ...
0
votes
1answer
82 views

Difference between WGS_1984_UTM_33N and GCS_WGS_84

What is the difference between: a map that has a projected coordinate system of WGS_1984_UTM_33N, a geographic coordinate system of GCS_WGS_1984, and a datum of D_WGS_1984 a map that has no ...
2
votes
0answers
30 views

Thiessen polygons extend outside of extent of projection

I'm working on a geological project on the past position of continents (in ArcMap 10 Service Pack 5, build 4400). The tool I'm creating in Model Builder uses Create Thiessen Polygons and all input ...
2
votes
1answer
84 views

Defining projection using readOGR if the shapefile doesn't have it?

I think that by using readOGR to import a shapefile renders worthless to put proj4string to the script since if any coords are available in the shapefile, it will be transported through the readOGR. ...
1
vote
0answers
136 views

How does OpenLayers 3 handle coordinates?

Ol3 always uses the flatCoordinates because obviously it needs 2d-coordinates as the screen is only 2-dimensional. But how does OL3 calculate the flat representation? For example if my view’s ...
0
votes
0answers
27 views

ArcGIS Online no spatial reference

My intention is to georeference an image so as to create a Swipe Map in AGOL. First, I add my control points, rectify, then analyze before attempting to share and finally publish in AGOL. The other ...
1
vote
0answers
48 views

set Default projection in postgis table

I've set the SRID 4326 for a table having geometry column, but when i insert a geometry without SRID, i get an error because no SRID specified is interpreted as -1 or 0, so how i can set a default ...
1
vote
3answers
822 views

PRJ file for Stereo70 S-42 projection?

I receive lots of Romanian maps with the projection STEREO70 with Datum "S-42 for ROMANIA". I have only found the "Stereo 1970.prj" by ESRI, and when I open the maps with my GIS software the ...
3
votes
1answer
77 views

How to manually add spatial reference information for FEWS rainfall data in ArcMap?

I am trying to match rainfall data from USGS/FEWS to coordinate locations of survey households in Uganda, so I will need to be able to project the rainfall data. So far, I downloaded the dekadal RFE ...
1
vote
0answers
38 views

Zonal geometry output in ArcGIS

Is there a way to specify the coordinate type in Zonal geometry output in ArcGIS? I am trying to perform zonal geometry on a raster and in the resulting output, the XCENTROID and YCENTROID are in ...
1
vote
1answer
250 views

Openlayers 3 WMS custom projection wrong extent

I'm using Openlayers 3 to view a WMS-layer from a Mapserver in EPSG:3006, see the code: Proj4js: Proj4js.defs["EPSG:3006"] = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m ...
0
votes
0answers
24 views

Multiple Satellite Swatch processing for 1 years worth of data

I have a file of several scans per day for one year. I am using the OMINO2 product from the Aura platform. I am tasked with creating an automated process to: 1) Extract the sub-data set within the ...
0
votes
0answers
82 views

How to set raster projection in R

I am new to R and grib files. library(raster) I have a "grd" file in and I am trying to set the coordinates to polar stereographic projection r <- raster("p190001.grd") # class : ...
0
votes
0answers
8 views

Lots of NaNs in reprojecting LSASAF to WGS84

I have a LSASAF file that has LOFF 1808 COFF 308 LFAC = 13642337 CFAC = 13642337 and the standard Euro dimensions NC = 1701 NL = 651 But when I try to translate the range col=1..1701, lin=1..651 ...
1
vote
1answer
48 views

Is EPSG:3857 the correct projection for my PDF in Lambert Conformal Conic projection?

Given the following NEATLINE from the results of gdalinfo on my Geospatial PDF: NEATLINE=POLYGON ((-1340591.5297333347 -260482.28440259479,-1340591.0579001249 1878014.4171204455,3081498.0723039531 ...
1
vote
0answers
133 views

LiDAR dataset displaying 500 meters to the east of correct position

Why does my LIDAR dataset show up ~500 meters to the east of the correct position even though a spatial reference/coordinate system is provided? Some background: The LIDAR data were downloaded from ...
0
votes
0answers
54 views

ogr2ogr re-projection produces empty shapefile

I use the following to re-project a shapefile to EPSG 4326 using ogr2ogr: ogr2ogr -s_srs "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" -t_srs "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" ...
2
votes
1answer
58 views

QGIS reprojecting .ecw file in EPSG:23032

I opened the .ecw file with qgis but I found that the ortophoto is 340 mt northern and 150 mt eastern the topographic map. How can I move the ecw?
7
votes
1answer
186 views

What are pros and cons of forcing square pixels on reprojection?

I am using Erdas Imagine 2014 to reproject 4-band raster data from GRS 1980 NAD83 Lambert Conformal Conic (ft) to UTM GRS 1980 NAD83 North UTM Zone 11 (m). Unlike ArcGIS, Erdas provides the option to ...
2
votes
0answers
50 views

Reverse parameters of a projection map

I'm user of a soaring simulator named "Condor Soaring". This simulator is at the center of a community of enthusiastic people who build sceneries (landscapes) which represents quite accurately real ...
0
votes
2answers
186 views

How to change different projections of feature classes in geodatabase to one projection in new geodatabase?

I want to create a script that iterates through feature classes with different projections in a geodatabase and exports them into a new geodatabase, all with the same projections. What I want is to ...
0
votes
1answer
224 views

How to convert latitude, longitude to EPSG 3857?

I'm looking to study the math involved to see how a given latitude and longitude in decimal degrees can be converted to epsg 3857. Can anybody point to a good reference or a possible python/c/c++/java ...
1
vote
1answer
83 views

How to use a different projection than EPSG:3857 with CartoDB or Leaflet?

I have data that is accurately positioned with the NAD 83 MTQ Lambert EPSG:3798 projection. If I reproject this data in EPSG:3857 (web mercator) the markers are no longer positioned accurately on the ...
1
vote
1answer
33 views

Change Projection

I am a little bit lost here. working in QGis 2.8, OS X 10.10. I have a polygon shp in the CRS EPSG: 21781, CH1903 / LV03 and a point file in EPSG: 4326, WGS84 How would I work with these ...
0
votes
0answers
29 views

Adding IF statement for Batch Projections

How do I add an "if" statement that will: 1) List all .tif files and their projections within the input directory 2) Copy all .tif and .shp files that are of the same projection from the input ...
1
vote
1answer
68 views

ArcGIS 10.2.1 projection Issue - Everything shifted west 50 m

I just completed hand-digitizing features on some NAIP (NAD83) imagery as a shapefile (NAD83...or that's what I thought I was doing). The coordinate system for the dataframe was NAD83, but now when I ...
4
votes
2answers
2k views

How to “calculate” distance-to-ground of all 18 OSM zoom levels?

Assuming I'm building a 3D solution with the "world" being mapped to global geo-data supplied by OSM / Cloudmade... think http://www.webglearth.com but with completely different goals and use-cases. ...
3
votes
1answer
115 views

Obtaining length of non projected feature (gcs_wgs_84) in meters instead of decimal degrees?

I could not find a post which answered to my problem and I hope I didn't miss it, in case I did I apologize. I'm working with Arcgis 10 and I have a multiple lines feature with gcs_wgs_1984 ...
0
votes
0answers
91 views

Change SHP Projection to display on Google Map

I'm pretty new to GIS but not to programming, so sorry if this was already asked. I didn't find a solution not sure if I didn't quite understand everything about Projections and so on. I have a GIS ...
1
vote
0answers
49 views

ESRI/Mapinfo MGA56 prj vs QGIS MGA56 prj

I am trying to understand why the degree unit is different between ESRI/Mapinfo and QGIS: ESRI/Mapinfo ...
3
votes
3answers
598 views

Which projection is best for mapping the contiguous United States?

If I wanted to project latitude & longitude data for the contiguous United States (the United States excluding Alaska and Hawaii), which projection would I use? I prefer more accurate distances ...
0
votes
0answers
31 views

How can I create a warp mesh to match two close but not identical datasets together?

I have two datasets for Mars. One of them is the Mars Viking color mosaic, the other the Mars Global Surveyor black and white imagery. When I overlay the two datasets, it becomes obvious that the ...
3
votes
2answers
4k views

What are the units of the calculated area from a raster in decimal degree

I'm trying to calculate area for a raster file which contains 2 layers (0 for unsuitable habitat and 1 for suitable). It's been calculated successfully but I don't know what is the unit of the ...