New answers tagged

2

What defines which projection is a polygon based upon, and therefore which projection should apply to it? For these vertices, are the right polygons the left or the right ones? That depends on what purpose the polygons are going to used for. If their areas matter, then you should build them in an equal area projection like Albers. If 90 degree ...


7

First install QGIS plugin "Affine Transformation" from Plugins > Manage and Install Plugins.. Then start editing and navigate to vector > Geoprocessing Tools > Affine Transformation. Add your latitude value in 'y+' as encircled in the screen shot.


1

A couple things might be happening here. You have a transparency on the layer (unlikely). You have a stretch type defined in the symbology for the raster. This might be standard deviation: Set it to None and see if that makes any difference.


0

If the county map is in EPSG:2237, better leave it that way. DO NOT use Set Layer CRS to change it, that will corrupt your data. If you did, change it back. Better use Save As ... for vector data and Raster -> Projections -> Warp for rasters. Both need another filename and a different target CRS. If you are unsure, set the PROJECT CRS to EPSG:3857, ...


2

In ArcGIS you can use batch processing to run the re-projection tool on a large dataset. If it doesn't work on rasters than you can use the model builder to achieve the same thing by using iterators as shown here. QGIS also has a batch processing interface but I haven't used it myself, so I'm not sure how effective that is. Your best bet might be to just ...


1

Yes, they will be square in both projections! Breaking it down: UTM stands for Universal Transverse Mercator. From the Wikipedia article: The Universal Transverse Mercator (UTM) conformal projection ... i.e. UTM is "conformal." As for what "conformal" means, again from Wikipedia: Conformal, or orthomorphic, map projections preserve angles ...


1

Fixed! - but this required a bit of luck. I was able to deduce what projection the shapefiles were actually in (The .prj file was incorrect). I then replaced the .prj file above with a .prj file from a correctly projected shapefile and I was able to get everything back to normal. Thanks for the help, Adam's comment gave me a clue.


1

There's a reason UTM projections don't extend to infinitive and engulf the whole globe. As you move further away from the UTM's central meridian the distortion becomes more and more apparent. In the case of a transverse Mercator projection the distortion, as its a conformal projection, is applied equally both in the X and Y axis, therefore your angles ...


2

The transverse Mercator Projection is conformal and preserves angles. So the square should still be a square. Area will change though.


2

Between the two standard paralllels, the projection surface (the cone) is below the ellipsoid surface, so features must be reduced in size to fit on the cone. Above and below the standard parallels, the conic surface is above the ellipsoid so features must be enlarged to fit on the cone. One illustration is here.


2

Think of map projections as the best way possible to preserve: Area Shape Distance Direction All of these cannot be preserved perfectly at the same time. So a map projection such as the Lambert Conformal Conic best preserves those 4 attributes in mid-latitude regions. Regarding the two lines you are asking about (the parallels), these lines are the ...


1

If the shapefiles were created with QGIS, you could look into the .qgs file with a text editor. Otherwise, you can run ogrinfo -al -so filename to get the extent of the data. If it is between +/- 180/90, you can take EPSG:4326 as first chance; else it is a projected CRS. If you can identify a point (x;y) from the shapefile in Google Maps or other ...


1

When you know the original coordinate system you just can copy and rename existing prj files. But I guess that is the problem.


1

There are a few open source implementations of GeoPackage that you can take a look at here: https://github.com/ngageoint/GeoPackage GeoPackage iOS is available via pod install for iOS. GeoPackage Android is available via gradle for Android. GeoPackage Java is available via the maven central repository for java based desktop applications. GeoPackage JS ...


2

The proj string does not contain an EPSG code. You can use EPSG:4269 or +proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs. Some softwares try to guess the EPSG code from the string, and sometimes they fail, and treat it as a custom CRS. EPSG:4269 has degrees as units, and is not a projected coordinate system, but rather a geographic coordinate ...


3

Well, your projection is "longlat", ellipsoid "GRS80" and datum "NAD83", so the data is unprojected and in decimal degrees. This is why is projected is returning FALSE. If you want your data to be projected you first need to choose a projection then use spTransfrom to reproject it. Since we know nothing about your data, like where it is, it is difficult to ...


3

To expand on FelixIP: the coordinates seem to be wgs84 coordinates, that is if you set them as wgs84 with epsg 4326 then they will show up probably correct.


1

from pyproj import Proj, transform P3857 = Proj(init='epsg:3857') P4326 = Proj(init='epsg:4326') x,y = transform(P4326, P3857, lon, lat)


1

A very simple method is to put up a custom transverse mercator projection centered on the center of your study area: +proj=tmerc +lat_0=51.4 +lon_0=7 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs This works for about +/- 15┬░ of longitude. On longitudinal larger areas, a Lambert projection with one or two standard parallels would ...


2

If you're looking for an established projection and you don't mind accuracy to around 2 meters, I would go with EPSG::3006 This assumes your data is in the SWEREF99 datum, but the difference between that datum and WGS84 is very slight.


0

The original canopy rasters have a nodata value of 255 ( not zero) outside of the exact 3-degree extent. You can check that with gdalinfo on command line, or inside QGIS with Rightclick on the layer -> Properties, Metadata tab, Properties section. So it works for me with: gdal_merge.bat -n 255 -a_nodata 255 -of GTiff -o F:/Karten/Geotiff/NLCD/out.tif ...


0

Try to check No data value = Zero, and see if that succeed, as shown below If it is not zero, then replace the zero pixel value with value of pixel. Another option, would be to go to the Transparency tab, and add 0 as an Additional no data value or the pixel value of it is not Zero.


1

You must understand the logic of the Python version of GDAL. With a raster with the same projection (EPSG:3857) from osgeo import gdal data_set = gdal.Open("test.tif") # Getting the Spatial Reference System (returned in Well Known Text(WKT) format) projInfo = data_set .GetProjection() projInfo 'PROJCS["WGS 84 / Pseudo-Mercator",GEOGCS["WGS ...


1

If the output from gdalinfo file_name.tif is to be believed, it looks like the C++ implementation assumed your datum was WGS84 and filled out the rest of the WKT for you, although there shouldn't be an entry for both PROJCS and GEOGCS. It's hard to tell for certain without digging into the gdal source code and libraries.


4

the anomaly has been identified and is currently under investigation. It is not systematic as far as we know. Please report this kind of anomaly to the Copernicus help desk. Thanks S├ębatien CLERC S2 Mission Performance Center


0

Check the other granules in the scene from which 33UXP is taken. If it is something systematic, it should affect all granules (in zone UTM33).


5

I've downloaded these granules and notice the same shift. It appears to be geographic processing error on ESA's behalf. I've never encountered a shift like this before. The image metadata is the same for both, which means some error occurred before the Level 1-C product. (the 100*100Km granules have already been processed, for more information look here) I ...


1

http://www.bev.gv.at/portal/page?_pageid=713,1572954&_dad=portal&_schema=PORTAL notes that the Austrian DEM is in MGI Lambert projection. https://www.data.gv.at/katalog/dataset/b5de6975-417b-4320-afdb-eb2a9e2a1dbf provdies the data in a 3 GB large Geotif file. This should be correctly georeferenced to EPSG:31287, and is free of charge. Some ...


1

QGIS and ArcGIS will both convert directly between two projected coordinate systems. Internally, there may be some extra conversions to WGS84 or latitude/longitude on the input or output CRS but you don't need to handle it yourself. Please note that UTM is part of a projected coordinate system and a UTM zone can be based on many different geographic ...


2

Your grid currently lacks projection information. Hence the line Coordinate System is '' in the output. With proper projection information, the output would start (for example) like: Coordinate System is: PROJCS["UTM Zone 4, Northern Hemisphere", ... It is important to understand the difference between assigning a projection and reprojecting. Using the ...


1

You can go straight from NAD 1983 State Plane California -> UTM => export to .xyz. No need to go to WGS84. When you reproject to UTM, make sure you deal with the Datum correctly if it is NAD27.


0

It seems the projections are different. The first one in WGS84 and the second is in meter maybe in UTM Zone 36 since the landuse is located in Kenya. Try to project the first one to UTM projection. and see if they overlay each other. You may need to re-define the projection of the second one to UTM, if necessary.


2

What version of QGIS, first? I'm using 2.8, and I loaded a layer that has a proper projection/coordinate reference system (CRS). My project is now using that CRS (in my case, MGA Zone 55, 28355). I can tell that by looking in the lower right corner of the QGIS window, or going to project properties. If I choose 'Vector' -> 'Research Tools' -> 'Vector ...



Top 50 recent answers are included