New answers tagged

1

The data's bounding box is defined with geographic coordinates. I guess this is what caused the confusion. The data itself, however has the EPSG code 27700, hence the element <DefaultCRS>urn:ogc:def:crs:EPSG:6.9:27700</DefaultCRS>. This means, that the data will be in EPSG 27700 unless otherwise specified. In this case, EPSG 4326 would be a ...


2

Just in case you want the distance along the parallel of latitude (and not the shortest distance) between two points at a given latitude, distance = r * (longitude 2 - longitude 1) with longitude in radians and where r, the radius of the parallel of latitude, is r = R * cosine latitude where R is Earth radius.


4

You can do both: At Using customized Coordinate System for Archaeological site data I have explained how to set up a local CRS based on the origin of the local system. The data in the local CRS remains untouched, and can still be edited. Or you can use the affine transformation plugin to shift the data into real world coordinates. This has the disadvantage ...


1

The Zoomify source in OpenLayers 3 has indeed a different coordinate system than in OpenLayers 2. However, both coordinate systems do not make much sense. Ideally, the origin would be in the top left corner, and y coordinates would increase from top to bottom. For now, all you can do is configure OpenLayers 3 to do an automatic transform of your coordinates....


1

The answer depends on what you are interested in and therefore what you mean by 'earth's surface'. The Geoid is the equipotential surface (in terms of gravitational potential). The ellipsoid is a geometric approximation of the irregular land-sea (physical) surface. Given the irregularities even in the physical surface, no ellipsoid can ever do a perfect job. ...


0

If a coordinate reference system (CRS) identifies itself as an ellipsoid (spheroid in Esri-speak) and there's no datum information, there are no available transformations. Ellipsoids are used for multiple datums and geographic CRS. If you have the area of interest, you can find out what geographic CRS have been used in the area. If there are multiple ones, ...


0

The EPSG database http://epsg-registry.org/ contains also "Area of Use" descriptions. From the documentation: Area of Use The area of use is a description of the geographic applicability of certain entities. It is applied toCoordinate Reference Systems, Datums and Coordinate Operations (Conversions, including Map Projections,and ...


0

What is the epsg code of your data that ArcGIS recognizes? It should be 4024 for the Krasovsky ellipsoid without datum. Try to set it to the data if it is not recognized and have a look if ArcGIS has a transformation then. Otherwise it would be best to have a look for reference points when you are not sure about the correct positions. The ellipsoid, ...


1

Locate your shapefile. The error message says it's in: "D:\CLASSES\Debugging_andErrorHandlingLab\Data\TravisCountyAustinTxx.mxd\parks.shp" The .MXD can't be a folder, so it's definitely not there. Perhaps it's in the same folder as the MXD: dataset = r"D:\CLASSES\Debugging_andErrorHandlingLab\Data\parks.shp"


1

LOTS OF ERRORS were fixed --.spatialRefernce (no good) .extent(no good), lyrlist, had too many arguments--FIXED import arcpy mxd = r"D:\CLASSES\Debugging_andErrorHandlingLab\Data\TravisCountyAustinTxx.mxd" mapdoc = arcpy.mapping.MapDocument(mxd) dataset = r"D:\CLASSES\Debugging_andErrorHandlingLab\Data\TravisCountyAustinTxx.mxd" spatialref = arcpy....


0

As a comment you provided a line of ArcPy code that I just tested using: import arcpy arcpy.CreateFishnet_management("C:/Temp/test.shp","223122.902847 4244274.58422","266744.967575 4410255.40647","0","0","6","6","447614.673105 4372719.14612","LABELS","wrs_dec_va_proj15033","POLYLINE") This reported an error: Traceback (most recent call last): File "C:\...


0

As #mkennedy and @AndreJ suggested, I tried simply georeferencing each map of the Spezialkarte der Osterreichisch-Ungarischen Monarchie on a modern 1:25000 map of Croatia: the results are precise enough for my goals. I attach a picture so that I can give you an idea. I also tried using @Wernfried Domscheit projection, but the map is georeferenced in a ...


1

Same as mkennedy, I suggest to georeference against a map of today, like OpenStreetMap or Google satellite. Road junctions, railway crossings and river bridges have not moved over the time. On the other hand, surveying has improved a lot. Keep in mind that they had no satellite imagery, and many things were just collected by sight. The reference meridian of ...


0

Alternatively, in QGIS save as CSV dialog, under the Geometry heading there is a tick box 'Include z-dimension'. Tick this box and select point. From the layer options heading, select XYZ for the geometry. Tested using QGIS 2.14.3 Essen


1

How are the Z values measured? Depending on what the z values are referenced to, you may be able to use them without 'reprojecting'. If they are referenced to the ellipsoid, you'll need to recalculate them. Here is an online calculator for this purpose: http://apps.linz.govt.nz/coordinate-conversion/index.aspx?Advanced=1 Here is a table of examples of ...


0

SR-ORG:14 as specified below, although technically not projected, meets your question statement. I suspect from your question you are a little confused and what you require is a Geographic Coordinate System. > GEOGCS["GCS_WGS_1984", > DATUM["WGS_1984", > SPHEROID["WGS_1984",6378137,298.257223563]], > PRIMEM["Greenwich",0], > ...


0

Have a look at this page: PROJ.4 - General Parameters I think at least partly the projection string is this one: +proj=latlong +pm=17d39'37.5"W +a=6376033 +b=6356354 +rf=324 I am not a geodesist, so I don't know if this definition is complete. But it could be a starting point. btw, you can list available datums, projections, etc by cs2cs -lP cs2cs -le ...


0

In addition to what AndreJ answered: I can susbtitute the saving to a new layer part when I use the "Define Current Projection" tool (Vector > Data Manegement Tools). This means I don't need to produce more data by saving to a new shapefile. And QGIS will still recognize the right coordinate system also when I load the shapefile into other *.qgs projects....


3

There is no projection that can be consistent without distortion at global scale. This is the main reason of having so many projections. The distortion will always exist in shape, area, distance and direction. You can choose a projection that can preserve one of the four parameters, but the other three parameters will be distorted. You can refer to ...


0

I know it is dated in May but if you don't reproject it to UTM NAD 83, then your ArcMap will run very slowly !! so if you reproject then it will run smoothly and I agree with Christina as well.


0

I know it is a little late to answer but I had a similar problem and wanted to convert my Raster tab file to a esri world file (tiff + tfw). I could not use command files as it is blocked from my IS department.I tried to convert from FME but it could not read my tab file (which had a Pt4 line missing).So I worked it out myself = See step by step guide on ...


1

Before you do anything else, go Settings -> Options -> click the 'CRS' tab and set the default CRS to EPSG:27700 (British National Grid). You have two problems. Firstly, from the coordinate you circled in red in your illustration it's obvious that QGIS does not recognise that your OS Street View tiles are georeferenced. To fix this, from the 'georeferencing ...


2

Both EPSG codes you mention have identical parameter values. QGIS takes just the first that fits the values. If you experience any problems, use Set Layer CRS to assign the EPSG:3006, then save to a new filename. QGIS creates a separate .qpj file where the EPSG code is stored explicitely.


1

Comparing the GADM dataset for the phillipines with an Openstreetmap background, I agree that the GADM dataset is totally off. Trying the local datum of Luzon 1911 or PRS92 does not fit better: Luzon and PRS92 (in red) are identical. The borders shoud follow the great roads, as seen in the OSM background as dotted lines. You can use the VectorBender ...


0

Thank's a lot @xunilk ! I change the coordinates of the points I want in my layer with a QgsCoordinateTransform instance and now it works ! Here is the way I did (you cans translate the comments if you don't understand what i'm doing...): # On commence par creer une liste des points qgis delimitant la zone de chantier points = [] # On ajoute maintenant ...


0

If you're pregenerating the hex information, as your question suggests, you could use my R package dggridR to generate the hexagons' boundaries. dggridR uses some rather complicated maths to tile the entire Earth with non-overlapping, equally-sized hexagons. Here's an example of how you might use dggridR to create the grid you need: #Include libraries ...


0

You need to use QgsCoordinateReferenceSystem and QgsCoordinateTransform classes. I tried out next code to transform polygon vector layer of next image from EPSG: 32612 to EPSG: 4326. layer = iface.activeLayer() crsSrc = QgsCoordinateReferenceSystem(32612) crsDest = QgsCoordinateReferenceSystem(4326) xform = QgsCoordinateTransform(crsSrc, crsDest) ...


0

Here's a windows app I wrote to do the job. 2GDA94.zip


0

I'm not 100% sure, but I think you may have to set the coordinate system of the canvas as well. There is a post here that indicates this: http://gis.stackexchange.com/a/151867 For example, the answer there shows code like the following: mycrs = QgsCoordinateReferenceSystem(32611) iface.mapCanvas().mapRenderer().setDestinationCrs(mycrs) I would suggest ...


2

If you have to deal with the whole United States, you should use one of the Contiguos projections: ESRI:102003 USA_Contiguous_Albers_Equal_Area_Conic ESRI:102004 USA_Contiguous_Lambert_Conformal_Conic ESRI:102005 USA_Contiguous_Equidistant_Conic Alaska and Hawaii should then be treated separately.


2

It is the result of the differences between the Proj4 parameters in QGIS and GRASS GIS: 1) If you look at the definition of the EPSG:20137 projection, the Proj4 string is: +proj=utm +zone=37 +ellps=clrk80 +units=m +no_defs 2) The GRASS7 commands of the Processing Toolbox use a) the script /../python/plugins/processing/algs/grass7/Grass7Algorithm.py to ...


2

There are many coordinate reference systems (CRS) which could be used for the San Francisco area depending on what you are doing with the data. UTM zone 10 North is designed for medium scale purposes and maintains shapes and angles. San Francisco area is in State Plane California zone 3 (III). That's designed for large scale purposes. State Plane zones are ...


0

The weak point seems to be at the single point. If you import it with Add delimited text, it is only a temporal layer, and has no CRS information written to disk. However, the clipping tool does not look into QGIS layer settings, only what CRS information is written on disk. So you better save the point to a shapefile with EPSG:3357, then proceed with the ...


1

I found the projected coordinate system has linearUnitName property, and angularUnitName property is empty, and for the geographic coordinate system is just the opposite. so can get unit by follow codes. sr = arcpy.Describe(fc).SpatialReference unit = sr.linearUnitName if unit == '': unit = sr.angularUnitName


2

The normal to the ellipsoid is the vector orthogonal to the tangent to the ellipsoid at that point. This will not point to the center of the earth except at the equator and the poles. The gravity vector is orthogonal to the geiod and varies from the ellipsoidal normal by an amount called the deflection of the vertical. Which is usually expressed in the ...


1

The metadata in the CDL dump indicate the data is using the M3IOConvention, from the Models-3/EDSS API, which I assume you already knew based on your comments about interpreting the metadata. Checking the netCDF-Java library (used by Panoply) source code for handling that convention, I see that the Earth radius is hard-coded as 6370.0 km. Whether using that ...


2

Both definitions have identical values. Just the names are different, and there is little you can do about it. You can run gdalsrsinfo on both files, and they return: PROJ.4 : '+proj=tmerc +lat_0=0 +lon_0=33 +k=0.99995 +x_0=200000 +y_0=-3500000 +ellps=WGS84 +units=m +no_defs ' This is the format that QGIS uses for the projection definition, without any ...


1

Exactly. I used coutry boarders and I projected them into MGI_M34 as well. I did try now to add 750000 to the east-coordinates and subtracted 5000000 from the north-coordinates. this is what is written in Wikipedia... this is the result: afterwards I displayed them and this comes out: so the points are in Germany now... ;) any idea what that could mean?...


2

In most cases, the saved GCP file will be of no value. It works to georeference a raster that has no CRS, addressing pixels and lines. The usual workflow is to save the raster in a format that stores the CRS information inside the file (like geotiff). Using a vrt file would be possible too, but needs some handwork. Once the geotiff has its own CRS ...


1

You probably want the OSTN02 NTv2 grid file, which we just put into ArcGIS around version 10.4 or later. Download the file here: https://www.ordnancesurvey.co.uk/business-and-government/help-and-support/navigation-technology/os-net/ostn02-ntv2-format.html In an Explorer window, browse to: C:\Program Files\ArcGIS\Desktop10.1\pedata\ntv2 and create a new ...


9

It appears to be decimals of a minute, as FelixIP suggested. So it could be written 68 35.067 N, 123 54.817 W and recognized in Google Earth. It's actually not too uncommon to see this notation. I plugged in a couple of points this way, and they appear on the river course.


2

Why does it appear squashed? In the TIFF viewer, the map is in the correct proportions. When a Google map of the same area is overlaid, it matches on-the-ground features almost exactly. Google Maps uses a spherical Mercator projection of WGS84 lat/longs, called WGS84 Web Mercator. Earth is not a sphere, so the Web Mercator projection stretches as a ...


1

We are dealing with this issue right now and are looking at the DotSpatial library for .NET since it appears to have support for NADCON and NTv2. https://github.com/DotSpatial/DotSpatial


0

This is a more complex problem because the "coordinate formula" describe only an ideal case. If you have a raster clipped by a shapefile the formula will not work. However, the issue can be totally solve with Python code. To test my approach I used a little raster (20 x 20) to easily corroborate the results. For this situation, a shapefile was used to ...


1

you could create thiessen polygons around each raster value (using euclidian allocation tool). Then you can extract the value for each point using extract value to point. Note that distance analysis at global scale has two problems: 1) there is a rupture in the map (usually between -180 and + 180) and the scale is not constant.


1

This model assumes the world is spherical, but earth's radius changes with the latitude. If the distance covers about 1/10 of a degree, and Earth's radius ranges from 6353-6384km, then the error can be over 400m. This might cause 10km to come out as 9km if you are aggressively rounding.


2

For javascript you can use proj4.js. Its conversion function is called proj4.


0

In order to get geographic coordinates from a Shapefile with projected spatial reference, the geometries need to be reprojected when working with OGR. I tried to avoid this at first, because I'm working in a custom spatial reference system and I'm not sure about the reprojection parameters. When I look at the reprojected data in a GIS, they seem to be ...


0

For you, what is the difference between geographic coordinates and projected coordinates ? From ESRI GeoNet: Projected Coordinate System vs. Geographic Coordinate System: A Geographic Coordinate Systems is defined by a 3-D surface and is measured in latitude and longitude. A Projected Coordinate systems refers to data that is defined by a flat 2-D surface ...


2

SQL Server Spatial Tools is a CLR assembly that you can add to your database to assist with a number of operations that didn't come built in with the original release of SQL Server spatial objects. It has a set of functions to do similar operations as those found in Oracles SDO_CS. There is a projection example in the source code section, though it doesn't ...



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