Questions tagged [well-known-text]
Well-known text (WKT) is a text markup language for representing vector geometry objects on a map, spatial reference systems of spatial objects and transformations between spatial reference systems.
433
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Getting coordinates from geometry in PostGIS
This line:
SELECT geom
FROM myLayer.geom
will return a hex value.
How would I get decimal values, which is a human-readable coordination?
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votes
6
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Visualising WKT geometry string in QGIS
Is there a simple tool in QGIS to graphically visualise geometry formatted as text?
Example geometry:
POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 6337246,571178 6337246))
Result:
A ...
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votes
14
answers
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Online WKT and GeoJSON viewer
I once found a great but simple webpage that has a drop-down with several text-based GIS formats such as GeoJSON and WKT, and a text box to copy/paste your data. The feature is then drawn on a world ...
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votes
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answers
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Calculating area in km² for Polygon in WKT using Python
I have polygons in WKT that looks like this
POLYGON ((24.8085317 46.8512821, 24.7986952 46.8574619, 24.8088238 46.8664741, 24.8155239 46.8576335, 24.8085317 46.8512821))
I would like to calculate the ...
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votes
1
answer
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Where can I find the WKT standard or reference?
I had a little confusion about the representation of a geometry as well-known-text (WKT). I was searching for the WKT Specs to search for the exact representation, but I did not find the Standard. Is ...
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17
votes
6
answers
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Converting between Esri Geometry and WKT using ArcObjects?
It seems like there is no means of converting an ArcObjects geometry to the Well-Known Text representation (and vice versa) in ArcGIS ArcObjects API. The only thing I was able to find is conversion to ...
- 10.3k
17
votes
2
answers
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views
Creating CSV with geometry as WKT in QGIS (with choosing field delimiter)
Is there a way to choose the field delimiter when exporting a CSV with geometry as wkt in QGIS?
I have a shapefile with donut holes and I'd like to export it as a CSV. It's for a partner whose DB ...
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16
votes
4
answers
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views
What is the best way to programmatically convert between WKT and Proj4 string?
Some shapefiles have a .prj file associated with it, and the .prj file contains the projection info of the shapefile in the format of WKT.
Sometimes I need to convert WKT to proj4 string, and ...
- 261
15
votes
4
answers
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Converting geometry to WKT using ArcPy?
I would like to be able to convert a single feature (or potentially many features) in an ArcGIS layer into Well Known Text (WKT) format during a geoprocessing operation using Python and ArcPy (no non-...
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votes
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Converting shapefile to WKT
I'm trying to convert a shapefile into the simple Well-Known-Text (WKT) format in the example below (from http://en.wikipedia.org/wiki/Well-known_text).
MULTIPOLYGON (((40 40, 20 45, 45 30, 40 40)),
((...
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15
votes
2
answers
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Seeking online WKT editor?
We need to do are very simple administrative boundary drawings over a (insert fav map here) via some website.
Our requirements are:
click to create points which then form a polygon
drag existing ...
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14
votes
6
answers
3k
views
Is there a way in QGIS 3 to get a selected feature WKT?
In QGIS 2.x, I used the getWkt plugin: https://github.com/hugoledoux/QGIS-getWKT to get a WKT of a selected feature.
But that plugin isn't present in QGIS 3.x. Was that capability built into core ...
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14
votes
2
answers
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Loading WKT polygons into QGIS
I have downloaded a file showing the status of the National Broadband Network. The CSV file contains a field "Development Shape", which contains
"POLYGON ((153.101112401 -27.797998206, 153.097860177 ...
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14
votes
1
answer
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Understanding the format: WKB from WKT and how to convert the first into the latter [closed]
I don't understand which kind of format I have my data. The column name is wkb_geom, so I supposed that data were in WKB format, but then I was checking around and I couldn't find example of it. Data ...
- 315
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votes
1
answer
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Converting geoalchemy2.elements.WKBElement to WKT
I have a geoalchemy2.elements.WKBElement that comes from a query on a Postgres/PostGIS view. I want to convert this to WKT, or otherwise encode it so that it is (Geo)JSON serialisable. How can I ...
- 8,718
12
votes
6
answers
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WKB to WKT JavaScript function
Turns out json isn't so good at transporting binary data. But with HTML5, XHR2 is now capable of transferring blobs cleanly. I'm looking to transfer binary geometry (to save bandwidth) and decode it ...
- 802
12
votes
5
answers
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Looking for a pythonic way to calculate the length of a WKT linestring
I was quite unsatisfied with Calculating Length of Linestrings in WGS84 in Miles. It kept me wondering if there is a more convenient, Pythonic way to calculate the length of a WKT linestring according ...
- 6,838
12
votes
2
answers
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Quick way to get WKT from a GeoDataFrame's geometries in GeoPandas?
Is there a quick way to produce a column/series containing the WKTs of all the geometries in a GeoPandas GeoDataFrame?
I got around this using the apply function (see example below), but I just ...
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11
votes
6
answers
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Converting WKB to WKT
How can I convert WKB to WKT form?
I stored coordinates in WKB but now I want to display it using WKT form.
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11
votes
3
answers
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Is there any efficient way to convert GeoJSON to WKT?
I want to use ST_GeomFromText() to load vector data to PostGIS. However, I don't know how to convert from GeoJSON type to WKT.
N.B. I know I can use OGR2OGR to upload the GeoJSON directly, but I just ...
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votes
4
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How are ESRI WKT projections different from OGC WKT projections?
Does anyone know the precise list of differences between ESRI WKT and OGC WKT projection format strings?
I know there are various tools to help convert from ESRI WKT to OGC WKT, including GDAL ...
- 934
10
votes
5
answers
6k
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WKT for EPSG:4326 with LON 0 to +360 instead of -180 to +180
I have GRIB2 files that seem to be in a projection similar to EPSG: 4326, except that instead of longitude between -180 and +180 it is between 0 and 360.
My intention is to get these files into ...
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10
votes
2
answers
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Converting KML files for use with Python library Shapely
I am trying to get a KML-file (wijken.kml) into Shapely. The KML-file is validated against the proper XML schema, so I guess the input is correct.
Routes I have tried:
1) Converting to WKT or WKB ...
- 335
10
votes
1
answer
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Help with PostGIS polygon geometry - non-closed rings
I've picked up a copy of the super-wicked book 'Python Geospatial Development' by Erik Westra (Amazon link), and I'm working through it. Currently, it's teaching me to load GSHHS coastline data from a ...
- 193
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votes
1
answer
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views
Differences between OGC and ISO WKT/WKB specification?
Are the OGC-Simple feature access and the ISO (ISO/IEC 13249-3:2011 "Information technology - Database languages - SQL multimedia and application packages - Part 3: Spatial") significantly different (...
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votes
2
answers
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How to return WKT of entire polygon with shapely?
Im learning to use shapely and have two shapefiles--forest, and basins. The two shapefiles clearly intersect (basins is completely within forest). But the way I've gone about it only gets the feature ...
- 315
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votes
1
answer
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What's the proper format for WKT linestrings when importing into QGIS?
I'm trying to run the following test CSV through the Delimited Text plugin as WKT data:
oid,Line
1,LINESTRING((45.554194 -122.686101, 45.433001 -122.762632))
2,LINESTRING((45.432505 -122.598327, 45....
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votes
2
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What's this PROJ4 string in WKT?
I have this projection in PROJ4:
+proj=tmerc +lat_0=41.836944 +lon_0=-87.684722 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs
What's the WKT translation?
I saw this site: http://cfconventions.org/...
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8
votes
2
answers
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Converting geometry to WKT format by using QGIS Expression
I have a gpkg file and I am changing the geometry to wkt format by using expression geom_to_wkt( $geometry ) in the Field Calculator.
The output looks like this in the image. The geometry type is not ...
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8
votes
2
answers
4k
views
How to get WKT from a QgsGeometry object?
How can I get the wkt from a geometry object in python?
I'd like to be able to do something like the following:
from qgis.core import *
import qgis.utils
layer = qgis.utils.iface.activeLayer()
for ...
- 261
8
votes
1
answer
2k
views
Export geography field from SQL for use in GIS
I currently have a table in SQL server management studio (2012) with a geography column.
It definitely has valid spatial data, as I can view it in SSMS:
What I want is to export the data as a ...
- 565
8
votes
1
answer
6k
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PostGis vs Oracle Spatial 11g performance
I am having a performance issue updating a table in Oracle Spatial 11G while converting 63,000,000 points to WKT format. I also made a comparison with Postgres. Both Postgres and Oracle run in two ...
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votes
5
answers
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Converting WKT to SHP?
I have a text file containing exactly this:
POLYGON ((6.2973716 48.98613 1772.1, ...many other Long Lat Altitude values ... ))
And only this. It seems to be just like a WKT geometry of a polygon. But ...
- 10.3k
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votes
4
answers
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views
Converting WKT to GeoJSON with Leaflet
I have a point-type WKT geometry column in a MySQL table storing the location of some stores.
I want to display it on a Leaflet map on my website. I've found plenty of tutorials for doing this on ...
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7
votes
3
answers
4k
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Determine if a polygon intersects itself in OpenLayers
I let the users draw polygons and then I try to save them out to the SQL Server 2008 SQLGeography field, but it is giving me an error:
Error 24200: The specified input does not represent a valid ...
- 173
7
votes
3
answers
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.NET library to convert KML to WKT?
Anyone know of a free OpenSource .NET library i could use to convert KML to WKT?
I know i can use openlayers and there are many JavaScript possibilities, but i need to do this on the back-end.
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7
votes
2
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How to read csv with WKT geometry in Arcmap?
I have found several parcels I need on a county map viewer. However, the only option to download any of the data is found on a click context menu to "Copy selection as csv" which gives me this:
HGID,...
- 544
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votes
2
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Convert WKT coordinate reference system to PROJ4
I'm currently working on a better support of LAS 1.4 file format in the rlas R package. In LAS 1.4 format the CRS of the point cloud can be stored as a WKT string. For example this is what I read from ...
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votes
1
answer
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Export geometry to WKT using pyshp
Is there a straight method to export shapefile geometry (polygon) to WKT using pyshp module for python?
I was looking for something similar to OGR's .ExportToWkt() method, but it seems like there's ...
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votes
1
answer
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Understanding EPSG in WKT
I notice several EPSG codes in one WKT. At the first glance it almost is non-intuitive to see so many EPSG codes linked to a single EPSG.
Can someone explain each line of the following WKTs for EPSG:...
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votes
1
answer
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Parameter values to create a vector grid with 1km x 1km cells?
I created a shapefile from WKT in QGIS using the values from this link.
I want to create a vector grid with 1kmx1km cells but I can't figure out what values need to be set for the X and Y parameters. ...
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votes
1
answer
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projection/pyproj puzzle, and understanding SRS format
I have a shapefile that has a .prj file, with the following wkt contents:
PROJCS["NAD_1927_StatePlane_New_York_West_FIPS_3103",GEOGCS["GCS_North_American_1927",DATUM["D_North_American_1927",SPHEROID["...
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7
votes
1
answer
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views
Where are the WKT types CIRCULARSTRING, COMPOUNDCURVE etc actually defined?
I'm trying to find the actual definition of the curve types supported by PostGIS in WKT.
PostGIS's documentation refers to the " SQL Multimedia Applications Spatial specification":
The SQL ...
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7
votes
1
answer
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loading a CSV with an embedded GeoJSON polygon geometry in QGIS
This open data portal offers download as CSV file. For larger datasets, that's the only way to download the whole dataset in one go. The CSV format is pretty creative: the polygon geometry is in ...
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votes
1
answer
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Is there a limit to the number of polygon points you can export to CSV in QGIS 2.4?
Using QGIS 2.4
I am currently importing a csv file with ~30,000 polygons (polygons in WKT format). I also have a United States shapefile. I have used the Clip function to get only the polygons that ...
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votes
4
answers
4k
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Getting correct WKT result to 4 decimal places using PostGIS
I'm using PostGIS version 2.3. I want to get the SW and NE corners of a bounding box, corrected to 4 decimal places.
Right now I have this to retrieve the SW and NE corners from my geometry column:
...
- 3,289
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votes
3
answers
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How to get WKT for various Spatial Reference Systems?
I need to provide WKTs of spatial reference systems in the APIs provided by GDAL/OGR.
Is there some specific place where I can look for WKTs of the spatial reference systems that I'm working with? Or ...
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6
votes
2
answers
6k
views
Adding field with geometry in WKT format in QGIS
I have a shapefile with polygons and want to add an attribute field with the WKT in QGIS 3.4.
The function geom_to_wkt() in the Field Calculator isn't working and I don't know how to do it. Any ideas?
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votes
2
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gdalwarp cutline without using a shapefile
I'm currently working with gdalwarp to split some tiffs.
gdalwarp -cutline file.shp -dstalpha -of GTiff image.tif split_image.tif
I wanted to know if I can use an other source rather than use a ...
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votes
1
answer
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How to generate WKT geometries from true type font glyphs (python)
Does anyone know of a library or tool ( preferrably Python)to convert true type font glyphs into polygonal shapes (for testing GIS algorithms)?
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