shape file reading
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Hi Hernan I downloaded this shapefile directly via the browser. Indeed it won’t load, the type of shape file returned is self longAt: 33 bigEndian: false -> 577660194 where it should have answered an Integer between 0 and 31 shapeType "position 32, Integer between 0 and 31, Little Endian" ^shpBytes longAt: 33 bigEndian: false No idea what could be the cause – apparently the header of the file (the first 100 bytes) is not ok...
Hans You mean some types are missing? Because I get this error when I try to read some SHP files: "Types > 20 are not yet accounted for" I wrote this script to reproduce: | shpE legend urlRoot urlESRIFilePrefix urlESRIFileShp urlPath response fileRef | Once downloaded: | urlESRIFilePrefix urlESRIFileShp shpE | Maybe it's related with the fact they are encoded as koi8r? I checked with Zinc downloading first from the browser: | shpFile |
Cheers, Hernán |
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Well, it appears that simple direct downloading does not download the real shapefile. Taking care to actually get a shapefile,
the result loads without problems. ne_110m_populated_places.shp is a PointShape with 243 shapes (points). If you display it on a Form (#displayMorphic) you
won’t see much (243 hardly visible dots). With an application for vector graphics (Roassal?) that can read & display the vector data we would get much nicer maps... Hans
From: Baveco, Hans <[hidden email]>
Hi Hernan I downloaded this shapefile directly via the browser. Indeed it won’t load, the type of shape file returned is self longAt: 33 bigEndian: false -> 577660194 where it should have answered an Integer between 0 and 31 shapeType "position 32, Integer between 0 and 31, Little Endian" ^shpBytes longAt: 33 bigEndian: false No idea what could be the cause – apparently the header of the file (the first 100 bytes) is not ok...
Hans You mean some types are missing? Because I get this error when I try to read some SHP files: "Types > 20 are not yet accounted for" I wrote this script to reproduce: | shpE legend urlRoot urlESRIFilePrefix urlESRIFileShp urlPath response fileRef | Once downloaded: | urlESRIFilePrefix urlESRIFileShp shpE | Maybe it's related with the fact they are encoded as koi8r? I checked with Zinc downloading first from the browser: | shpFile |
Cheers, Hernán |
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Hi Hans,
Roassal has support for loading OSM raw data and OSM tiles (map backgrounds) (WGS84 projection). See https://www.youtube.com/watch?v=6zoGIsQaGUo&t=429s. We've also experimented with animations as well: https://www.youtube.com/watch?v=sMB7DG-lbiU; we've also tried in the past to work out of GRASS-produced rasters for complex geographic analysis, such as runoff flooding, projected on osm tiles. Regards, Thierry Le ven. 5 juin 2020 à 14:27, Baveco, Hans <[hidden email]> a écrit : > > Well, it appears that simple direct downloading does not download the real shapefile. Taking care to actually get a shapefile, the result loads without problems. > > ne_110m_populated_places.shp is a PointShape with 243 shapes (points). If you display it on a Form (#displayMorphic) you won’t see much (243 hardly visible dots). > > > > With an application for vector graphics (Roassal?) that can read & display the vector data we would get much nicer maps... > > > > Hans > > > > From: Baveco, Hans <[hidden email]> > Sent: vrijdag 5 juni 2020 12:44 > To: Any question about pharo is welcome <[hidden email]> > Subject: [Pharo-users] shape file reading > > > > Hi Hernan > > > > I downloaded this shapefile directly via the browser. Indeed it won’t load, the type of shape file returned is > > self longAt: 33 bigEndian: false -> 577660194 > > > > > > where it should have answered an Integer between 0 and 31 > > > > shapeType > > "position 32, Integer between 0 and 31, Little Endian" > > > > ^shpBytes longAt: 33 bigEndian: false > > > > > > No idea what could be the cause – apparently the header of the file (the first 100 bytes) is not ok... > > > > Hans > > > > > > > > > > You mean some types are missing? Because I get this error when I try to read some SHP files: "Types > 20 are not yet accounted for" > > > > I wrote this script to reproduce: > > > > | shpE legend urlRoot urlESRIFilePrefix urlESRIFileShp urlPath response fileRef | > > " Download Shapefile resources " > urlRoot := 'https://github.com/nvkelso/natural-earth-vector/blob/master/110m_cultural/'. > urlESRIFilePrefix := 'ne_110m_populated_places'. > urlESRIFileShp := urlESRIFilePrefix , '.shp'. > urlPath := urlRoot , urlESRIFilePrefix. > > #('.shx' '.dbf' '.shp') do: [ : ext | > | url | > url := (urlPath , ext , '?raw=true') asZnUrl. > (response := ZnEasy get: url) isSuccess > ifFalse: [ self error: 'Cannot download file' ]. > fileRef := FileSystem disk workingDirectory / (urlESRIFilePrefix , ext). > fileRef writeStreamDo: [ : stream | > stream nextPutAll: ((ZnByteEncoder newForEncoding: 'koi8r') decodeBytes: response contents ) ] ]. > > > > Once downloaded: > > > > | urlESRIFilePrefix urlESRIFileShp shpE | > urlESRIFilePrefix := 'ne_110m_populated_places'. > urlESRIFileShp := urlESRIFilePrefix , '.shp'. > > " Load and display it in Morphic " > shpE := ShapeEnsemble fromFile: urlESRIFileShp. > > > > Maybe it's related with the fact they are encoded as koi8r? > > I checked with Zinc downloading first from the browser: > > > > | shpFile | > shpFile := 'ne_110m_admin_0_countries.shp' asFileReference. > [ shpFile binaryReadStreamDo: [ : in | > (ZnCharacterEncoder detectEncoding: in upToEnd) identifier ] ] > on: ZnCharacterEncodingError > do: [ nil ]. > > > > > > Cheers, > > > > Hernán > > > > |
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In reply to this post by Hans Baveco
El vie., 5 jun. 2020 a las 9:27, Baveco, Hans (<[hidden email]>) escribió:
I checked and my previous download method was completely wrong. Now switching from ZnEasy to ZnClient to download and it works nicely: | shpE legend urlRoot urlESRIFilePrefix urlESRIFileShp urlPath response fileRef | " Download Shapefile resources " urlRoot := 'https://github.com/nvkelso/natural-earth-vector/blob/master/110m_cultural/'. urlESRIFilePrefix := 'ne_110m_populated_places'. urlESRIFileShp := urlESRIFilePrefix , '.shp'. urlPath := urlRoot , urlESRIFilePrefix. #('.shx' '.dbf' '.shp' '.cpg' '.prj') do: [ : ext | ZnClient new url: (urlPath , ext) asZnUrl; queryAt: 'raw' put: 'true'; numberOfRetries: 2; enforceHttpSuccess: true; downloadTo: urlESRIFilePrefix , ext; get ]. " Load and display it in Morphic " shpE := ShapeEnsemble fromFile: urlESRIFileShp. " List data fields " shpE dataFields inspect. " List all shape records " shpE shapeRecords inspect. " Set the current attribute " shpE attribute: 'NAME'. legend := ColorLegend mapValuesToRandom: shpE valuesOfCurrentAttribute. shpE legend: legend. shpE displayMorphic.
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Please add this to the readme :)
-------------------------------------------- Stéphane Ducasse 03 59 35 87 52 Assistant: Aurore Dalle FAX 03 59 57 78 50 TEL 03 59 35 86 16 S. Ducasse - Inria 40, avenue Halley, Parc Scientifique de la Haute Borne, Bât.A, Park Plaza Villeneuve d'Ascq 59650 France |
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Done! Cheers Hernán El sáb., 6 jun. 2020 a las 3:17, Stéphane Ducasse (<[hidden email]>) escribió:
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