gdal_grid<\/a>\u00a0pour ne prendre pour chaque pixel qu\u2019un seul point en entr\u00e9e. La m\u00e9thode consiste \u00e0 premi\u00e8rement cr\u00e9er un CSV, puis un VRT et utiliser ce fichier comme source de gdal_grid.<\/p>\nex.\u00a0gdal_grid -a nearest:radius1=1:radius2=1:nodata=-9999.0 -ot Float32 -a_srs EPSG:2154 -txe 1074000 1079000 -tye 6325000 6330000 -outsize 1000 1000 -l grid grid.vrt grid_out.tif<\/code><\/p>\ntraitement en batch<\/strong><\/p>\n1\u00e8re \u00e9tape<\/strong>\u00a0: conversion des XYZ en CSV avec cr\u00e9ation de VRT associ\u00e9<\/p>\nex. de script<\/p>\n
#!\/bin\/bash<\/code><\/code><\/p>\n<\/code><\/code>#Lecture de la r\u00e9f\u00e9rence spatiale
\necho “Input spatial reference EPSG (exemple: for WGS84 enter 4326, for Lambert93 2154, for L2E 27572) : ”
\nread c_EPSG<\/p>\n<\/code><\/code>#traitement des fichier en batch
\nfor IFile in *.xyz # modifier ici en cas d’autre format
\ndo
\nBASE=`basename $IFile .xyz`
\nOFile=${BASE}.csv<\/p>\n<\/code><\/code>#ajout d’une ligne d’ent\u00eate “X Y Z”
\nsed ‘1i\\X Y Z’ $IFile > $OFile<\/p>\n<\/code><\/code>#remplacement du caract\u00e8re espace par une tabulation
\nTFile=”Temp”
\ntr ‘ ‘ ‘\\t’ < $OFile > $TFile
\nmv $TFile $OFile<\/p>\n
\n<\/code>#cr\u00e9ation du fichier VRT
\nOFileVRT=${BASE}.vrt
\necho \"<OGRVRTDataSource>\" > $OFileVRT
\necho \" \u00a0 \u00a0<OGRVRTLayer name=\\\"$BASE\\\">\" >> $OFileVRT
\necho \" \u00a0 \u00a0 \u00a0 \u00a0<SrcDataSource>$OFile<\/SrcDataSource>\" >> $OFileVRT
\necho \" \u00a0 \u00a0 \u00a0 \u00a0<GeometryType>wkbPoint<\/GeometryType>\" >> $OFileVRT
\necho \" \u00a0 \u00a0 \u00a0 \u00a0<LayerSRS>EPSG:$c_EPSG<\/LayerSRS>\" >> $OFileVRT
\necho \" \u00a0 \u00a0 \u00a0 \u00a0<GeometryField encoding=\\\"PointFromColumns\\\" x=\\\"X\\\" y=\\\"Y\\\" z=\\\"Z\\\"\/>\" >> $OFileVRT
\necho \" \u00a0 \u00a0<\/OGRVRTLayer>\" >> $OFileVRT
\necho \"<\/OGRVRTDataSource>\" >> $OFileVRT
\ndone<\/code><\/p>\n<\/div>\n2\u00e8me \u00e9tape<\/strong>\u00a0: conversion des VRT (avec leur CSV) en TIF<\/p>\non utilise gdal_grid,ex. de script<\/p>\n
#!\/bin\/bash<\/code><\/code><\/p>\n<\/code><\/code>#Programme pour interpoler des fichiers de points XYZ stock\u00e9s en CSV\/VRT
\n#selon diff\u00e9rents algorithmes et param\u00e8tres.
\n#le fichier grid en sortie est stock\u00e9 en TIF
\n#puis r\u00e9\u00e9chantillon\u00e9 selon la r\u00e9solution voulue.<\/p>\n<\/code><\/code>#Jules Fleury – SIG\u00e9o\/CEREGE
\n#avril 2013<\/p>\n<\/code><\/code>#Lecture de la r\u00e9f\u00e9rence spatiale
\necho “Input spatial reference EPSG (exemple: for WGS84 enter 4326, for Lambert93 2154, for L2E 27572) :”
\nread c_EPSG<\/p>\n<\/code><\/code>#Traitement des fichiers en batch
\nfor IFile in *.vrt # modifier ici en cas d’autre format
\ndo
\necho “Processing $IFile”
\nBASE=`basename $IFile .vrt`
\nOFile=${BASE}.tif
\nval_nodata=-9999 #valeur pour nodata<\/p>\n<\/code><\/code>#Traitement du fichier en utilisant l’algorithme Nearest
\ngdal_grid -a nearest:radius1=0.5:radius2=0.5:nodata=$val_nodata -ot Float32 -a_srs EPSG:$c_EPSG \u00a0-l $BASE $IFile $OFile<\/p>\n
\n<\/code>#r\u00e9-\u00e9chantillonage du fichier en sortie
\nressize=10 #valeur de r\u00e9-\u00e9chantillonage
\nOFileRes=${BASE}_$ressize.tif #fichier r\u00e9-\u00e9chantillon\u00e9 en sortie
\ngdalwarp -tr $ressize $ressize -r cubic $OFile $OFileRes
\necho \"Done\"
\ndone<\/code><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"On suppose dans cette proc\u00e9dure que nos donn\u00e9es constituent un maillage r\u00e9gulier et qu\u2019il n\u2019est pas n\u00e9cessaire de faire d\u2019interpolation. Le fichier ASCII XYZ est compos\u00e9 de trois colonnes X, Y et Z, ex. 880000 6340000 828 880025 6340000 831 880050 6340000 833 880075 6340000 835 Proc\u00e9dure avec ArcGIS 1-Changer l\u2019extension du fichier en .txt … Continue reading “Conversion ASCII XYZ en MNT”<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17,12,7,10],"tags":[],"class_list":["post-140","post","type-post","status-publish","format-standard","hentry","category-arcgis","category-gdal-ogr","category-geo-traitements","category-sig"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/posts\/140","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=140"}],"version-history":[{"count":5,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/posts\/140\/revisions"}],"predecessor-version":[{"id":333,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=\/wp\/v2\/posts\/140\/revisions\/333"}],"wp:attachment":[{"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=140"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=140"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sigeo.cerege.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}