The first concern arises from the fact that several versions\nof the DWG format exist. <\/p>\n\n\n\n The GDAL library used by QGis, is compiled\nwith the libopencad library that manages some of these versions, but\nnot all . You will get a\nmessage such as the following<\/p>\n\n\n\n In the case where the version is\nsupported\nby libopencad you will\nget a window similar to: <\/p>\n\n\n\n Drawing<\/strong>\nSoftware<\/strong>\n\/<\/strong> GIS<\/strong> Software<\/strong>\n<\/p>\n\n\n\n In the previous window we can see the conceptual difference\nbetween\nCAD and GIS software. In the drawing software , the\nobjects are grouped in\n\u00ab\u00a0layers \u00a0\u00bb in this window\n. We must not confuse the layer concept with the GIS layer.\n<\/p>\n\n\n\n GDAL tries to move from one notion to another and\nthat\nis why you have in\nthis\nwindow\na\nproposal for GIS layers built from layers of the DWG drawing file.\n<\/p>\n\n\n\n The first line suggest a 0-FB1-archive\nlayer with 7 entities of linear type . It\ncorresponds to a layer of that name where the designer has placed just the\nlinear objects . For\nthis layer \/ layer there is, a priori, no\nproblem. <\/p>\n\n\n\n Nevertheless, a a little further down, we\nhave a \u00ab\u00a0BORNES\u00a0\u00bb layer with 39 entities but\nwith a \u00ab\u00a0Geometry Collection\u00a0\u00bb type geometry .\nThis, clearly, means that the objects\ndrawn\non this layer are of different types : lines , points, text , etc …\n<\/p>\n\n\n\n GDAL cannot create a single\nGIS-type layer from the layer without losing, eventually, important information.\nFor the time being, QGis does not support layers with different\ngeometries (I believe, only\nGeomedia\nIntergraph\nmanages\nmulti-type geometries). If you select\nTERMS and click OK, you will see\na\nnew layer in the layers panel , but of the DATASET type\n<\/p>\n\n\n\n You will not see any\nentity\non your cartographic\nwindow. Nevertheless,\nif\nyou\nopen\nthe attribute table you can\nsee\nthe contents of this DATASET <\/p>\n\n\n\n You can see\nthat the original layer contained circles and\ntext. Nevertheless, this layer\nis\nunusable\nin\nQGis because no geometry is\nassociated\nwith the layer and, therefore, we cannot display it on the map.\n<\/p>\n\n\n\n Entities<\/strong>\n Content<\/strong><\/p>\n\n\n\n The other problem that arises but,\nusually, when importing data from\nthe CAD software, is how to manage symbology entities. In\nGIS,\nthe symbology is managed\noutside\nthe entities data. It is not stored as data, at the\nmost it can be stored\nin\nseparated files, such as QML or SLD. <\/p>\n\n\n\n In the list of layers shown above you can\nsee\na FAS-hatch- built layer that contains hatches of buildings . <\/p>\n\n\n\n These layers are useless during\nthe integration in a GIS.\n<\/p>\n\n\n\n A<\/strong> workaround<\/strong>\n<\/p>\n\n\n\n Until GDAL can solve all\nthese\ndrawbacks\nhere is a workaround. <\/p>\n\n\n\n You can install and use a free\nprogram to turn DWG files into DXF, before loading them into QGIS.\n<\/p>\n\n\n\n ODA File Converter (Open Design Alliance) allows converting\nthe different versions of DWG to the DXF format. <\/p>\n\n\n\n You can download<\/a> the following<\/a>\nlink<\/a> . <\/p>\n\n\n\n Once installed , when running it, you will get\nthe following window: <\/p>\n\n\n\n You can select\nthe most recent version of the DXF format as it does not pose any\nintegration problem with GDAL and QGIS.\nThe program converts all the DWG files of a\ndirectory , and possibly subdirectories (if\nyou\ncheck\nthe Recursive folders<\/em><\/strong> box ). <\/p>\n\n\n\n Besides, the fact of having a\nfile\nin\na readable format by QGis, the program groups all\nentities in three types of entities : points, lines and polygons\n, plus one Geometry Collection class .\n<\/p>\n\n\n\n Unlike GDAL and Libopencad\n, you will see a reduced number of Geometry Collections.\nOnly the collections that ODA cannot interpret (eg CADAttdef)\nwill remain as collections. <\/p>\n\n\n\n Others, such as the layer TERMINALS we have discussed above,\nwill be converted as points for the texts (with TEXT\nattribute ) and lines for the circles . \n\nThe result , if you load\nthe three layers (Point, LineString and Polygon) will be of the\nfollowing type: \n\n\n\n<\/p>\n\n\n\n A cleaning job to remove drawing artefacts will be\nessential to retain only the data itself:<\/p>\n\n\n\n This can be easily done since the attribute table\ngenerated\ncontains\nthe name of the original layer for each\nentity\n. <\/p>\n","protected":false},"excerpt":{"rendered":" The DWG format is an Autocad proprietary binary format. When we want to load layers in QGis from this format, multiple problems arise. QGis uses the GDAL library to read \/ write external formats , such…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"give_campaign_id":0,"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"sfsi_plus_gutenberg_text_before_share":"","sfsi_plus_gutenberg_show_text_before_share":"","sfsi_plus_gutenberg_icon_type":"","sfsi_plus_gutenberg_icon_alignemt":"","sfsi_plus_gutenburg_max_per_row":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1260],"tags":[],"class_list":["post-8679","post","type-post","status-publish","format-standard","hentry","category-non-classe-en"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p6XU0A-2fZ","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/posts\/8679","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/comments?post=8679"}],"version-history":[{"count":0,"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/posts\/8679\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/media?parent=8679"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/categories?post=8679"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sigterritoires.fr\/index.php\/wp-json\/wp\/v2\/tags?post=8679"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/i0.wp.com\/www.sigterritoires.fr\/wp-content\/uploads\/2019\/05\/81.png?resize=255%2C141&ssl=1\")
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