Hi KC, I believe it is the right place for your question, maybe no one could really check it out. While I have not relied on OGR_STYLE on the command line, I have read a lot of practical examples looking for how to create a geoPDF a few days ago. So check out this guides and try to change only the format from PDF to KML
https://spatialthoughts.com/2015/10/25/geopdf-gdal/ http://latuviitta.org/documents/Geospatial_PDF_maps_from_OSM_with_GDAL.pdf For me what worked for PDF was to use feature.SetStyleString(style_string) and add to output data source using python, may work for KML too below a minimal example. I created a KMZ on the project but I used another library for it, not gdal itself but I will provide it here also if it helps . Also I noticed that the PDF Label is not showing up on the result as I expected neither I used the label on the KML so cannot help you on this for now, just the styling and popup on the kml, but if I get any progress I report to you. My Best, Cainã K. Campos import json from osgeo import ogr, osr, gdal import matplotlib.colors as mcolors import simplekml def get_style_rules(): return { "hidrografia": {"color": "blue", "fillColor": "blue", "fillOpacity": 0.6, "opacity":0.5, "weight":0}, "area_imovel": {"color": "yellow", "fillColor": "white", "fillOpacity":0.01, "weight":3, "opacity":0.8}, "apps": {"color": "red", "fillColor": "red", "fillOpacity": 0.3, "opacity": 0.5, "weight":0} } def color_name_to_hex_with_alpha(color_name, alpha=1.0, invert_alpha=False, bgr=False): """ Convert a color name to a hex value with alpha (transparency). Alpha should be a float between 0.0 (fully transparent) and 1.0 (fully opaque). """ try: # Get the hex color code without the '#' and convert to RGBA hex_color = mcolors.to_hex(color_name)[1:] # Scale alpha to 255 and convert to hex alpha_hex = f"{int(alpha * 255):02X}" if bgr: hex_color = f"{hex_color[-2:]}{hex_color[2:4]}{hex_color[:2]}" if invert_alpha: return f"#{alpha_hex}{hex_color}" return f"#{hex_color}{alpha_hex}" except ValueError: return "#000000FF" # Default to black with full opacity if color name not found def create_styled_layer_from_geojson(geojson_data, output_pdf): # Create a temporary file to store the GeoJSON data temp_geojson_file = '/tmp/temp_geojson.json' with open(temp_geojson_file, 'w') as f: json.dump(geojson_data, f) # Open the GeoJSON file with OGR driver = ogr.GetDriverByName('GeoJSON') dataSource = driver.Open(temp_geojson_file, 0) # 0 means read-only if dataSource is None: print('Could not open file') return # Create a spatial reference spatialRef = osr.SpatialReference() spatialRef.ImportFromEPSG(4326) # Assuming WGS84 # Create the output PDF driver driver_pdf = gdal.GetDriverByName('PDF') if driver_pdf is None: print('PDF driver is not available.') return # Create the PDF file output_ds = driver_pdf.Create(output_pdf, 0, 0, 0, gdal.GDT_Unknown) if output_ds is None: print('Could not create PDF file') return output_layer = output_ds.CreateLayer('layer', srs=spatialRef, geom_type=ogr. wkbUnknown) in_lyr = dataSource.GetLayerByIndex(0) lyr_def = in_lyr.GetLayerDefn () for i in range(lyr_def.GetFieldCount()): output_layer.CreateField ( lyr_def.GetFieldDefn(i) ) # Iterate through features and style them for feature in dataSource.GetLayer(): geom = feature.GetGeometryRef() cod_tema = feature.GetField('cod_tema') car_code = feature.GetField('cod_imovel') style = get_style_cod_theme(cod_tema) fillOpacity = style.get('fillOpacity', 0.5) # Apply the style to the feature color = color_name_to_hex_with_alpha(style['color'], style.get("opacity", 0.5)) fillColor = color_name_to_hex_with_alpha(style.get('fillColor', 'none'), fillOpacity) line_width = style.get("weight", 1) # Create a new feature with the same geometry new_feature = ogr.Feature(output_layer.GetLayerDefn()) new_feature.SetGeometry(geom.Clone()) # Set the style of the new feature style_string = f"PEN(c:{color},w:{line_width}mm)" if fillColor != 'none': style_string += f";BRUSH(fc:{fillColor})" style_string += f';LABEL(f:"Arial, Helvetica", s:26pt, t:"{car_code}")' new_feature.SetStyleString(style_string) # Add all attributes to the feature for i in range(feature.GetFieldCount()): field_name = feature.GetFieldDefnRef(i).GetName() field_value = feature.GetField(field_name) new_feature.SetField(field_name, field_value) output_layer.CreateFeature(new_feature) # Destroy the feature to free resources new_feature = None # Close the data sources dataSource = None output_ds = None def create_kmz_from_geojson(geojson_data, output_kmz): # Create a KML object kml = simplekml.Kml() # Iterate through features and style them for feature in geojson_data['features']: cod_tema = feature['properties'].get('cod_tema') style = get_style_cod_theme(cod_tema) # Extract geometry and properties geom = feature['geometry'] properties = feature['properties'] # Create a KML placemark for the feature placemark = kml.newmultigeometry(name=cod_tema) for coords in geom['coordinates']: if geom['type'] == 'Polygon': placemark.newpolygon(outerboundaryis=coords) elif geom['type'] == 'MultiPolygon': for polygon_coords in coords: placemark.newpolygon(outerboundaryis=polygon_coords) # Apply style to the placemark color = color_name_to_hex_with_alpha( style['color'], style.get("opacity",0.5), invert_alpha=True, bgr=True ).upper() fillColor = style.get('fillColor', 'none') if fillColor != 'none': fillColor = color_name_to_hex_with_alpha( fillColor, style.get("fillOpacity",0.5), invert_alpha=True, bgr=True ).upper() placemark.style.linestyle.color = color.replace("#","") placemark.style.linestyle.width = style.get('weight', 1) if fillColor != 'none': placemark.style.polystyle.color = fillColor.replace("#","") # Add attributes as description description = "<br>".join(f"<b>{key}</b>: {value}" for key, value in properties.items()) placemark.description = description # Save KML to a KMZ file kml.savekmz(output_kmz) On Thu, Jul 18, 2024 at 12:51 PM Open Land LLC via gdal-dev < gdal-dev@lists.osgeo.org> wrote: > Hi Everyone, > > I just wanted to ask - Is this the right place to post questions? I put in > a post several days ago, and just want to make sure I'm putting it in the > right place, because I have not posted to this group before. Thank you - KC > > ---------- Forwarded message --------- > From: Open Land LLC <realoptio...@gmail.com> > Date: Mon, Jul 15, 2024 at 9:00 PM > Subject: How to add labels to DEM contour lines > To: <gdal-dev@lists.osgeo.org> > > > Hi everyone, this is my first post. I've also posted this to > https://stackoverflow.com/questions/78751101/labelling-contour-lines-with-ogr-style > > I'm trying to add labels to DEM contour lines. > > I'm working with GDAL 3.6.2. , which I installed using Anaconda . I have > some DEM data from USGS which I wrote as a contour map to a KML file using: > > gdal_contour small.tif /home/ubuntu/node/geotools/contour.kml -i 3.0 > -f KML -a ELEVATION > > When I open contour.kml in vim, I can see that its made up of features > like: > > <Placemark> > > <Style><LineStyle><color>ff0000ff</color></LineStyle><PolyStyle><fill>0</fill></PolyStyle></Style> > <ExtendedData><SchemaData schemaUrl="#contour"> > <SimpleData name="ID">39</SimpleData> > <SimpleData name="ELEVATION">525</SimpleData> > </SchemaData></ExtendedData> > <LineString><coordinates>-89.2626638689733,46.1525006611575 > -89.262663868958,46.1525469572921 -89.2627325352002,46.152622208059 > -89.2628251277396,46.1526266807347 -89.2629177202847,46.1526141000471 > -89.2629982621728,46.1525469573863 > -89.2629982621882,46.1525006612516</coordinates></LineString> > </Placemark> > > Clearly there is a style component available , but I'm not sure how to > work with it to add elevation labels or custom colours. My suspicion is > that OGR_STYLE is used to do things like this ( > https://github.com/OSGeo/gdal/issues/835)(https://gdal.org/user/ogr_sql_dialect.html#ogr-style > ), but I can't find any examples. How can this be done? > > Thank you very much, > > KC > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev >
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