ExportToBMP

Récapitulatif

Exports the page layout or data frame of a map document (.mxd) to the Microsoft Windows Bitmap (BMP) format.

Discussion

BMP files are simple, native Windows raster images. BMPs can store pixel data at several bit depths and can be compressed using the lossless RLE method. However, in general, BMPs are much larger than formats such as JPEG or PNG. They do not scale as well as vector files and may appear blocky or jagged when increased in size. BMPs generated from the data view in ArcMap can be generated with an accompanying world file so that they can be used as georeferenced raster data. BMPs without a world file are commonly used as inserted graphics in other documents.

To export a single data frame instead of the entire page layout, pass a DataFrame object to the function's data_frame parameter. Because data frame exports do not have an associated page to provide height and width information, you must provide this via the df_export_width and df_export_height parameters.

Controlling graphic quality of the generated image differs for page layout exports versus data frame exports. When exporting a page layout, control image detail by changing the resolution parameter. When exporting a data frame, keep the resolution parameter at its default value, and change the df_export_width and df_export_height parameters to alter image detail. The height and width parameters directly control the number of pixels generated in the export file and are only used when exporting a data frame. Images with larger numbers of pixels will have higher image detail. For most page layout exports, the default parameter values should generate good results and nice looking export images on the first try. For data frame exports, you may need to experiment with the df_export_width and df_export_height values a few times before getting the result you want.

World files are not generated for page layouts; a referenced data frame must be provided or the export will fail.

Refer to the Exporting your map topic in ArcGIS Help for more detailed discussions on exporting maps.

Syntaxe

ExportToBMP (map_document, out_bmp, {data_frame}, {df_export_width}, {df_export_height}, {resolution}, {world_file}, {color_mode}, {rle_compression})

Paramètre	Explication	Type de données
map_document	A variable that references a MapDocument object.	MapDocument
out_bmp	A string that represents the path and file name for the output export file.	String
data_frame	A variable that references a DataFrame object. Use the string/constant "PAGE_LAYOUT" to export the map document's page layout instead of an individual data frame. (La valeur par défaut est PAGE_LAYOUT)	Object
df_export_width	A number that defines the width of the export image in pixels for a data frame export. df_export_width is only used when exporting a data frame. Exporting a page layout uses the map document page width instead of df_export_width. (La valeur par défaut est 640)	Integer
df_export_height	A number that defines the height of the export image in pixels for a data frame export. df_export_height is only used when exporting a data frame. Exporting a page layout uses the map document page height instead of df_export_height. (La valeur par défaut est 480)	Integer
resolution	A number that defines the resolution of the export file in dots per inch (DPI). (La valeur par défaut est 96)	Integer
world_file	If set to True, a georeferenced world file is created. The file contains pixel scale information and real-world coordinate information. (La valeur par défaut est False)	Boolean
color_mode	This value specifies the number of bits used to describe color. 24-BIT_TRUE_COLOR —24-bit true color. 8-BIT_PALETTE —8-bit palette. 8-BIT_GRAYSCALE —8-bit grayscale. 1-BIT_MONOCHROME_MASK —1-bit monochrome mask. 1-BIT_MONOCHROME_THRESHOLD —1-bit monochrome threshold. (La valeur par défaut est 24-BIT_TRUE_COLOR)	String
rle_compression	This value represents a compression scheme. NONE —Compression is not applied. RLE —Run-length encoded compression. (La valeur par défaut est NONE)	String

Exemple de code

ExportToBMP example 1

This script opens a map document and exports the page layout to a BMP file using default values for all options.

import arcpy
mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
arcpy.mapping.ExportToBMP(mxd, r"C:\Project\Output\Project.bmp")
del mxd

ExportToBMP example 2

This script will export a single data frame instead of the entire page layout, similar to exporting from data view in the ArcMap application. The default values for df_export_width and df_export_height are 640 and 480. By passing larger values for these parameters, we are able to produce an output image with higher detail. Setting world_file = True generates a georeferenced world file in the same directory as the output file.

import arcpy
mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Transportation")[0]
arcpy.mapping.ExportToBMP(mxd, r"C:\Project\Output\ProjectDataFrame.bmp", df,
                          df_export_width=1600,
                          df_export_height=1200,
                          world_file=True)
del mxd