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Optimizing Adobe Illustrator Documents with MAPublisher for Geospatial PDF Export

Adobe Illustrator documents with GIS data can be exported to georeferenced PDF files thanks to the MAPublisher Export Geospatial PDF feature. A geospatial PDF is an Adobe Acrobat file that contains geospatial coordinates. With coordinates, users can view and interact with the PDF to find and mark location data. MAPublisher exports all the MAP Attributes data in an Adobe Illustrator document into the geospatial PDF. Attribute values can subsequently be accessed and searched in Acrobat 9 (and 8 with limitations).

In order to ensure the best interoperability and geospatial PDF output results from your MAPublisher documents, the following work practices are recommended:

Convert document color mode to RGB

To ensure predictable color results, it is highly recommended to convert the documents color mode to RGB prior to exporting to Geospatial PDF. This is advisable especially if generating geospatial PDF documents to be used in conjunction with the PDF Maps app for IOS devices. The document color mode can be changed in Adobe Illustrator through File > Document Color Mode > RGB Color.

Colour mode

Crop data to the required extents using the MAP Vector Crop Tool

Remove any extraneous data not required for the geospatial PDF document by cropping the map using the Vector Crop Tool (located in the Adobe Illustrator Toolbar). If necessary, exclude data from being cropped by locking the its the appropriate layers.

Vector crop

Remove unnecessary layers

Delete any map layers that are not required for the final PDF map document. This may include raster layers, hidden layers, and layers that are outside the mapping extent or art board. Not only will this decrease file size, it will also simplify your layers list and improve organization. Delete layers in the MAP Views panel or the Layers panel.

delete selection

Preserve data contained within sublayers

If your document contains map data organized within sublayers it will be necessary to reorganize/move this data to it’s parent layer if you wish to preserve it when converting to and from geospatial PDF. This is necessary because data contained on sublayers are forced into their parent layer by the Adobe Illustrator PDF exporter. Layers are also required for importing a geospatial PDF back into MAPublisher in order to assign a schema.

Remove unused attribute information

Data sets, especially those available through various data portals and government agencies can contain attribute information not suited or required for our mapping need, or perhaps we are only interested in the geometry of the data for representational purposes. In this case it is advisable to delete any attribute information that does not fulfill a purpose as this will unnecessarily increase the resultant file size. Select your data, open the MAP Attributes panel, and click the Edit Schema button. You may delete and organize your attributes using this panel.

Edit attribute schema

Assign MAPublisher attributes to Adobe Illustrator Object names

This recommendation is not necessary but may be useful in some cases. In MAPublisher the #Id attribute column is a unique identifier MAPublisher uses internally to associate attributes with unique pieces of art. By default the art will have a name of “path” or “compound path” however it may be desirable to tag the object with a unique identifier from an existing attribute column for the purposes of making it easier to differentiate art objects within the Acrobat tree list, for example.

To do this we can use the “Apply Expression” option in the MAP Attributes panel. Simply designate the #Name column as the “Apply to” option while entering the name of the attribute column you wish to derive the attributes from as the “Expression”. For example in the screeshot below we are renaming the art objects contained in the #name column with values stoed in the “ROUTE” column with the results being reflected in the artwork listed in Illustrator Layers panel.

Use the Simplify Line Tool

Reduce the number of vertices available in MAP Line and Area layers by using the Simplify Line tool (located on the MAPublisher toolbar). This differs from the Adobe Illustrator Simplify Path tool because it takes into account X and Y coordinates. The proximity value or simplification tolerance is based on the vertical difference between the begin-end line and points off a line, not the distance between anchor points on the line.

Simplify lines

Geospatial PDFs derived from or include images should be generated as 72 DPI

This has particular relevance when dealing with geospatial PDF files, especially those generated with Geographic Imager. When a 200 DPI (dots per inch) georeferenced image is converted to a geospatial PDF, the image will be embedded in the PDF as a 200 DPI image. However, when displayed by PDF viewing applications such as Acrobat or Illustrator it will appear as a 72 DPI image. Due to this, on export, MAPublisher converts the referencing to 72 DPI format since it must be imported back as 72 DPI

Geospatial PDF at 72 DPI

Following the above recommendations should help ease the transition of your MAPublisher documents to and from geospatial PDF.

 

How to Download USGS Maps for your iPhone, iPad or iPod Touch

If you haven’t read about it yet, USGS topographic maps for the United States are now available for download on the Avenza PDF Maps Library.

USGS topographic maps are great for viewing, reference and recreational uses such as hiking, fishing or exploring. You can download the maps beforehand (in cellular range or over Wi-Fi) and use the GPS capability (of the iPhone and iPad Wi-Fi+3G) to locate yourself on the map. These 1:24,000 scale maps include the lower 48 states, Alaska, Hawaii and the District of Columbia. All of the maps are in geospatial PDF format. Best of all, majority of the maps are lightweight meaning they download and process quickly on your device.

The process of getting USGS maps on your iOS device is simple

First, download and install the app if you don’t have it yet. Open the PDF Maps app. In the map list screen, tap the + button (Add Map) in the top-right corner.

open the PDF Maps app

Then tap the From Avenza PDF Maps Library button.

open the PDF Maps Library

The app connects to our PDF Maps Library server and lists several categories. Tap the USGS Topographic Maps category.

Tap USGS

The maps are categorized by state and area. We’ll retrieve a topographic map of a part of the city of Tucson, AZ. In the list of the U.S. states, tap Arizona.

Tap Arizona

In the preview map of Arizona, area grids are represented by the dashed gray lines. These area grids contain all of the available topographic maps categorized further by area name. Tap the area grid that contains Tucson.

Tap Tucson

Scroll down the list and tap Tucson East. This will take you to a preview of the map before the last step of downloading it.

Tap Tucson East

A preview of the map is shown. Finally, tap the Download 3.3MB button to download the Tucson East map. The PDF file size is listed as 3.3 MB.

download the map

The device automatically returns to the PDF Maps app where the Tucson East map will be downloading. After the download is complete, the app will automatically process and render all the tiles you’ll need to explore the map. This will only take a few minutes.

PDF Map downloading PDF Map processing

When the processing is completed, it will show it’s total size (18.1 MB) that includes tiles for all of the different zoom levels. Tap the Tucson East map to load it.

Done processing Explore map

These USGS maps and other maps on the Avenza PDF Maps Library are fully georeferenced and compatible with PDF Maps. Still have questions about PDF Maps? Read our support page or send us your questions. Stay tuned for more content.

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