Collaborating in geospatial context since 2000!

Wednesday, January 25, 2006

ArcMap Scale Bars for Geographic Coordinates

We just had a customer send us a GeoPDF created with Map2PDF for ArcGIS. The map was created using geographic coordinates, and covered an area around 32 degrees North latitude. Map2PDF for Reader was measuring the 12 km scale bar in GeoPDF to be 10 km -- what gives?

The Map2PDF for Reader/Acrobat paradigm doesn't really have a notion of maps in geographic coordinates, per se. We treat all maps as in projected coordinate systems. To resolve our impedance mismatch, we treat ArcGIS geographic coordinate maps as special cases of the equidistant cylindrical projection with a standard parallel passing through the middle of the map. We did this for a couple of reasons. First, since the map author didn't choose an explicit coordinate reference system for the map, there are no Cartesian coordinates to recover. Second, we wanted to make measurements as accurate and useful as possible.

It appears that ArcMap calculates a scale bar for a geographic coordinate map using something like a equidistant cylindrical projection with a standard parallel at the equator, but makes geodesic measurements. Indeed, the customer measuring the scale bar in ArcMap shows 10 km, not the 12 km marked on the map. To get the most functionality out of your GeoPDF coming out of ArcMap, pick a projected coordinate system. If want the look of the geographic coordinate system, pick equidistant cylindrical, and pick a standard parallel in the middle of your area of interest.

Friday, January 20, 2006

New and Improved Maps

There are some new maps in map gallery that are an improvement over the old stuff we had. The show off some of the features built into GeoPDF. Here are some tips to maximize your viewing pleasure.

  1. Got Adobe Reader or Acrobat? Our plugins work with Adobe Reader versions 6 and 7. If you don't have 7, you might want to upgrade to get the latest features. The plugins also work with Acrobat (Standard and Pro) versions 6 and 7. Get Reader

  2. Snarf Map2PDF Regardless of your platform, the plugins are free to download and install. If you've got Acrobat and Reader, get appropriate plugins for both. Installers are geared toward particular versions. Get Map2PDF for Reader. Get Map2PDF for Acrobat. You'll have some fields to fill in on that last one... ;)

  3. Snarf GeoPDF Maps Go to map gallery and, here's the money tip, right click on a PDF's link to save the file to disk. We're working on full viewing in a browser, but it's better external to a browser. Once the map is downloaded, open with the Acrobat or Reader with Map2PDF.

I've looked at the Steller Sea Lion and Dall's Porpoise maps. One of the nifty things about these is that they've been enabled for commenting in Reader. You can mark up these maps in Reader and save the changes... something that you weren't able to do in the past. You can enable commenting in Reader for pretty much any PDF or GeoPDF using Acrobat Pro 7.

A GPS for your Thoughts?

Dan just let me know that we're running a survey about our Map2PDF stuff. Funny how hackers are always the last to know about these things... anyway, some of the preliminary feedback is interesting. Dan is running down some permissions to post some comments here on the blog, and some of the results as well. If you'd like to participate, Click Friend, and Enter!

Wednesday, January 18, 2006

Data Sharing with GeoPDF article in Geospatial Online

Dennis Wuthrich wrote a nice overview of GeoPDF and its usage called Data Sharing with GeoPDFs in Geospatial Solutions. He captured nicely the idea that GeoPDF is a complement to a GIS and a means by which GIS professionals can get data into the hands of anyone anywhere.

Thursday, January 12, 2006

MRFI: Map2PDF Request for Implementation

MRFI (pronounced "Murphy") stands for "Map2PDF Request for Implementation". MRFI is a completely unofficial process by which folks can let us know what sorts of features they'd like to see in any of our Map2PDF products. Send me some email with:

  • title

  • author

  • description

I'll start a new post, and we'll go from there. Eventually, I'd like to evolve it into something like SRFI, from which I so shamelessly stole the idea and name. Blue sky or nitty gritty. The description can be a brief as you like. Of course, I'll withold your name at your request.

Monday, January 09, 2006

New Contact Info

We've got a new email address in our contact sidebar.

Saturday, January 07, 2006

Webmap brings GeoPDF to Australia

Our friends at Webmap are showing how to publish smart, interactive maps in GeoPDF. They've got a great webpage devoted to GeoPDF with some dazzling sample GeoPDFs that show off what it's all about.

Still Here...

Yes, we're still kicking. There's a bunch going on behind the scenes that I hope to be able to share soon...