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Author Archive for Leszek Pawlowicz Page 61 of 79



Saving Money By Using Free Geography Tools Instead Of Geographic Data Services

SlashGeo links to a website that, like a number of others, offers services to convert graphic images and vector data into Google Maps, Google Earth, and Virtual Earth formats. There’s certainly a niche for services like this, especially if you don’t have a lot of background in working with geographic data. But if you have even a little bit of that background, you can save a lot of money by doing it yourself.

1. Converting PDF files to Microsoft Virtual Earth format requires first converting them to a graphic format like JPG or TIF, which you can do with for free with PDFCreator. Next you have to georeference them, assigning coordinates to the individual pixels in the image. I’ll be covering a number of free ways to do that in the future, but for now, it’s enough to say that you can georeference and image with the free GIS program MapWindow, or with MicroDEM. Finally, to convert the georeferenced image to Virtual Earth format, you can use Microsoft’s free MapCruncher utility. Saves about $499 versus outsourcing it, at the cost of a just a little time.

2. For plotting vector data like shapefiles on Google Maps, you can use the free utility Google Map Creator. Need to convert AutoCAD files to shapefile format? There’s a free plugin for MapWindow that lets you do that. Saves you $349 over outsourcing it.

3. Finally, for putting GIS Data into Google Earth format, there are a number of free or cheap options that let you do that. And to convert PDF files into a Google Earth format, use the process outlined above to convert a PDF to an image, and then georeference it. If you need to convert the image from UTM or some other coordinate system to Google Earth’s native coordinate system of latitude/longitude, you can use a free utility like GDALWarp (also to be covered in the future on this blog). You can then use a cheap ($20) utility like Valery Hronusov’s SuperOverlay to convert that image, or any georeferenced image, to a tiled Google Earth format. $20-50 in software costs, at most, versus an outsourced cost of $199-499.

BTW, if you have the need for any of these services, and don’t feel comfortable doing them yourself, email me with your requirements, and I’ll quote you a price that’ll be far less than those listed above ;-).




Simple Guide To Embedding Google Maps "My Maps" On Your Own Webpage

A while ago, I referred to a web-based tool that helps you embed Google Maps “My Maps” data on your website. Digital Geography has a short and simple step-by-step tutorial on how to do that.




The Global Change Master Directory: A "Must-Have" Collection Of Data Links

NASA’s Goddard Space Flight Center in Maryland maintains the Global Change Master Directory, one of the largest (if not *the* largest) collections of links to data I’ve found on the Internet, somewhere on the order of 15,000. While the header refers to “Earth science data and services”, it’s not limiting itself to the traditional definition of “Earth science” there (i.e. fields like geology, geophysics, meteorology, etc.).

The data is initially divided into 14 broad groupings:

Going to these pages, you’ll find the topics broken down further into subtopics, and even sub-sub-topics. For example, under Climate Indicators, you’ll find sub-topics for:

You can also search for data by map, date or location name. This is a “must-bookmark” data resource.




Terrain Slope/Aspect Display And Analysis

In addition to displaying elevation directly, either as terrain or colors, MicroDEM can also display elevation derivatives. Examples include curvature, relief, summits and ridges, but the simplest are probably slope and aspect.

Continue reading ‘Terrain Slope/Aspect Display And Analysis’




Two Fun Cartographic Google Maps Tools

– Dig a hole through the center of the earth from any location, and find out where you’ll come out. Also useful if you’re making an earth sandwich.

– Set off in a constant compass direction from a location, and find out what path you’ll take around the world.

Via GoogleMapsMania.




Mathematica Map Projection Applet

The latest release of Mathematica (Version 6) has the ability to create mini-applets called Demonstrations that interactively illustrate various aspects of mathematics. The Demonstrations website has scores of free Demonstrations that can run in either the full paid version of Mathematica, or in free downloadable player (warning: 80MB download). This site is heaven for math geeks, but there’s also a mapping-related Demonstration called World Map Projections that shows how the 2D-view of the world, and individual countries, changes depending on how you project the 3D world onto a 2D surface.

Continue reading ‘Mathematica Map Projection Applet’




Yahoo Pipes Adds Google Earth Support

Yahoo “Pipes is a free online service that lets you remix popular feed types and create data mashups using a visual editor” (from the Pipes website). They’ve now added support for Google Earth, where they geocode address or location results from a Pipe, and convert them into KML format automatically. See the post on Google Earth Blog for more info.




Elevation And Contour Line Display In MicroDEM – Make Your Own Simple Topo Maps

In earlier posts on MicroDEM, the digital elevation model (DEM) has been displayed in reflectance mode, terrain illuminated by light coming from an angle. But it’s also possible to display the elevations as different colors for use as a background image for maps, or for shading.

Continue reading ‘Elevation And Contour Line Display In MicroDEM – Make Your Own Simple Topo Maps’