I’ve posted about MapWindow in earlier posts on Shape2Earth (a shapefile to KML converter), and on reprojecting shapefiles from one coordinate system to another. So I figured it was time to take a longer look at some of MapWindow’s GIS capabilities, since it’s one of the best open source shapefile viewers and editors out there, and has many other useful functions. In addition, GIS novices might find this series useful as a general introduction to GIS programs, since it covers some of the basic operations applicable to other GIS programs as well.
Continue reading ‘Introduction To MapWindow GIS I – Shapefile Viewing’
I love rocks. I love dirt. And I love the maps that show them. A good geology map is visually like a weird hybrid between a Peter Max poster and Jackson Pollock drip painting, but also tells a story spanning several billion years of Earth’s history. I’ve found a few websites where you can find and download geology maps in a variety of formats.
Continue reading ‘Rocks And Dirt – Geology And Soil Maps Of The US And World’
Here’s a short post recapping my series on free (or cheap) ways to export shapefiles to Google Earth’s KML format:
Using GPS TrackMaker to quickly export point and line shapefiles into KML format. Not a lot of flexibility, though, and limited attribute export.
Shp2KML exports point, line and polygon shapefiles, with more attribute data than GPS TrackMaker. No ability to modify KML plots based on attribute data, limiting usefulness, especially for polygons.
shp2kml uses a wizard approach to export shapefile data to KML format. Allows you to export multiple attributes, and to vary plot color depending on attribute value. Has some problems with large shapefiles.
The only paid solution here ($29.99), but by far the most flexible and powerful.
Since the first two solutions above require the shapefile to be in Google Earth’s native coordinate system (geographic coordinates, WGS84 datum), here’s a great program to convert shapefiles in virtually any coordinate system to the right one for Google Earth.
The U.S. Census Bureau produces TIGER/Line vector data files (Topologically Integrated Geographic Encoding and Referencing). From the Census Bureau’s TIGER overview:
“The TIGER/Line files are a digital database of geographic features, such as roads, railroads, rivers, lakes, legal boundaries, census statistical boundaries, etc. covering the entire United States. The data base contains information about these features such as their location in latitude and longitude, the name, the type of feature, address ranges for most streets, the geographic relationship to other features, and other related information.”
These TIGER files are updated yearly, and contain some of the most current digital data for US streets and addresses. Most GIS programs can’t open TIGER vector files, and ESRI only has free TIGER data in shapefile format for the year 2000. Now a TIGER-to-shapefile converter that used to be a paid commercial program has been released as open source software, free for any use, along with a number of other useful TIGER and Census demographic data utilities.
Continue reading ‘Converting US Census TIGER Data Into Shapefiles For Free’
The Mapperz blog has a new post on ArcGIS 9.2’s Simplify Polygon feature:
“Simplifies a polygon by removing small fluctuations or extraneous bends from its boundary while preserving its essential shape.”
A nice tool to have to simplify polygon shapefiles with too high a level of detail. But suppose you don’t have ArcGIS 9.2 (at around $1500 list)? There’s a free web-based shapefile utility that does something similar.
Continue reading ‘Simplifying Line And Polygon Shapefiles’
Shapefiles can be created in any coordinate system, and are often (and annoyingly) found in a coordinate system different than the one you’d like them to be in. For example, several of the shapefile to KML converters posted about recently require that the shapefile be in Google Earth’s native coordinate system: geographic coordinates (latitude/longitude), WGS84 datum; what do you do if your shapefile is in a different coordinate system, like UTM, Lambert Conformal Conic, or State Plane Coordinate System? There are lots of free conversion utilities out there that can reproject shapefiles from one coordinate system/datum to another, but there’s one I prefer because it’s fast and easy to use.
Continue reading ‘A Free And Easy Shapefile Coordinate Converter’
The three previous posts in this series have examined completely free options for exporting shapefile data into Google Earth’s KML format. Each of those had advantages and disadvantages, with the biggest advantage for all being that they’re completely free.Today I’ll take a look at an option that isn’t free, but which at $29.99 I would classify as “cheap”, especially given its capabilities. And the free demo version lets you import up to 1000 features, enough to evaluate whether it meets your needs.
Continue reading ‘Exporting Shapefiles To Google Earth IV – Shape2Earth’
Note: shp2kml seems to be currently unavailable; try AFFMapper as an alternative.
Two earlier posts talked about free, quick and simple ways to export shapefile data to Google Earth’s KML format. Both had limitations on how much of the shapefile’s attribute data could be imported into the KML file, and how the shapefile data could be displayed, especially polygon shapefiles. There are two programs I know of that allow you to export shapefile data to KML format with multiple attributes, and also modify the colors with which the shapefile data is plotted based on attribute data. One program is completely free, but has quirks and limitations; the other is not free but cheap, and is more flexible and capable. Today’s post looks at the free one.
Continue reading ‘Exporting Shapefiles To Google Earth III – shp2kml’
