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Archive for September, 2009

High-Resolution Terrestrial Biome Data

Published by
Leszek Pawlowicz
 in data and global warming. Closed

The USGS Global Ecosystems Viewer (background info here) lets you view terrestrial biome data in very fine detail, with extensive categorization levels. Coverage is currently limited to the US, but the background page indicates that the rest of North America, South America and Africa are currently being worked on. Click on the map, and get a popup detailing vegetation classification, lithology, moisture, terrain, and other data:

biomepopup

For this example, the Ecosystems data is:

Ecosystem:
Southern Rocky Mountain Ponderosa Pine Savanna (580)

Topo Moisture Potential:
Dry Uplands (3)

Land Surface Form:
Hills (6)

Surficial Lithology:
Non-Carbonate Residual Material (3)

Isobioclimate:
Upper Supramediterranean Dry (51)

and the Topographic data:

Elevation:
2248 meters

7375 feet

Slope:
8°

Aspect:
102° (E)

You can also do a colored plot of any of the ecosystems parameters by themselves, like this one of the Surficial Lithology:

surfaceforms

With a button to bring up the legend in a pop-up window:

formslegend

Background imagery can be satellite photos (as in the example above) with and without borders and placenames, topographic maps (USGS 100K), or no background at all. Finally, you can order data for your current view for download in georeferenced format (UTM, Albers or geographic projection) in ArcGrid, GeoTiff or ERDAS IMAGINE formats. Data will be prepared and available for download via FTP; you get email notice of this, but there’s also a status update page you can use. When I tried it, the data was ready for download in less than five minutes.

Via Spatial Sustain.




Simplified Scree Shading For Maps

Published by
Leszek Pawlowicz
 in cartography. 1 Comment

While good shaded relief is still a cartographic art (see the Shaded Relief and Relief Shading websites for more info), programs like 3DEM, MicroDEM and others can create decent shaded relief effects using digital elevation models (DEM) to shade raster graphic files. Here’s a sample USGS topo map shaded using 3DEM:

toporeliefshaded

Another style of relief shading is scree shading, also called Swiss-style; it involves drawing small dots representing rocks on maps to provide texturing. In the past, there’s been no way to automate this process, so the only way to do it was by hand, a slow and time-consuming process. Bernhard Jenny of the Swiss ETH has recently introduced Scree Painter, a Java program (Windows, Mac and Linux) that, while not exactly fully automating the process or making it simple, at least makes it far more practical. Mandatory data required includes:

  • A mask to define the size of stones (raster grayscale image with worldfile); darker areas will have larger stones
  • A DEM (ESRI ASCII Grid format) to define gullies
  • Shapefile polygons to define where scree stones will be placed
  • A raster obstacle mask (with worldfile) where black defines areas where no stones will be placed; sometimes this can be the main raster map image

Optional data includes gully lines, a background reference image, and gradation and large stones masks. Once the data is loaded in, sliders let you vary parameters that change the density, shading and shadowing of stones. You can download a sample dataset to play with from the website. Here’s the original map:

original

Using a shaded relief program, I could convert this into:

reliefshaded

But by loading it into Scree Painter, and randomly selecting some  parameters, I can get this:

screepainter

Not every good, but then I didn’t try very hard. The sample data includes a reference image that shows what the program is capable of:

reference

Unfortunately, it doesn’t appear as though you can export the full original map with generated scree and gullies directly. You can export the scree and gully data in a variety of vector and raster format, but you then have to re-combine this data with the original map using a GIS or graphics program to get a result that looks like the one above. Hopefully the author will add the option to export the full image in a georeferenced format in the future.

Via Kelso’s Corner.




Free Sampling Design Tool Extension For ArcGIS

Published by
Leszek Pawlowicz
 in ESRI and GIS. Closed

The Sampling Design Tool is another free ArcGIS extension from NOAA’s Center for Coastal Monitoring and Assessment, the source of the Habitat Digitizer Extension I posted about last week.  Key features (from the PDF manual):

  • Spatial sampling –sampling and incorporation of inherently spatial layers (e.g.
    benthic habitat maps, administrative boundaries), and evaluation of spatial
    issues (e.g. protected area effectiveness)
  • Scalable data requirements – data requirements for sample selection can be
    as simple as a polygon defining the area to be surveyed to using existing
    sample data and a stratified sample frame for optimally allocating samples
  • Random selection -eliminates sampling biases and corresponding criticisms
    encountered when samples are selected non-randomly
  • Multiple sampling designs – simple, stratified, and two-stage sampling
    designs
  • Sample unit-based sampling – points or polygons are selected from a sample
    frame
  • Area-based sampling – random points are generated within a polygon
  • Analysis – previously collected data can be used to compute sample size
    requirements or efficiently allocate samples among strata
  • Computations –mean, standard error, confidence intervals for sample data
    and inferences of population parameters with known certainty
  • Output – geographic positions in output simplifies migration to global
    positioning systems, and sample size estimates and sample statistics can be
    exported to text files for record keeping

Example of random sampling (from the manual):

randomsampling




Free Vector Country Borders, Administrative Boundaries, And Soon More

Published by
Leszek Pawlowicz
 in data, GIS and shapefile. 4 Comments

Wish I’d known about this site when I was hunting for a high-res border outline for the province of Umbria in Italy. The Global Administrative Boundaries website offers free vector GIS data for country borders and administrative areas within those borders. Data is available in geographic coordinates (lat/long), WGS84 datum, in multiple formats:

Coverage is worldwide for level 1 data (country borders), but diminishes as you go down as far as level 4 (sub-administrative units), though for the latter there are some countries for which such a data level isn’t relevant. You can see maps of current level coverage here, and missing data will likely be added in the future. Data is licensed under Creative Commons for the US; other unspecified terms may apply for the rest of the world. Here’s the Italian province of Umbria, with the best free data I could initially find plotted in purple, and the high-res GADM data in blue:

umbria

Via Slashgeo.

Just around the corner, scheduled for unveiling at the October 2009 NACIS conference, is Natural Earth Vector. While there’s some overlap with GADM at the upper boundary levels, Natural Earth Vector may not include some of the finer administrative boundaries available in the GADM . But it will have a wide variety of other geographic features not available in GADM in vector format at multiple zoom levels (list from the web post):

  • Continents (North America, Europe, Asia, etc)
  • Cultural regions (South Asia, West Africa, etc)
  • Countries (US, Canada, Mexico, etc)
  • Country sub-divisions (for the US, states, semi-independent territories, dependencies, associations)
  • Disputed territories (like Kashmir, Northern Cyprus)
  • 1st order admins (states, provs)
  • Bathymetry
  • Lakes
  • Lake Center Lines
  • Rivers (including attributes that allow easy “tapering” of drains)
  • Islands
  • Glaciers
  • Populated places (urban boundaries, not city points)
  • Cities (point locations)
  • Physical features like peaks, ranges, valleys, plains

I’ll try to post again when it’s officially released.

Via Kelso’s Corner.




Portable GIS 2.0 Released

Published by
Leszek Pawlowicz
 in GIS. Closed

A little more than a year ago, I posted about the release of Portable GIS 1.0, aka “GIS on a stick”, a suite of portable GIS programs that could be installed on a thumb drive and run from any computer. Jo Cook of Oxford Archaeology has just released version 2.0, which offers more features, including updated versions of software available on version 1.0:

  • gvSIG (1.1.2)
  • Quantum GIS (1.02)
  • Grass (accessed through Quantum GIS)
  • PostgreSQL (8.4.01)
  • PostGIS (1.4.0)
  • Xampplite: PHP, MySQL, Apache (1.6.2)
  • Geoserver (1.7.6)
  • FWTools: ogr, gdal, python, mapserver, openEV (2.4.2)

Plus a bunch of new apps for 2.0:

  • Tilecache (2.10)
  • Featureserver (1.12)
  • PgAdmin III (1.10)
  • OpenLayers (2.8)
  • uDig (1.1.1)
  • SqlSync (cross-platform database synchronization)
  • Shp2Text (converts shapefiles into csv, with coordinate columns)
  • Ogr2Gui (GUI for OGR toolkit)
  • ShapeChecker (Checks and fixes corrupt shape files)
  • GeoMetadataExtractor (extracts metadata from georeferenced images)
  • libgeoGUI (extracts and embeds worldfiles and metadata to/from GeoTiffs)

Was surprised to see the last two, as they’re a couple of my own modest utilities:

Program comes with a self-contained installer that lets you select the drive you want to install the package on. This would normally be a thumb drive, but you could also install it on your own root drive or an external hard drive if you like for a quick and easy set of hard-drive-based GIS apps. If installed on a hard drive, I’d recommend deleting the autorun.inf file, as that will change the drive icon to that of the PortableGIS control panel app. You’ll find the latter in the root directory of the drive you installed it on:

PortableGISCP

I found configuring the original system variables a bit of a pain with version 1.0, and simply couldn’t get some apps to work correctly; version 2.0 makes it a lot easier by just clicking the Setup Portable GIS button above and following the directions in the command window that pops up. You have to do this every time you run Portable GIS with a different drive letter, which means only once if you install it on a hard drive. The other tabs let you select the desktop apps to run:

PGModules

And start and stop server apps required by some of the desktop apps:

PGWeb

As installed, the Portable GIS suite takes up about 1.2 GB of space, which means it won’t fit on a 1 GB thumb drive by itself as version 1.0 would with a bit of extra effort; but two GB thumb drives are pretty cheap these days.

A final tip: as installed, the Portable GIS menu will come up automatically whenever you plug the thumb drive into a computer that has AutoPlay enabled. If you don’t want this (like me), just delete the autorun.inf file on the thumb drive.

Portable GIS 2.0 is free, and freely distributable; however, if you want a custom enterprise-ready version of this suite, OA Digital offers this as a paid service.




Plot KML And KMZ Points And Paths In A Stand-Alone Google Maps Viewer

Published by
Leszek Pawlowicz
 in Google Maps and KML. Closed

The stand-alone GPS Map Viewer plots points and paths from a KML or KMZ file in a Google Maps view. While you can do this with any number of online apps, including the My Maps feature in Google Maps itself, the GPS Map Viewer offers a couple extra functions not available in some of those.

gpsmapview

  • Get a list of all the individual points in a KML path in the info pane at left. Clicking on any of them, or on a individual waypoint, will bring up their position info in the bottom left pane, where you can copy and paste it somewhere else.
  • Move the cursor over any point plotted at right, and its name will show as a pop-up
  • Double-click on any path point to highlight it in red, and re-center the map on it; same effect by dragging and dropping a point from the list onto the map.
  • Clicking on the small vertical red line brings up a toolbar

gpsmapviewtoolbar

Functions from left to right are to save the view as a JPG, Print Setup, Print Preview, and print the map view with plotted data directly. You can drag and drop this toolbar anywhere it’s convenient.

Here’s a YouTube video demonstrating the program:




EarthCache: Geology-Oriented Geocaching

Published by
Leszek Pawlowicz
 in geology and GPS. Closed

I’ve never really gotten interested in “geocaching”, the recreational sport of tracking down of hidden containers or cache by geographic location. But I’ve just found out about a related variant that meshes nicely with my interest in geology: EarthCache. As with a geocache, you go to a location based on geographical coordinates, but the reward is not tracking down a box or trinket, but seeing an area with interesting or unique geological features. Earthcaches are located around the world, with roughly half of them are in the United States. There’s a searchable index that lets you locate Earthcaches by country, state, and type (fossil site, erosional feature, igneous feature, etc.). Quick tip: for sites in America, choose “USA” for the country rather than “United States”’; the latter only has a few sites listed. Once you locate a site of interest, clicking on the link will take you to the information page for the site at Geocaching.com:

EarthCache

The information page generally includes a description of what makes the site interesting geologically, often with diagrams, photos and references. For full site coordinate data, you’ll need to register at the site and agree to a standard disclaimer, i.e. they’re not responsible for anything bad that might happen. Once registered, the coordinates will show up at the top, along with the option to download a LOC waypoint file. GPX file downloads require a paid membership, but LOC files can be opened using the free program EasyGPS and then either directly uploaded to your GPS or saved as a GPX file.

If you want to keep track of the sites you’ve visited, and get official recording of your visit at the Geocaching site, the info page will list off some required information, like photos, a general description, and several questions to answer about the geology. You can also leave comments about your visit, or read those of others before you go. And if you have a site that you think would make a good EarthCache, you can submit it. This is a great resource for both geology nuts and educators.




Habitat Digitizer Extension For ArcGIS

Published by
Leszek Pawlowicz
 in ESRI, GIS and shapefile. Closed

Stumbled across this the other day, and while I don’t currently have the need for it (or a copy of ArcGIS to try it out on), it sounds useful enough to post about. NOAA’s Center for Coastal Monitoring and Assessment offers a free extension for ArcGIS called the Habitat Digitizer:

The Habitat Digitizer Extension is designed to use a hierarchical classification scheme to delineate habitats by visually interpreting georeferenced images such as aerial photographs, satellite images, and side scan sonar. The extension allows users to create custom classification schemes and rapidly delineate and attribute polygons, lines, and points using simple menus. The extension allows new hierarchical classification schemes to be easily created, modified, and saved for use on future mapping projects. There are several advantages to using classification schemes with a hierarchical structure including: the detail of habitat categories can be expanded or collapsed to suit user needs, the thematic accuracy of each category/hierarchical level can be determined, and additional categories can be easily added or deleted at any level of the scheme to suit user needs.

Habitat_Digitizer

While written for habitat digitization, it could prove useful for any digitization projects with extensive classification requirements. Versions are available for ArcView 3.0, ArcGIS 9.0, and ArcGIS 9.2 from the product page; download files include a PDF manual.




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