blankblank blank


Archive for the 'GIS' Category Page 4 of 20



Free Sampling Design Tool Extension For ArcGIS

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

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

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.




Habitat Digitizer Extension For ArcGIS

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.




GUI For Generic Mapping Tools (GMT) Plus Added Geophysics Tools

The Generic Mapping Tools (GMT) is a collection of 60-odd command line tools for manipulating gridded and vector data, and creating high-quality output in EPS (Encapsulated PostScript) format. Working with it in command-line format isn’t the most user-friendly experience. Mirone offers a far-more accessible GUI interface to GMT’s features, and adds a few geophysics-related capabilities of its own:

  • Multibeam mission planning
  • Elastic deformation studies
  • Tsunami propagation modeling
  • Earth magnetic field computations and magnetic Parker inversions
  • Euler rotations and poles computations
  • Plate tectonic reconstructions
  • Seismicity and focal mechanism plotting

If you have MatLab installed on your system, there are source code versions available for Windows, Mac and Linux. If not, there’s a stand-alone executable for Windows systems that runs slower than the MatLab version.

Other graphical front-ends for parts of GMT include iGMT (requires Tcl/Tck), Win4GMT, and SeaTree.




FalconView Released As Open Source

FalconView is the Windows mapping part of the Air Force’s Portable Flight Planning Software (PFPS), under development by Georgia Tech since 1994; see this link for an interesting history of the politics of software development in the military. This mapping part, stripped of all mission planning components, has recently been OK’ed by the Air Force for release by as Open Source software. The program has an strong list of features, including:

  • Support for many raster/vector map formats
    • GeoTIFF
    • TIROS TopoBath
    • Digital Terrain Elevation Data (DTED) / LIDAR
    • Vector Product Format (VPF)
    • CADRG
    • MrSID
    • GeoPDF
    • WMS
    • ArcMap .mxd (requires that ArcGIS be installed)
    • Shapefiles
    • KML/KMZ (including network links)
  • Moving map supported if you have a connected GPS
  • Generate and overlay contour lines from elevation data
  • Skyview mode lets you fly through terrain with overlays by keyboard/joystick control

skyview

But this open source version is labeled as alpha software, and it definitely is:

  • It wouldn’t install successfully on two separate Vista systems, claiming problems with MapServer initialization; was finally able to get it installed on a Windows XP system
  • It’s a huge download (about 500 MB), partially because it also contains critical supporting applications like DotNetFX and Windows SQL Server that must be installed in order to run the program
  • Some operations can run slowly on older systems
  • Occasional crashes on my system

A bigger problem is that it’s a complicated program with lots of features and a non-intuitive interface. Documentation is currently limited to the help file, which is clearly intended for someone who’s already familiar with the program; no manuals or other documentation is currently available. I struggled for several hours trying to figure out  the simplest task possible, add a raster image to the map and view it, before finally giving up. I may not be the sharpest tool in the shed, but I’m not the dullest, either.

FalconView also installs GeoRect, a program to georectify imagery and export it in GeoTiff format. I had hopes that this could be used to convert GeoPDF files into GeoTiff format, since it does open GeoPDF files. But I was defeated on this score as well; while the help file is substantially more helpful than that for FalconView, I was unsuccessful even following their step-by-step instructions. And it appeared as though it would only convert a beta USGS quad in GeoPDF format to a GeoTiff far smaller than would be necessary for full resolution.

I welcome comments from anyone who’s used this program before, and can offer pointers, and I’ll keep an eye on it for the future. But until there’s substantially better documentation available, I’m not going to spend a lot of time struggling my way through this software.

HT to Thomas Larsen.




Map Maker Gratis: Free Map Editor

Map Maker Gratis is the free version of the professional $400 GIS and map editor Map Maker Pro. I’ve been meaning to try it out for a while, since even the free version has a very strong feature set. From the website:

  • Unlimited number of layers, raster and vector.
  • Colour, mono, and grey-scale bitmap backgrounds.
  • Large range of fill, line, and symbol styles
  • Translucent and semi-translucent fills.
  • Curved, stretched, and outline text.
  • Arrows, and dimensions.
  • Easy to create scale bars, north points, legends, text panels, inset images, etc.
  • Point-and-click to pop-up images, documents and internet links.
  • Print accurately scaled maps on any true Windows compatible printer.
  • Multi-sheet printing of large maps.
  • Create from new or import and edit.
  • Vector drawing and editing.
  • Intuitive cutting and joining of polygons.
  • Create polygons with islands.
  • Simple editing of common boundaries.
  • Numerous “snap-to” options.
  • Drag, stretch, rotate, duplicate groups of objects.
  • Create buffer zones.
  • Calibrate raster images.
  • Use data from DBF files to colour up a map or determine symbols.
  • Generate legends.
  • Measuring areas and lengths is simple.
  • Edit data sets.
  • Import vector data including ArcView SHP, MapInfo MIF, AutoCAD DXF, Idrisi VXP.
  • View BMP, TIF, Geo-Tiff,  and JPG raster data.
  • Export BMP, JPG, TIF.
  • Export DBF data to Microsoft Access, Excel, dBase etc.

The Pro version adds support for 3D, raster-to-vector, on-the-fly reprojection, export of vector features from the native .dra format to standard formats (shapefile, MapInfo, etc.),  and more; see the comparison chart for all the differences. And the install program lets you try out the Pro version for 30 days before it reverts to the free Gratis version. So it seemed worth a look on a simple map project I was doing for a friend as a favor.

Having struggled with the program for a few days, I can see that it does have many features; unfortunately, it also has a fairly steep learning curve, especially for those used to more conventional GIS programs. For example, modifying vector file display attributes isn’t done by modifying the layer properties, but rather by defining a “style”, a set of descriptions for things like symbol, line width, fill patterns and more, and figuring out how to do that effectively takes some work (and sometimes doesn’t work the way you expect). Getting labels to appear in the position I wanted was a chore, and some of the label controls didn’t seem to work. You can have multiple layers of vector data loaded, but it seems that you can only work with data in a single, “active” layer, i.e. you can’t edit or add points to layers other than the active layer.  There’s a large PDF manual that comes with the program, and at first glance it seemed to be comprehensive. But when I ran into problems and looked in the manual for answers, more often than not I couldn’t find them.

I suspect that if I worked long enough with the program, I would eventually figure out what it can and can’t do. There are some limited tutorials available for download at the site, along with links to tutorials by other users. Given the feature set, and the price point of $0 for the Gratis version, I can’t complain too much, and can see myself revisiting the program at some point in the future to give it a more complete review.

I should mention that the program authors generously offer free licenses for the Pro version to any non-profit organization, educational institution, or students in Africa. Also, there’s a world clock / sunlit area display program called Sun Clock available for a 30-day full-featured demo; at the end of 30 days, some features disappear (like views of the sky and stars), but the world clock /sunlit areas feature remains free.

SunClock




Disaster Response Map Symbols

The Portuguese chapter of the Association Of Volunteer Emergency Response Teams, in collaboration with Peter Guth and Donald Springer, is working to create a general-purpose set of symbols useful in mapping the position and condition of infrastructure, resources and incidents during emergency situations. You can download these Disaster Response Map Symbols as a True Type font from the DRMS website, along with a PDF file that documents the symbols There are 253 symbols depicting infrastructure, resources and incidents (graphic from the help file for MicroDEM, Peter Guth’s freeware GIS):

drms table

And additional dot symbols that represent the status of the higher-level symbol:

drmsstatus

These status symbols would be plotted directly below the higher-level symbol, to indicates its condition/status:

commstatus

Any GIS software that can use True Type fonts for symbols or labeling can use the DRMS symbol set directly. But MicroDEM has some special capabilities built in for working with this symbology. Make sure you’ve used the most recent program install, which includes the DRMS True-Type font; also, download the latest executable and copy it into the program directory.

From MicroDEM’s File => Tools menu, selecting Military icon generator brings up the icon composer window; make sure the DRMS tab is selected:

iconcomposer1

Double-click on an icon to select it, and then modify it as you like:

  • Use the color button to modify the color
  • Use Left/Right/Top/Bottom to add text around the symbol.
  • Select the Infrastructure status to plot dots depicting the status of the feature underneath the symbol
  • Modify the test and symbol size using the arrow keys

iconcomposer2

Once the symbol design is complete, you can save the symbol to the clipboard to paste into a graphics program, or choose “Save to file” to save it as a PNG, GIF, JPG, BMP or Targa format graphic file for those GIS programs that let you select graphic images to represent points.

You can also plot these symbols directly on a map in MicroDEM. Open up a georeferenced raster image in MicroDEM:

raster

Clicking on the Map Annotation button on the toolbar (second from the left), choose Military icons from the drop-down, and then enter a filename to save the locations for the icons you want to place. You’ll then use the same Icon Composer interface as above to design your DRMS icons. The Left text is used as a feature ID in the DBF file, and also in the KML file you have the option of creating later on. Once you’ve designed your icon, you can double-click on the raster map to place the icon on that map:

mapwithicons

Click on the “Close” button in the Icon Composer when you’re done. You can now export this map image directly to a generic image file or GeoTiff using the appropriate File => Save … option. But by right-clicking on the map, choosing Load => Google Earth overlay, you can export both the raster image and vector points to Google Earth. Here’s the raster overlay in Google Earth (vector overlay is turned off):

drmsraster

And here are the vector points, with the selected icons, for the same area (raster overlay turned off):

drmsvector

These data files are loaded into Google Earth automatically, but they’re not saved; to keep them for future use, right-click on the dataset listed in the Google Earth Places pane, choose “Save Place As”, then save it as a KMZ file.

Closing the Icon Composer will also open up a DBF  table window with the locations of the points you’ve just created; you can convert that to a point shapefile by clicking on the Report button, then selecting point shapefile. There’s also an option with this Report to create a KML file, but make sure you save this KML file in an empty folder. As I found out by testing it, this option creates a KMZ file, copies every single file in that folder into the KMZ file, then deletes the original file from the folder. If this happens to you, rename the KMZ extension to ZIP, then use your favorite unzipping program to extract out the original files. Also, the KMZ file contains only the KML text data, which  references the graphic icon files in a local directory on your computer for display in Google Earth. If you want to save this file for future use on your computer or another computer, and keep the graphics, you will need to open the file immediately in Google Earth, then save it as a KMZ file (right-click, choose “Save Place As”,etc.).