NOAA’s Meteorological Development Laboratory offers degrib, a multi-platform application that downloads many different kinds of US Weather Service forecast data (e.g. temperature, precipitation, wind, etc.) from the National Digital Forecast Database. Data is available for every 3 hours for the next 72 hours, every 6 hours for the next 7 days. Degrib also converts the data into GIS formats: shapefile, CSV, NetCDF and binary float (.flt) format. Data is also available via WFS, XML, and in a graphic web browser format.
Via The Earth Is Square, which has screenshots and more
PDMarker is “a Javascript library that extends the Google Maps API, making it easier to customize marker behaviour”. Examples and a demo are included.
Via Mapperz.
Although you view a DEM (digital elevation model) as a two-dimensional representation of terrain in MicroDEM, the program can treat it as a 3-dimensional surface and analyze it as such. Perhaps the simplest example of this is in answering the question, “What terrain can you see when you’re standing at a specific location?”, and MicroDEM has tools that let you do that.
Continue reading ‘"I Can See My House From Here": Line-Of-Sight And Viewsheds In MicroDEM’
Another set of free utilities for ESRI products, a complementary set to the ones from this previous post. This time they’re mainly for older versions of ArcView (but there’s a couple of more recent ArcGIS tools as well). Available here.
A useful collection of links to map symbols is the Unofficial Arc/Info & ArcView Symbol Page. While some of the links are strictly for ArcView palettes and ArcInfo line and marker sets, a fair number link to graphic symbols and TrueType Fonts useable in any compatible GIS or mapmaking software. Symbol sets cover a wide variety, including roads and highways, geology, and animals. Most, but not all, are free. Also check out the links at the bottom of the page to free clip art resources.
A screen capture utility is a useful program to have for capturing map images off of web pages, or map displays in programs that don’t offer the capability to save the display as a graphic image. There are lots of them around, but I like mine to be simple, fast, and unobtrusive. My favorite is HoverSnap:
There’s no installation program, just unzip and run it. Clicking on the “Hide” button at the bottom minimizes it to the system tray; clicking once on the icon brings the options window above back. At the bottom, enter the default folder where you want the screen captures to be saved, and a filename to save them under. I recommend checking the “Auto-generate filename …” option, as this will append the date and time to the filename; otherwise, every successive capture will overwrite the previous one. You can save in JPEG, PNG, BMP or GIF formats, and either save at the current resolution or resize the captures to a specific pixel dimension.
When the program is running, pressing the “Print Screen” key saves the entire screen, Alt-Print-Screen saves the active window, and Ctrl-Print-Screen turns the mouse cursor into a crosshair that you can use to select a custom rectangle on the screen for saving by clicking and dragging. As a bonus, the download page for HoverSnap also includes free downloads of some other useful utilities, including a registry cleaner and an IP utility.
For a program with a few more options (more graphic file formats, ability to capture the mouse cursor image, custom capture keys), you might try Gadwin PrintScreen.
If you need to identify a township or section on map, or plot Public Land Survey Systems (PLSS) boundaries, you can get this data from the Land Survey Information System website, managed by the BLM. Shapefile data is available for most of the US, grouped by state and/or county, in the NAD83 datum. File data includes township, section, subsection, latitude/longitude, and metadata. Note: Make sure you have pop-ups enabled.
There’s also a Township Geocoder web form. Enter the latitude and longitude of the point you’re interested in, NAD27 or NAD83, and get back the state, principal meridian, township, range, section, quarter section, and quarter-quarter section. Or enter the previous data, and get back a latitude/longitude. You can enter individual points, or upload a file for batch point conversion.
Yesterday’s post dealt with the basics of installing MicroDEM, and opening up DEM terrain files in the program. Now it’s time to look at different ways to display terrain reflectance in DEM. While 3DEM is better for some kinds of displays, MicroDEM has more different ways to display reflectance.
Continue reading ‘Modifying The Terrain Reflectance Display In MicroDEM’
