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Archive for May, 2009

Convert TIGER Census Shapefiles (And General Shapefiles As Well) Into Thematic Google Earth KML Files

Published by
Leszek Pawlowicz
 in Google Earth, KML and shapefile. Closed

Bruce Ralston of the University of Tennessee has previously released several US Census TIGER data tools that I’ve posted about in the past. TGR2SHP converts TIGER files into shapefile format, while TGR2KML converts TIGER polygon files (like legislative districts and county subdivisions) into basic KML files for viewing in Google Earth. Both of these tools only work with the older pre-2007 TIGER format, which is no longer in use; the Census Bureau now issues all this TIGER data in standard shapefile format. But Bruce Ralston has just released a new tool called AFF Mapper that goes a step beyond his previous ones: it can convert TIGER shapefile data into KML format, link it to tabular American Fact Finder data (AFF) from the US Census, and plot this census data thematically. But unlike the previous TIGER tools, this one is a general-purpose one; it can convert any shapefile – point, line or polygon – into a thematic or unique value KML file, with the option of using thematic data from a linked external table. The only limitation is that the shapefile must be in geographic coordinates (lat/long), WGS84 datum, Google Earth’s native coordinate system.

I won’t go through the process with Census data; there’s an excellent PDF manual that describes the process of creating maps like this one (from the manual):

Continue reading ‘Convert TIGER Census Shapefiles (And General Shapefiles As Well) Into Thematic Google Earth KML Files’




New Free Stand-Alone MRSID Imagery Viewer/Exporter From LizardTech

Published by
Leszek Pawlowicz
 in GIS. 3 Comments

A long time ago, LizardTech had a stand-alone viewer for MRSID imagery that let you export subsets of the image as TIFF files -  GeoTiffs if the original image was georeferenced. For some reason, that viewer was withdrawn as a free download in favor of a browser plugin, though you could still find the viewer available at some sites. I never really cared for the browser plugin, and kept my copy of their old viewer software safely stashed away.

LizardTech has just released GeoViewer 3.0, a new stand-alone viewer for georeferenced imagery, and a replacement for their $299 GeoView Express product. Note: The initial download is only 670KB, but that’s not the full program; it’s a front-end that downloads the 21 MB installer from LizardTech, so you’ll need a working Internet connection to install the software. It can read:

  • MRSID
  • JPEG 2000
  • GeoTiff
  • ERDAS Imagine
  • ECW
  • Express Server Layers
  • WMS Layers
  • JPIP Layers

… and a bunch more, including vector shapefiles. It also opens JPEG and BMP imagery, and unregistered TIF images, but since it doesn’t seem to be able to use associated UTM worldfiles to register those images, it’s not clear how useful that is. If coordinate system data is embedded in the imagery, it uses the first file to set the native coordinate system, and re-projects successive files to match that native system. If that first file imagery is not in geographic coordinates (lat/long) and WGS84 datum, you’ll also have the option of re-projecting it immediately to lat/long, WGS84:

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You can export either all the loaded data, or just the data in view, as a GeoTiff (Tools => Export), a raster PNG with worldfile, or JPEG with worldfile, in your choice of resolutions, using the Tools => Export menu:

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It also has a path measurement function, which works but is nothing to write home about:

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You can load in multiple layers and mosaic them, and set layer transparencies, but you’re probably better off using other software for that. Really, the big thing about this program is that there’s now an up-t0-date, stand-alone MRSID viewer and imagery exporter from the company that created the format, LizardTech.

Via GISUser.




Online Photo Geotagging With GeoImgr

Published by
Leszek Pawlowicz
 in geotagging. Closed

I’ve covered a fair number of stand-alone geotagging apps before; check the geotagging category on this blog for some examples. But if you don’t have a geotagging application on the computer you’re using, GeoImgr is a web-based app that can geotag photos with a simple Google-Maps-based interface. First, upload a single picture (no batch uploading, unfortunately). GeoImgr lets you upload the image at its full original resolution, so this can take a few seconds. Once uploaded,  a thumbnail of the uploaded photo will appear at upper right:

geoimgr1

Then position the marker in the Google Maps interface at the location where the photo was taken.  Click and drag to move the map, zoom in by clicking the plus button or double-clicking on the map, and position the marker with a single click:

geoimgr2

The position of the marker will be continuously updated at right; click on “tag photo!”, and those marker coordinates will be embedded in the photo’s header. When you click “download photo!”, the geotagged photo will be downloaded with its original filename intact, and the image data unmodified.

Not a substitute for a good stand-alone app, but does the job, easy to use, and always available online.

HT to Michael Kempf (creator of the site).




Simple Google Earth Image Enhancement With SpaceEye

Published by
Leszek Pawlowicz
 in Google Earth. Closed

SpaceEye (direct download link)  runs simultaneously with Google Earth, and lets you perform simple image processing functions on the imagery visible in the Google Earth window. After installing and running the program, it first starts up Google Earth in a partial screen window, then starts itself up either side by side with Google Earth, or overlapping it as in this case:

Continue reading ‘Simple Google Earth Image Enhancement With SpaceEye’




Thematic Mapping Engine API For Displaying Your Own Data In Google Earth

Published by
Leszek Pawlowicz
 in Google Earth. 2 Comments

Almost a year ago, I posted on Bjorn Sandvik’s Thematic Mapping Engine, which can plot data thematically in Google Earth as:

  • Choropleth
  • Prism
  • Proportional symbol
  • Pie chart

At the time, you could only use a limited number of pre-packaged datasets. Bjorn has just announced the Thematic Mapping Engine API, a Javascript library that lets you do thematic mapping in the Google Earth plugin with your own data (including online sources like Google Docs Spreadsheet). Still in beta, and Bjorn is looking for people to try it out (non-commercial use only). Documentation is a bit sparse right now, but if you look at the page source for example maps created with the API, it’s not too hard to figure out.




Free Tools For ArcGIS Server (And A Request For Ideas For More Free Tools)

Published by
Leszek Pawlowicz
 in ESRI and GIS. 1 Comment

David Enns of MapItOut writes:

Subsequent to the development of low-cost tools by Map It Out in previous versions of ArcGIS Server, the company will now release these tools free of cost, starting with ArcGIS Server 9.3. It will be seeking input from users to develop other no cost tools. Map It Out Inc. hopes to offer several other ease-of-use and multi-functional tools at no cost in the upcoming months based on the input/demand from the GIS community.

The first available tools are:

  • Area & Buffer Selection Tool
  • Bookmark Tool
  • Hyperlink Tool
  • Export Tool
  • Custom Query Tool

I don’t use ArcGIS Server, so can’t evaluate them; for anyone who does try them out, I’d welcome your opinions in the comments section.




Make Your Own Map Projection With Flex Projector

Published by
Leszek Pawlowicz
 in cartography. Closed

While most maps, paper or computer, are flat, the world isn’t. Map projections are mathematical methods for representing part or all of the quasi-spherical Earth (irregular oblate spheroid, to be more precise) on a flat surface. The book Flattening the Earth: Two Thousand Years of Map Projections, covers the history and many of the hundreds of projections devised to “flatten the earth”. And I’ve covered a few map projection viewers on this blog before.

Just as a map projection viewer alone, Flex Projector (Java; versions for Windows, Linux and Mac) would be worth a look. It has over 25 pre-defined map projections that you display (along with listed values for their areal/scale/angular errors), and includes the ability to display two projections at once for comparison purposes (here, Plate Carree in black vs. Mercator in gray):

Continue reading ‘Make Your Own Map Projection With Flex Projector’




Easy Google Maps Route Creation With NetKvik

Published by
Leszek Pawlowicz
 in Google Maps and KML. 3 Comments

NetKvik offer an alternate interface to Google Maps for creating routes from one location to another, with easier access to some of Google Maps’ standard options, plus a few added features.

netkvik

Probably the most confusing feature of NetKvik is the zoom function, or the apparent lack of one at first inspection; there’s no standard Google Maps zoom slider. But you can use the +1 and –1 buttons at upper left to zoom in and out, and use the level buttons to jump to gross zoom levels like city, region, or continent; the mouse wheel also  zooms the map in and out. Once you get past that quirk, NetKvik offers a lot.

Like Google Maps, you can drag and drop the destinations and track to modify the route; you also have the option to bypass highways (using the Function menu to select that option. You can also create a link to the map with the route drawn. But unlike Google Maps:

- You can add successive destinations not only by entering the location in a search box, but also by clicking on the map

- Click on Show Data to get coordinates and elevations for your destinations:

nkdetails

- Click on Bicycles to enter details like travel speed and wind direction to get travel time and headwind/tailwind details for a bike trip:

nkbicycle

- Use Details to toggle on/off driving directions; total travel distance is always shown. Print prints out driving directions.

- Option for Point to point routes (great circle routes plotted between destinations)

- A coordinate function option displays latitude/longitude next to the cursor:

5-10-2009-9.40.21 PM

- Export a KML file for your trip in one of three formats:

nkexport

- Weather brings up a weather map from Weather Underground for the location you’re viewing.

- Moving the mouse over every button/feature pops up a concise but useful help screen; when those pop-ups get to be too annoying, you can turn them off.

HT to Carl DK.




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