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Archive for the 'coordinate conversion' Category

Spreadsheet Tools For Lat/Long, MGRS and UTM Coordinate Conversions

Published at June 23, 2008 in coordinate conversion. 0 Comments

Cartisan Maps has several free spreadsheet tools for basic coordinate conversions; each one can handle up to 5000 sets of coordinates. Files are in Microsoft Excel format, but seem to work fine in OpenOffice 2.4.

Cartisan Map Coordinate Converter: Enter latitude and longitude in separate columns for degrees, minutes and seconds, and have them converted to a DD MM SS string, DD MM.d string, or numeric decimal degrees. The first column, labeled Hemisphere, is multiplied times the longitude, and if you leave it blank, the calculated degree value for longitude will always be zero. Enter “1″ for East longitudes, “-1″ for West longitudes, and make sure your longitude degree value is always positive; or, enter a “1″, and then enter positive and negative values for the longitude degree value. Cartisan also has a link to simple VBA code to do these transformations, which you can download.

Cartisan Total Map Coordinate Converter: Converts from decimal and DDMMSS latitude/longitude to UTM and MGRS, and back again; includes support for 14 datums, including NAD27 and WGS84. Also has another version of a converter from degrees/minutes/seconds to decimal degrees and back, similar in output to the one above.Requires that you have macros enabled in your spreadsheet program. Notes: 1. File is in the .RAR compression format; if your unzipping program can’t handle that, try 7-Zip. 2. Enter your coordinate data in the areas highlighted in green in the spreadsheet.



Projection Parameters / Point-Of-Origin For State Plane Coordinate Systems (SPCS)

Published at May 9, 2008 in coordinate conversion. 1 Comment

In a comment on this post, Theron was looking for command-line solutions for converting from UTM to SPCS coordinates on a Unix system; I pointed him towards OGR and GeoTrans as possibilities, and he found that GeoTrans offered a solution. But he also discovered that finding the projection parameters for SPCS wasn’t as easy as he thought it would be. He did track down a few using Google, and was good enough to send them on to me:

A simple, unorganized text listing

Links to both a CSV-listing and an Excel spreadsheet

To find the proper SPCS zone for your location, you can use the program described in the above-linked post, or try this website.



Using The Demo Version Of Global Mapper As A Raster/Vector Data Viewer

Published at May 6, 2008 in GIS and coordinate conversion. 1 Comment

Global Mapper is a first-rate program for viewing and converting GIS data, raster (image and elevation) and vector. It opens over 100 different raster/vector formats, with on-the-fly support/display conversion of virtually every coordinate system / projection / datum you can think of, and some you might not (the Moon, Mars, the moons of Jupiter). It comes in a demo version with the following limitations (from the help file):

  • You will be unable to export data to any format.
  • You will be limited to loading a maximum of 4 data files at a time. With the full version, you can load any number of data files simultaneously.
  • No 3D capabilities (full version supports 3D views, viewsheds, line of sight, cut-and-fill volumen
  • You will be unable to load workspaces.
  • You will be unable to work with map catalogs.
  • You will be unable to download data from WMS map servers.
  • You will be unable to save rectified imagery to fully rectified files.
  • You will not be able to print to a specific scale (i.e. 1:1000).
  • You will have to endure a nagging registration dialog every time that you run the program.
  • You will not be eligible for free email support.

There’s one more, which is you don’t have the option of printing/exporting the screen display as an image file (though you can still print to a printer what’s visible on screen; zoom in to get a higher-resolution printout). Global Mapper’s display options for vector objects are also more limited than a standard GIS data viewer (e.g. no coloring by attribute for shapefiles). For those two reason, the TatukGIS viewer may be a better choice, since it lets you export the data view, raster or vector, as a high-resolution georeferenced raster image. But TatukGIS Viewer only supports about 30-odd raster and vector file formats, and doesn’t do on-the-fly re-projection. For examining the occasional odd data format you run across, in unusual projections/coordinate systems, and making a quick print, Global Mapper is good to have in your toolbox.

As a bonus, it also has a great line/area measurement function, which lets you modify the measurement units from metric to English and back on the fly, and copy them into the clipboard:

gmmeasure

The TatukGIS Viewer has a measure function, but it gives area only in the data’s native projection, less than useful if it’s in the geographic coordinate system (e.g. square degrees for area).

Finally, if you’re looking for an all-purpose data format converter with batch conversion capabilities, don’t need the considerable power (or expense) of FME, and don’t want to deal with the GDAL command-line utilities, you could do far worse than the $299 fully-registered version of Global Mapper.



AZ Garmin Topo Maps And More From The GPS File Depot

Published at April 15, 2008 in GPS, GPX, Garmin, coordinate conversion and topographic maps. 0 Comments

Dan Bloomberg wrote to tell me of his new website, the GPS File Depot. Some useful stuff for GPS users, especially Garmin owners:



Options For MGRS Coordinate Conversion And Viewing

Published at February 26, 2008 in MicroDEM and coordinate conversion. 1 Comment

My visitation logs show a surprisingly large number of visitors interested in converters for the Military Grid Reference System (MGRS), the standard geocoordinate system used by members of the NATO Alliance. So I thought I’d do a quick roundup of previous links/posts related to MGRS, and then talk about another program that might be useful if you’re working in that coordinate system.

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Reproject NOAA BSB Raster Navigation Charts And Export Them In TIFF Format

Published at February 6, 2008 in ESRI, cartography, coordinate conversion, data and topographic maps. 1 Comment

Yesterday, I posted about a NOAA site where you can download Raster Navigation Charts (RNC), maps of coastal and inland waterways. The charts are currently only available in BSB format, which many GIS programs can’t handle; I linked to a few free viewers that will let you view the maps, but not export them. They’re also only available in the Mercator NAD83 projection/datum. Peter Guth (the author of the terrain analysis GIS MicroDEM) let me know about a free utility available from NOAA called the Digital NOAA Nautical Chart Reprojector. It lets you re-project the BSB maps into one of 32 projections (e.g. geographic or UTM) and over 100 datums, then exports the chart in BSB, RAW or TIFF format with a world file; the latter virtually every GIS program and graphics editor can open. It looks like it was originally a command-line utility, since a DOS box pops up when you run the program, but it now comes with a GUI:

NOAA Chart Reprojector

The Input File and Output File dialog windows are a bit clumsy to use until you figure them out, but for the input file, you’re looking for the .kap file that came with the zip file you downloaded from the NOAA mapsite. Choose the desired output parameters at right, including choice of output file format (TIFF here), projection (UTM) and datum (WGS_84). The GUI doesn’t set the UTM zone automatically, but you’ll see the West and East Bounds for the map in the Input Info window at left, and can use those as a guide for setting the correct UTM zone with the Projection Parameters dropdown at right. In this case, clicking “Run” will create the TIF file specified as the output file, along with its worldfile. The file extension for that worldfile will be .tifw; if your GIS program doesn’t accept that, try changing it to the more-commonly seen .tfw extension.

NOAA also has a free extension called Chart Viewer that lets you open BSB charts natively in ESRI’s ArcView and ArcGIS, and Leica Geosystems’ Imagine.



Additional ERDAS Viewfinder Utilities

Published at January 24, 2008 in coordinate conversion. 0 Comments

While a previous post dealt with using ERDAS Viewfinder to re-project raster images from one coordinate system to another, probably its most useful function, it does also have some other utilities. To start with, it has some satellite image viewing and enhancement capabilities, including multiband display, sharpening and softening, histogram equalization, and two standard deviation stretch. I won’t talk about those here, since I think its capabilities in that area are too limited to be especially useful, and I’ll probably cover more useful satellite image analysis programs in the future, But if you’re interested in those, you can take a look in the help file, or this handy tutorial PDF, which also describes how to use the general toolbar controls to zoom in/out and pan the map.

Instead, I’ll look at two other utilities, accessible from the Tools menu:

Continue reading ‘Additional ERDAS Viewfinder Utilities’



Reprojecting Raster Imagery II - ERDAS Viewfinder

Published at January 23, 2008 in coordinate conversion. 0 Comments

For a long time, I thought that the free utility ERDAS Viewfinder 2.1 had slipped through the cracks after the acquisition of ERDAS by Leica Geosystems, but it recently re-surfaced for me in a Google search. And that’s great (thanks, Leica!), because while Viewfinder is an OK geographic image viewer, especially when compared to the many alternatives now available, it does have one very handy capability: the ability to re-project a raster image from one coordinate system to another, and save the new image in GeoTiff format with the new projection/datum data embedded.

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