Tuesday, October 25, 2005

Minimal Enclosing Circle

The Minimal enclosing circle algorithm finds the smallest circle that contains all given points. Found the following 2 pages that had a nlogn and a n^2 algorithm.

http://www.cs.brown.edu/people/tor/java/mec/ O(nLogN) http://www.personal.kent.edu/~rmuhamma/Compgeometry/MyCG/CG-Applets/Center/centercli.htm linear time

Why is such an algorithm important? For graphics and games (collision detection). Bomb damage assesment (minimum size of bomb to take out a set of targets)

Thursday, October 20, 2005

PortForward.com - Free Help Setting up Your Router or Firewall

http://www.portforward.com/ Offers help setting up port forwarding on your router or firewall. Many Internet users are not aware of how to configure their router or firewall in order to use applications like Peer-to-Peer file sharing (PtoP), Internet Games, Web serving, FTP serving, WebCams, IRC DDC, and Instant Messaging such as AIM, ICQ, Yahoo and MS Messenger.

Wednesday, October 19, 2005

Tech Recipes - Tips for various Comp related Stuff

http://www.tech-recipes.com/ This cookbook of computer knowledge contains almost a thousand recipes of step-by-step tutorials, tweaks, hacks, and hints. Feel free to browse the latest recipes, read our blog, or grab one of our many RSS feeds.

Thursday, October 06, 2005

GCTP (General Cartographic Transformation Package)

Index of /ftp/software/current_software I was looking for the GCTP (General Cartographic Transformation Package). Found it at the above site. The page also has other interesting tools and sources, which are described below. (This text was taken from a read-me on that page). Its also available from http://edcftp.cr.usgs.gov/pub/software/gctpc/ --------------------------------------------------------------- File Description *.bat DOS Batch Execution Macro *.dat Program which usually includes FORTRAN source code, IBM job control language, and sample input data. *.dta Direct access file for IBM compatible personal computers *.exe Program executable for IBM compatible personal computers *.for FORTRAN program code for IBM compatible personal computers *.ftn FORTRAN program code for midi / mainframe computers *.jcl Input for Program COMPCAL *.pnt Output for Program COMPCAL *.txt Program documentation converted to ASCII format. *.wp Program documentation in original WordPerfect 5.1 format. *.ps Program documentation converted to PostScript format. *.tif Graphic Display File in TIFF format *-um.* Users Manual Technical Instruction *-sd.* Software Documentation Technical Instruction air Long Distance Mileage Computations compcal Comparator Calibration (W5356) convdem DEM Coverage Conversion (C language) corpscon_4.12 UTM, State Plane, and NAD Coordinate Conversions (USATEC version 4.12 for DOS and Windows 3.X) corpscon_5.11 UTM, State Plane, and NAD Coordinate Conversions (USATEC version 5.11.08 for Windows 95, 98, 2000, and NT) dlgtodxf DLG to DXF Format Conversion for Auto CAD gctpc2 GCTP converted to C programming language - version 2.0 (28 projections, 19 ellipsoids, 1 sphere) gctpv2 General Cartographic Transformation Package (GCTP) version 2.0.2 (21 projections, 19 ellipsoids, 1 sphere) geotrans Coordinate conversions between datums, projections, and grids (NIMA version 2.2.3 - also available from Internet site URL h290 Complete Comparator Calibration j898v2 GCTP Driver Test Program (uses gctpv2) l176v2 General Map Projection Transformation (uses gctpv2) nad1927 North American Datum (NAD) of 1927 State Plane Zone Parameters nad1983 North American Datum (NAD) of 1983 State Plane Zone Parameters plane-pc Interactive Grid Coordinate Conversion for Personal Computers spload Program to Load State Plane Zone Parameter ASCII files into Direct Access Files v5xstd Installation wizard for CORPSCON version 5.11.08(also available from Internet site URL http://crunch.tec.army.mil/software/corpscon/corpscon.html w5501 Geodetic Position and Inverse

Cartographical Map Projections

I found the following pages useful to understand projections. The following page has information about the arguments for the different projections. http://www.ciesin.org/metadata/documentation/guidelines/spatref.html This page also has a lot of information about what makes up the different projections. In addition, it also has information regarding the formatting and syntax for the well known text format (WKT) for each of the projections: http://www.remotesensing.org/geotiff/proj_list/ OGR Simple Feature Library: The OGR Simple Features Library is a C++ open source library (and commandline tools) providing read (and sometimes write) access to a variety of vector file formats including ESRI Shapefiles, S-57, SDTS, PostGIS, Oracle Spatial, and Mapinfo mid/mif and TAB formats. It allows one to create projection information and write and read the WKT formats for projections. I am currently working on reading ERDAS Imagine's projection information and converting them into the OGRSpatialReference format.