To install, keep all files in original folder. This will be the programs location, so put it in a convenient place. Double-click "setup.exe" Setup will install the program and create a startup folder called "MapGrid."
MapGrid Reclass is self-explanatory and quite easy to use. However several points are worth noting:
1. To avoid errors and confusion, the upper and lower limits of new categories should be mutually exclusive. For example, if the first category includes all grid values between 0 and 1000, then the next category should begin at 1001. The program calculates the new categories sequentially from the classification table, thus if category 1 includes values 0 to 1000, and category 2 includes values 1000 to 2000, the cells with values of 1000 will end up in category 2.
2. If category values are mutually exclusive, categories can be listed in any order in the classification table. For example, the first new category might include all values from 5 to 10, while the next category could include all values from 0 to 4.
3. To create a binary map (0's and 1's) when intermediate values are to be the 1's, use three categories. For example, if an original grid has values from 1 to 12 and only the region of "6's" is to be kept, make the first category of 1 to 5 equal 0, the second category of "6's" equal 1, and the third category of 7 to 12 equal 0.
4. The cells with any values not included in the classification categories are given the "nodata value" in the new grid. That is, their original values are gone in the new grid. If a grid mask is desired (a map of a single region), the values of interest can be reclassified as "1's," and the remainder will default to nodata. (Note: if the grid is of byte, integer or long data type, and contains an exponential nodata value of extreme size (eg. -3.40282346638529E+38) the new grid will not be able to contain that nodata value. Grids of single or double data type have no such problem.)
5. A maximum of 12 new categories can be created. If more than 12 categories are needed, make two or more reclassified grids. Divide the categories among the new grids -- any un-reclassified values will show as "nodata" on each grid -- and the new grids can be recombined via an overlay procedure to capture all the new categories on a single grid. (This program will not do the overlay.)
6. This program does not create or display map legends. It is up to you to keep track of your values and their meanings.
7. Reclassified grids will be geographically identical to the original grid and will automatically have the same data type and the same nodata value.
8. If you open a second (or other subsequent) grid, be sure to click the buttons for new "Grid Info" and a new display for the newly opened grid. Otherwise your new "active grid" will not match the displayed information or map.
9. Very large grids take time to load and process, so be patient. They also require a lot of RAM, so make sure your system has adequate resources before processing such files.
MapGrid Reclass is an open-source program subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this program, you can obtain one at http://mozilla.org/MPL/2.0/. This program uses MapWinGIS Open Source ActiveX Map Control. A copy of its license is located at: http://mapwingis.codeplex.com/license/ The MapWinGIS ocx file is available at http://www.mapwindow.org/
This program was created using Microsoft Visual Basic 2010 Express as a Windows Forms Application. For those interested, the program source code is provided as a Word document in the program download folder. Questions or comments can be sent to: rkendallo41@gmail.com .
