ProjectedPixels

Transformation, reprojection and rectification of raster maps with MapInfo^®
Version 1.1.1

ProjectedPixels is a program for the transformation, reprojection and linear rectification of digital maps to be used in conjunction with the MapInfo® desktop mapping / GIS software. ProjectedPixels can be applied only to raster images (e.g. scanned paper maps), which must be correctly georeferenced. All other types of MapInfo map layers can not be treated with this tool.

MapInfo^® offers extensive capabilities to transform coordinates between different coordinate systems, map projections, and geodetic reference systems. Digital maps in the form of vector graphics in various map projections and with different geodetic datums can be combined with correct locational alignment and can be displayed in a different projection easily.

Digital maps in the form of raster images, in contrast, can not be transformed into a different map projection with MapInfo (with version 8.0 and older versions), but can rather be displayed only in their native projection. The combined usage of multiple raster image layers with differing coordinate systems – e.g. from neighbouring UTM zones – is therefore problematic and error-prone. Starting with version 8.5 this raster transformation functionality has been newly integrated into MapInfo Professional, thus making the application of ProjectedPixels redundant.

But, with the ProjectedPixels add-on, you may utilize MapInfo's capabilities for projection transformations for your raster images as well. All the geodetic, i.e. "earth-related" coordinate systems usable with MapInfo can be applied as target systems for the reprojection of raster maps. Raster maps may even be transformed from a projection like UTM into a Long/Lat pseudo projection with perpendicular meridians and parallels of latitude ("Plate Carrée" projection; see below). However, the so-called "non-earth" coordinate systems can not be used as the source or target system of a transformation.

A precondition for the successful use of the program is the selection of a projection which is suitable for the area covered by the raster image, i.e. a projection which does not produce extreme distortions. The area depicted in the above maps for instance is too wide for the UTM projection and in the Long/Lat pseudo projection shows a considerable disproportion in scale for different parts of the map. Nevertheless, the large area displayed in the above sample maps clearly illustrates the way this program works.

The result of the raster image transformation mostly is not an exact rectangle, i.e. the new raster image will have void areas at the edges. The colour of these border areas is user-definable and could later be made transparent when displaying the map in MapInfo. Alternatively, the program also facilitates the cropping of the newly created image to a rectangle which is automatically made smaller in size, so as to avoid invalid border areas.

Any raster map that is to be transformed with ProjectedPixels must be correctly registered / georeferenced in the right "earth-related" coordinate system. The registration data must be stored in an accompanying MapInfo TAB file. The transformation process will then create another new TAB file for the newly created, transformed raster image file.

In addition to transformations into a different type of projection or a different coordinate system, the program may also be used to rectify raster maps. This means, raster maps with linear distortions, e.g. caused by oblique scanning, will automatically be orientated and aligned properly in the targetted coordinate system by rotation, scaling up or down, and angular rectification. The raster images resulting from this processing – presupposing identical coordinate systems – will then be well suited for combined usage, without the display faults and misalignments often encountered with non-rectified raster maps. However, this program is not usable for special, non-linear rectifications, like e.g. those required for the processing of aerial photographs.

After the transformation and rectification the new raster image could be scaled up or down within the same process. The number of pixels in height and width can be modified by a factor between 0.2 and 1.7. The registration data in the TAB file will be adjusted accordingly.

This add-on program utilizes the functions and algorithms of MapInfo for projection and datum transformations – as opposed to simple linear transformations or so-called "rubber-sheeting". Thus, an extensive transfer of data between MapInfo and the ProjectedPixels software must be performed. Therefore, and because of the complex nature of projection algorithms, the transformation of large files with this tool takes long processing times. To keep these as short as possible, instead of a geodetic projection transformation for every single pixel an interpolation mode can optionally be used, with which the true projection conversion is only applied to the sample points marking the corners of a grid of 10 by 10 pixel quadrants. For the rest of the pixels the new position is calculated by linear interpolation, which is much faster. In most cases, however, a quality difference between both transformation modes is not recognizable. Making use of MapInfo's projection algorithms results in the advantage of the great variety of available coordinate systems and the high degree of compatibility with other MapInfo maps and procedures.

File Format

The ProjectedPixels tool solely works with the BMP file format (Windows bitmap format) – or more precisely – only with uncompressed BMP files in 24 bit colour mode. If the raster images to be transformed do not already exist in this data format, then an image processing software will be required to carry out this conversion prior to the application of ProjectedPixels. The program can process files with a maximum size of about 1.5 GB (uncompressed).

There is also a German language version of this program.

Before bying this software product, you should have acquainted yourself thoroughly with the trial version (see below) and have verified that this works properly with your system configuration and is usable in the intended way.

System Requirements

The ProjectedPixels software can only be used in conjunction with MapInfo Version 4.5 or higher. The required operating system is MS-Windows® 95/NT4 or a higher version.

This software tool demands ample hardware ressources. Especially the amount of memory (RAM) used can be quite huge. After MapInfo has been started there should be additional free memory in the magnitude of 1.1 to 1.4 times the size of the uncompressed image file. Thus, the processing of an image file with 4000 by 5000 pixels requires additional 63 or 80 MB (depending on mode of operation) of free RAM. The availability of "virtual memory" is no adequate substitute for physical memory and may reduce the program performance significantly.

Price:    50.00   EUR  (single-user license; not including V.A.T.)

19% V.A.T. may need to be added for customers from a EU member country not having a EU V.A.T. reg. number.

Ordering procedures

Orders are accepted preferably in written or printed form (e.g. via fax: +49 5232 6918956). They should specify the following details:

1. Number of ProjectedPixels licenses to be purchased
2. Name of company / organization; for larger firms or institutions please do also name branch, department etc., for which the software is to be licensed.
3. Name of person in charge
4. Postal / fax / e-mail address and billing address if applicable
5. Your intended mode of payment:
   - Direct (electronic / wire) bank transfer
   - Sending a cheque or "international money order"
6. Only if applicable: Your European Union V.A.T. registration number
7. Any specific requirements you might have pertaining to purchase procedures

Dispatch

The dispatch of the software will preferably be done via e-mail (ZIP file). You may request postal delivery of the program (additional shipping and handling charge of 5.50 EUR for European countries, 8.50 EUR for overseas countries / air mail).
The invoice will be sent by fax; other options are postal delivery or transmission in an e-mail-attached PDF file.

Trial Version

A trial version of the program is available free of charge. This is functionally restricted and can only create output files up to a size of 800000 pixels (e.g. 800 x 1000 pixels). Apart from this restriction the trial version is exactly identical to the unrestricted version.

Download trial version   (File size: 306 KB)

After extraction of the ZIP file further information can be found in the "ReadMe" file.