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Urban zone maps, forest management charts and plans at the scale of 1: 500 are usually printed with black ink only, i.e. ideally they consist of black lines on the white background. In practice, the lines are not really black and the background has already lost its whiteness. That's why the 256 level gray scale is in use at scanning as a rule.
It is usually possible to find a brightness level suitable for unambiguously line extraction from the grayish background. Not always, unfortunately. For example a map sheet folded in four could be badly faded from above. Pencil corrections in materials are even worse – spots and abrasions of the dirty background may be darker than light pencil lines.
The Unsharp Mask tool makes pencil strokes darker and "tears them away" from the dirty background but simultaneously it may reveal the dirtiest spots, fill sharp angles between crossing lines, and "glue together" lines, which are spaced closely. In other words, there will be a lot of additional editing after you apply it.
The Local Contrast Enhancement tool operates in another way. It makes the difference between pale lines and the background more distinct without line form distortion at crossings and unwanted line agglutination. The even name of the tool indicates that it enhances brightness difference between lines and the adjoining local zone of the background.
The tool is applicable for processing of grayscale and TrueColor images. It is particularly useful for partly faded maps and for vectorizing of pencil corrections.
The tool is controlled by the following parameters:- Factor - controls magnitude of object / background contrast enhancement. Make it maximal for grayscale images. As for color ones, select a factor value so that color objects you want to extract wouldn't become too dark;
- Mask size - controls the size of zone to enhance object / background contrast within. Too small mask size may lead to loss of thin lines whereas excessively big mask can distort near by lines;
- Noise part - enables you to eliminate the effect caused by isolated dark pixels. The more is this value, the less possible is contrast enhancement for "dirt" on defective zones of the background. On the other hand, excessively big parameter value may lead to loss of small or thin useful lines;
- Threshold - controls the minimal level of object / background brightness difference sufficient for contrast enhancement.
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Rasterization with subsequent vectorizing may be useful for averaging of big vector data massifs. For example, it is possible to average GPS-tracks recorded at the same route in this way. But it is necessary to have an empty raster layer for the operation. Coordinates and the size of this layer should be the same as ones of the layer of tracks.
The following sequence of operations may be used now:- Vector data import with new project creation;
- Creation of an empty raster layer;
- Vector data rasterization;
- Image processing: Diffusion => Contrast Enhancement => Color mode change for black-and-white => Image Thinning;
- Vectorizing of the resulting thin lines;
- Export of the averaged vector.
The new "Create Image" command generates and adds a new image, which completely corresponds to the project field.
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Urban zone maps or facility plans at the scale of 1: 500 are usually overladen with information. At that, text data are often printed above linear and polygonal objects. Actually, they tear these objects into parts making automatic or even semiautomatic vectorizing impossible. The same is true for lines of special types that comprise text characters and other additional elements.
On the other hand, linear objects represented in this way must be vectorized as uninterrupted lines with minimal possible number of vertices according to the digital model requirements. Actually, all additional elements should be ignored at vectorizing and taken into account later, at attributive data input.
There may be also a lot of dashed lines in the image – these objects have never been unbroken from the very beginning but should be vectorized as continuous lines. Use of the Line Joining utility after automatic vectorizing is ineffective as text symbols or relief elements suitable for joining are often located alongside of stroke ends. It means that the share of erroneous joinings will be inadmissibly high, and there will be superfluous vertices in lines.
So, instead of breakup joining, you may run the utility, which looks for sets of short line segments that form long smooth or broken curves. At line forming, the utility may ignore crossings with other lines and text, short gaps, and adjacent "rubbish" vector objects.The utility is being developed, this version is an intermediate one.
The Autodetect Dash Lines utility is intended for extraction of long linear objects from results of automatic vectorizing. In the image, these objects may be represented by lines of special types that comprise text symbols, gaps, or additional design elements.
The utility is organized as a four-step Wizard. Parameter selection at every step should be done in the Preview mode. Some parameters may be specified by means of direct pointing of line segment samples on the screen.
Step 1. Length selection for line segments that will be used as source elements at recognition of long linear objects.
Step 2. Specify maximal permissible distance between polyline segments that should be joined together and maximal line deviation within its rectilinear parts.
Step 3. Unification of line segments at nodes. Discarding of short prominent (noise) segments.
Step 4. Saving – attributes recognition results to the specified layer.
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Polygonal coverage extraction from results of automatic vectorizing requires a series of preliminary operations as a rule. It consists of polygon boundary cleaning from "adhered" vector "rubbish" (line defects, vectorized text, etc.), mending of gaps in lines, and separation of linear and polygonal objects.
This process accelerates notably if elements of closed cycles are attributed to an individual vector layer just after automatic vectorizing. At that, one should consider possible occurrence of short gaps in polygon boundaries.This utility extracts boundaries of adjoint polygonal objects from results of automatic vectorizing. Unlike Autodetect Lake utility, it suits for polygons in soil maps, plot charts, etc., i.e. for all polygonal objects having rather long and complex boundaries adjoint to other polygons.
It may be reasonable to apply Raw Line Filtering beforehand (for example, to delete bridges and agglutinations in narrow zones of polygons). Breakup Joining may be also useful sometimes as it removes long gaps in lines. In that case, limit permissible angle between segments to be joined to avoid unwanted joining with text fragments and other rubbish objects.
If the "Delete original polylines" option is on, the utility divides vectorizing results in two parts – lines recognized as polygon edges and everything else.
It is necessary to run the Create Polygons utility after optimization and correction of polygon edges' form as it provides transfer from the node-chain model to the polygonal one.
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The most widespread type of polygonal coverages is a set of closed polylines where boundaries of adjacent polygons are represented by coinciding line parts. It means that any coinciding boundary is always duplicated. Moreover, you have to draw the third line on a "decorative" layer if the boundary must be represented by a special line type. Editing of such constructions is extremely unhandy and the probability of error generation is high.
Another way of polygonal coverage description is the node-chain model with centroids. It becomes more in use now as powerful computers can support this technology. Editing convenience, steadiness, and consistency of this model win it more and more advocates.
Besides, some advanced free GISes support this model and this is another argument to its credit.Function of the utility is reverse to one of the Create Polygons utility. Starting from common boundaries in the polygonal coverage, it forms a set of segments attributed to an auxiliary layer that form the chain-node model of the coverage. Polygon identification in this model is based on special point objects - centroids always situated inside initial polygons.
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The Generate Profile Points utility forms 3D-points at crossing of isolines with lines of the specified layer, e.g. rivers. Contour elevation values saved as attributes should be copied to polylines' Z-values before you run the utility. Use the Copy Z to/from Database utility for this purpose.
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A large share of geoinformational work being in progress in Russia now is connected with integration of independently prepared materials. Mutual conformity of these data leaves much to be desired. To solve the problem, we have updated one utility and added a new tool to the package.
The process starts with vector data transformation based on an arbitrary set of reference points. The set should consist of unambiguously identifiable points of the reference layer and the layer being transformed. Then you apply the improved "Adjust polyline segments within given radius" option of the Topology Correction utility. Unfortunately, there are always line parts that differ from the reference layer greater than the radius you have specified.
To complete the work, use the new Line Matching tool, which collapses prominent line parts (we call them "lenses" for their typical form). Final decision in every particular case belongs to the operator of course. If the "lens" should be collapsed, one touch of the tool is sufficient.The new Line Matching tool brings prominent line parts to conformity with lines of the specified reference layer. Run the tool in the following way:
- Select reference layers (lines attributed to these layers are unchangeable) and layers of lines that will be corrected in the Parameter bar of the tool. Note, that there should be common vertices at crossings of lines of reference and work layers otherwise line matching becomes impossible. If common vertices are missing, apply the "Generate shared vertices at polyline crossings" option of the Topology Correction utility first.
- Left click within a "lens" between lines of a reference and a work layer collapse the "lens" and thus matches the lines. Brief blinking of the "lens" indicates successful line matching.
- The Cut out Subprojects utility – pop-up tips and controls descriptions are added to the bottom of the dialog box.
- The Contrast Enhancement tool works faster as it has become multithreaded.
- Grayscale and color image conversion into black-and-white ones has now an adjustable brightness threshold. You may decide where to draw a distinction between black and white. The tool has Parameter bar and Preview mode for provisional estimate of conversion results.
- Adjusted Custom Tools may be now imported from another ET project.
- Time account is improved. Previously the program didn't take stock of time spent for work in modal windows, dialogs of utilities, and the time of background processing (utility execution in inactive documents). In particular, it concerned attribute assignment to marked objects as this is an operation being executed in a modal window. Besides, the program wrongly measured time for documents divided into several views.
- Name index is added to blocks for search acceleration. Loading of a complex qualifier became almost two times faster. Another one internal improvement had the same effect. As a result, loading of big projects with complex qualifiers takes notably less time.
- Semiautomatic tracers are improved. After several indications of the right direction at forks they move actually faultlessly.
- The Raw Line Filtering utility is amended. First of all it concerns analysis of defects – adhesions, bridges, and X-joints. These defects are difficult to tell one from another in complex images with numerous intercrossing lines, but their automatic processing is absolutely necessary for quick vectorizing of such materials. Defect detection has become more reliable now and we continue to develop the utility.
- Functioning of the Topology Editor in the Cleaning mode is changed. Dragging of the tool cursor deletes all vertices within the effective radius.
- The Orient Rivers utility is improved – now the program considers short segments attached to a polygonal object (lake) or another river as tributaries. Some errors are corrected (including wrong calculation of river "elevation" at a small increment of relief contours).
- The Positioning Control page is added to the Project Properties -> View and Editing dialog box. It contains the "Animate the next object" new option among other things. Another new option - "Display object after inscription generation during…" available through Parameters button of the Object Attributes dialog box gives you time to check correctness of attribute input with automatic generation of inscriptions.
- New functions of the Attribute Tables dialog box.
Export to the CSV format is added to the Attribute Tables dialog box (Edit -> View Attributes to open).The table will be exported as you see it – visible columns, the current sequence of records, and the current filtering (if any).
Besides, an additional line is added to the table for quick table filtering by any column. Use of >, <, = symbols is permitted, the register is unimportant. The "attribute contains this sub-line" condition is on by default.
Column selection is available through the drop-down list (click the Choose Columns button to open). Individual and group selection is provided for custom and built-in attributes, column refreshment happens at once, etc.
- Filling along polyline by the Decorator tool is improved. Vertices of the reference polyline may be deleted now by Z key stroke. Previous vertex deletion by Backspace also remains. Besides, snapping to vector objects is added.
- The folder of projects-prototypes may be specified now on the Project Settings -> Locations page. Previously, you could do it only at standard prototype set-up or manually, in the registry.
- Tool-tip location on the screen is changed and the pause required for their appearance is increased. Margins are added for screen output of the project field and images for better navigation within edge zones of documents.
- Import of MID files is improved: every "defective" line (suppose, someone has missed a quotation mark in an attribute name, etc.) does not interrupt the operation, and the program describes the error in the log-file.
- The bug is corrected, which could cause program termination at reading of GIF-files with a local palette.
- The bug is corrected – the program didn't refresh the "Rasterize points as circles with given radius" parameter at selection of rasterization strategy.
- Timer blinking defect is removed.
- The bug is corrected – the "Move tool up / down" arrows didn't work in the Customize User Tools dialog box
- The bug is corrected – the "Move tool up / down" arrows didn't work in the Customize User Tools dialog box.
- The bug is corrected – preview of subject layer extraction could show "dirt". Image opening filter didn't see jpeg-files.
- Wrong functioning of the Generate Points on Lines utility is corrected – it worked so slowly that seemed hung when the number of points was big (including interrupt response).
- The bug is corrected, which could cause program termination at image transformation (adding / rotation).
- The bug of MID-import is corrected: the program incorrectly imported attributes if tabulation was used as the delimiter (it skipped the first value if it was empty and shifted all the next attributes with wrong type correspondence, attribute lost and "renaming" as a result).
- The bug is corrected: vertex contraction could generate lines with zero number of vertices if node forming was selected for snap. It resulted in termination or incorrect work of many utilities and tools afterwards.
- Reading of color tile files in the tiff format is corrected.
- The bug is corrected – line doubling could happen if node forming was selected for snap.
- The bug is corrected – the program broke even a single line at vertex contraction if node forming was selected for snap.
- The bug is corrected – program termination at an attempt to change object layer with the Z-tool.
- The bug is corrected – it was impossible to change line type in Z parameters.
- The bug is corrected – the program didn't read / write pgw/gfw files.
- The bug is corrected – a reduced image copy (in use for quick screen output of the image) existed only till image editing.
- The bug is corrected – the Resample down utility didn't work.
- Writing / reading of tiff files with jpeg conversion is restored. The function was lost beginning from 8.6 version.
Easy Trace Pro 9.2.1985
The number of new utilities and tools in this version is relatively small. Our efforts were mainly aimed to program code transfer into a new compiler version. This operation gave rise to many errors and thus required total testing of the package.
Besides, we did much in backfitting of utilities for topographic map processing introduced in the previous version