ArcGIS AllSource uses a high-performance drawing engine to ensure maps and scenes draw quickly with smooth symbols and text.
Because this drawing engine is different from the drawing engine used in ArcMap, there are important differences in the appearance of a map drawn in ArcGIS AllSource when imported.
The following sections describe some of these differences in drawing and why they occur.
Text and character marker antialiasing
In ArcMap, text and character marker antialiasing is controlled by the font smoothing settings configured in the machine's display settings. These settings are set per user and are not configured as part of the application.
In ArcGIS AllSource, these settings are configured within the application's options.
Because the ArcGIS AllSource drawing engine uses a different method of enabling text and character antialiasing, and the algorithms used to run this antialiasing are different, the text rendering and character markers may exhibit some differences when compared with the ArcMap display.
Coordinate rounding differences
In ArcMap, elements of the on-screen display are specified with integer coordinates. If the real coordinate of a feature (for instance, a line or a marker) does not lie exactly on that integer coordinate, it rounds up or down. This can result in some inaccuracies, particularly in the case of very thin lines or lines with very thin elements, such as cased lines. Lines whose sizes are less than one pixel at a given zoom level or display extent round up to one pixel.
In ArcGIS AllSource, the drawing engine can use subpixel coordinates to place and draw features on the map. This results in greater accuracy of feature placement and symbology.
However, if the map's symbology was originally designed in ArcMap, the appearance may be different in ArcGIS AllSource. This is especially evident in line symbology.
ArcGIS AllSource is capable of applying antialiasing to alleviate the effects of the changed appearance, but there are some cases in which antialiasing is not the best option. For example, using antialiasing can reduce drawing performance. Depending on the requirements of the map, this may be unacceptable. Also, for target export formats that use an 8-bit palette (such as PNG 8 or GIF formats), antialiasing may not be as effective due to the dithering required to render continuous progressions of color.
To alleviate this situation, manually change the size of the multilayer line symbol so that the line sizes are more appropriate. This also allows conversion for use with a target dpi other than 96 dpi (for instance, a target resolution of 120 dpi).
Design lines for a specific resolution (dpi)
To determine the appropriate line sizes for a given resolution, type the sizes of each of the symbols in the multilayer line symbol into the following formula. It is recommended to set the value for TargetResolution to reflect the desired minimum resolution at which the symbol will be used. Note that the hard-coded number of 72 in the examples below is the conversion factor of points per inch.
WidthInPixels = (LineWidth in points * TargetResolution in dpi)/72
If WidthInPixels is less than 1.5, the width should not be changed. If WidthInPixels is equal to or greater than 1.5, use the following formula to determine the edited width:
- Calculate the new width in points: NewWidthInPoints = (WidthInPixels + 0.5).
- Round NewWidthInPoints to the nearest integer (whole number) value that is not greater than NewWidthInPoints.
- Set the final line width to (RoundedNewWidthInPoints * 72) / TargetResolution.
Example: Design lines for 44 dpi
For example, if your desired resolution is 44 dpi, and your line symbol's width is 2.60, the math is as follows:
- Calculate the width in pixels.
(2.60 * 44) / 72.0 = 1.5888. Because WidthInPixels is greater than 1.5, proceed to the next step.
- Calculate the new width in points.
NewWidthInPoints = (WidthInPixels + 0.5) = (1.5888 + 0.5) = 2.0888.
- Round the result down to the nearest whole number.
NewWidthInPoints = 2.0
- Use the result to determine the final line width.
(2.0 * 72) / 44 = 3.27 points.
Example: Design lines for 120 dpi
In another example, if your desired resolution is 120 dpi, and your new line symbol's width is 2.60, the math is as follows:
- Calculate the width in pixels.
(2.60 * 120) / 72.0 = 4.333. Because WidthInPixels is greater than 1.5, proceed to the next step.
- Calculate the new width in points.
NewWidthInPoints = (WidthInPixels + 0.5) = (4.333 + 0.5) = 4.833.
- Round the result down to the nearest whole number.
NewWidthInPoints = 4.0
- Use the result to determine the final line width.
(4.0 * 72) / 120 = 2.4 points.
Simple symbols
Simple symbols (simple line symbol, simple fill symbol, and simple marker symbol) sometimes display in an inconsistent manner in ArcMap. Because of these inconsistencies, simple symbols may draw differently in ArcGIS AllSource. You may be informed of some of these differences in the log file that is generated when you import a map.
For instance, simple line symbols using a dash or dash-dot pattern do not honor a map's reference scale and draw with different spacing depending on the dpi requested. In ArcGIS AllSource, these symbols honor the map's reference scale and do not change with the requested dpi.
For simple fill symbols, the Style property is not available on the ArcMap user interface, but many developer samples and other third-party code snippets may create these symbols in a map. Styles other than esriSFSSolid are not supported in ArcGIS AllSource and result in an error in the import log.
For simple marker symbols, the behavior of the simple markers changes depending on the size at which they display, causing some variations in their size and shape.
ArcGIS AllSource always displays marker symbols at the requested size. In ArcMap, when a simple marker symbol's size is below a certain threshold, it will not draw any smaller. This means that when this threshold is reached, ArcGIS AllSource continues to display these symbols at an accurate size, whereas ArcMap does not, resulting in an apparent mismatch.
Caution:
In some cases, this means that small features that are overemphasized in ArcMap may not be visible in ArcGIS AllSource at smaller viewing scales.
Line decorations
For line symbols containing line decorations in ArcMap, such as line arrowheads, the decoration is not drawn when it is larger than the line length of the feature being decorated. The drawing engine used by ArcGIS AllSource always draws line decorations regardless of the size of the line. At some scales, this can lead to a more cluttered appearance than in ArcMap, but line decorations are drawn consistently and predictably.
Color
The drawing engine used by ArcGIS AllSource uses a color management engine. Because of this, some colors may not exactly match the appearance of the ArcMap display.
ArcMap does not use color management. In particular, you may notice differences in color when using the following:
- Colors defined in color spaces other than RGB (for instance, colors defined in HSV, CMYK, or grayscale)
- Algorithmic color ramps using HSV, CIELab, or LABLch algorithms
To minimize the color differences in a map service, change the monitor settings within ArcMap. This can be useful when authoring a map to import into ArcGIS AllSource.
To access the monitor settings, on any Symbol Properties dialog box, click the drop-down menu on the color swatch and choose More Colors.
On the Color Selector dialog box, click the arrow button and choose Monitor Setup.
On the Monitor Setup dialog box, change the Gamma setting to 2.2 and click OK to close the dialog box.
This instructs ArcMap to use a gamma value that more closely matches the color profile used by the drawing engine of ArcGIS AllSource.
Note:
This setting only affects the appearance of maps drawn by the user and the computer on which this modification is performed.
Font handling
Fonts are handled slightly differently in ArcGIS AllSource when compared with ArcMap. Specifically, text does not provide faux italic or faux bold styles as were rendered in ArcMap. You must use a font that has italic or bold styles to specify italic or bold. Faux italic and faux bold refer to situations where a font is not available in the bold or italic styles, or the combination of properties does not have a corresponding font installed. For instance, you may have Verdana Bold and Verdana Italic but be missing Verdana Bold Italic.
In the faux italic and faux bold styles, the original font is graphically skewed (italic) or thickened (bold).
This does not often correspond visually to the actual bold or italic version of the typeface. For some fonts (such as the Esri fonts designed for use as marker symbols), it does not make sense to display them in bold or italic styles. ArcGIS AllSource displays with only those fonts and font styles that are available on the system.
Font linking and font fallback
Fonts contain definitions for specific characters (the Latin letter A, Chinese glyph 
[qian], and so forth) in different character sets (such as Western Europe or Cyrillic) as determined by their creators. Font fallback and font linking are methods of displaying characters that do not actually exist in the requested font by drawing them in another similar font that does contain them. These methods are commonly used to display Latin characters with a font that only contains East Asian characters, or vice versa.
In cases such as these, the ArcMap display uses Windows GDI (graphics device interface, a graphics system built into Windows) to attempt to link to another font that contains the missing glyphs so the text string can display despite the missing characters. ArcGIS AllSource uses similar logic so that the string can still be rendered. Unlike ArcMap, ArcGIS AllSource fallback will render properly in output formats that reference fonts, such as PDF or EPS. In many cases, relying on fallback still results in less-than-optimal appearance due to mismatches in kerning or other characteristics between the original font and the fallback font (see the image below).
Because of these issues, relying on font fallback to render the proper glyphs is not a recommended practice for any map. In general, it is recommended that you use a font that contains glyphs for the character set you are attempting to use.
In this example, to ensure that the text renders correctly, use inline text formatting tags to switch to a font containing Thaana characters, such as MV Boli.
Note:
Use Diagnostic Monitor to view cases of font fallback. They are listed on the Log tab under the Debug event type. Filter on the string Font Fallback to display only font fallback events.
Font substitution
A similar technology, font substitution, is a method of displaying text in a different font when the requested font is not present on the system. For instance, if a map contains text that uses the font Helvetica but Helvetica is not installed on the machine, the text appears in Arial instead.
ArcGIS AllSource can use font substitution in the same way ArcMap can. However, in general, it is recommended that you ensure that the fonts used in the map are available on the machine that will use the map.