Designing and creating mobile maps using ArcGIS for Desktop

When designing and creating mobile data and maps for use in the field, you should consider how the field workers will be viewing map data and editing features. Field workflows are different than those performed in the office. Factors that can influence the design of your mobile map include the following:

• Data considerations
• Work environment conditions (for example, direct sunlight, rain, snow, dust, and darkness)
• Form factor of the mobile devices (including display resolution, key, rocker and/or stylus interaction)
• Symbology to be uses for the map features
• Device memory
• Storage constraint

To address these factors, you can design mobile maps with a purpose and take into consideration the workflows, tasks, devices, and field environments with which the mobile projects will be used.

The following sections illustrate some key mobile map design considerations and details on how ArcGIS for Windows Mobile applications work with ArcGIS for Desktop map symbology. This topic focuses on operational map layers, since this type of map layer is used heavily in field work for editing and viewing. For more information about mobile maps, see Overview of a mobile map.

Data considerations

Mobile maps often contain operational layers for editing or for providing read-only reference information. For example, pole inspection maps often contain pole, transformer, and transmission layers, which may be updated in the field. Pole inspection maps also include parcel or block boundaries, street centerlines, address information, and even other vector layers as supportive background data.

Because of the potentially large size of data cached on the device, it's important for performance and storage reasons that all background data be as small and simple as possible. To simplify background data and limit its size, first consider whether the background layers are required to complete the field task for which the application is designed. If background layers are required, use simple symbology to represent features, and use the generalization tools in ArcGIS for Desktop to simplify the shape of background layers.

If you want to include raster data or satellite imagery as a basemap, you should also consider the extent to be included in your mobile project because the size of the basemap is also limited by the storage constraints of your field devices (for more information, see the Storage Constraints section of this topic). However, to include a basemap, you can use ArcGIS for Desktop or ArcGIS for Server to create tile packages or tiled datasets and use them as basemaps in Mobile Project Center. For more details, see Creating a tile package or tiled dataset.

Work environment conditions

You should have a field user's mind-set when designing a map. Consider the fieldwork environment, which may be a stressful environment (such as disaster management), or other conditions including intense sunlight, darkness, rain, or sub-zero snow conditions. Lighting conditions have a direct impact on the colors and symbols you choose when designing your map. In the office, you are designing maps under ideal conditions. The artificial light and large monitors used in the office enable the use of a wide range of colors and symbols. However, this is something often solved by experimentation on the mobile device used in the field. The following tips can be used as a general guideline:

• Design simple mobile maps with exaggerated contrast.
• Use scale dependency to control the amount of information display.
• Use symbology that is familiar to the field crew. For example, use shield symbols for highway features.
• Make background layers as transparent as possible (you can achieve this by setting layer transparency).
• When displaying parcels, districts, or polygon features as background information, avoid using fills. If fills are unavoidable, use simple colors or set transparency for the layer.
• Use gray tones where possible and limit the amount of text.

Remember that what looks good in the office on a desktop computer may not look good outside on a mobile device.

The following map examples demonstrate the difference between office use and field use:

Device form factors

Consider the form factor of the mobile device you are targeting with your application and the format in which maps will be displayed (portrait or landscape). Most Pocket PC devices have a resolution of 320x240, but they can vary considerably. The monitor you're using when designing your maps is most likely 1024x780, 1280x1024, or higher. Resolution has a direct impact on scale dependency. It's very important to add scale dependency to the layers in your map so that you display layer content only when it's needed. This improves the clarity of your maps, and more importantly, it reduces the time it takes to draw the map.

You should set a visible scale for each layer.

Tip:

ArcGIS for Windows Mobile applications do not honor the reference scale you set on a map, so symbols do not scale as you zoom in and out.

When designing for the device form factor, shrink the size of the map display window in ArcMap to mimic the size of the device, and set scale dependency accordingly. You need to take this into consideration when determining the appropriate marker symbol size and line symbol thickness, as shown in the following screen shot:

Map symbology

The symbols you choose to display geographic information will determine how effective the map is in your mobile application. If you're rebuilding an existing application or if paper maps are used in the field, use symbols that are familiar to the field-workers if possible. Keep the symbols simple, and remember that contrast is important in conveying the right information on your map. The challenge is that you're designing a mobile map using a desktop application that is meant for authoring maps to other desktop or web applications, not field applications.

When designing the symbology to use, determine whether you're going to use a desktop or a server workflow, since one symbology supported by a mobile service may not be supported by a mobile cache created from the mobile geoprocessing tool, or vice versa. For more information about both workflows, see Workflows for ArcGIS for Windows Mobile.

Symbology in ArcGIS can be categorized into point , line polygons, and text. ArcGIS for Windows Mobile supports a subset of the ArcGIS symbol sets (where reference scale is not supported), so you need to choose a size based on the scale at which the point feature is to be displayed. Supported symbology is summarized as follows (with details in the following tables):

• All simple symbols are supported.
• 3D symbols are not supported when data comes from a mobile service.
• All 2D symbols are supported by the desktop workflow and most are supported by the server workflow In both workflows, symbols may be downgraded (for example, a marker fill symbol downgraded to a simple fill symbol).
• Labels with SQL query, expression, or multiple classes are not supported by either workflow.

Point symbols

Point symbol type		Supported by mobile service	Supported by mobile cache
2D	Simple Marker	Yes	Yes
	Character Marker	Yes	Yes
	Arrow Marker	Yes	Yes
	Picture Marker	(downgraded)	Yes
3D	Simple Marker	No	Yes
	Character Marker	No	Yes
	Marker Symbol	No	Yes

Line symbols

Line symbol type		Supported by mobile service	Supported by mobile cache
2D	Simple Line	Yes	Yes
	Marker Line	(downgraded)	(downgraded)
	Picture Line	(downgraded)	No
	Has Line	Yes	(downgraded)
	Cartographic Line	Yes	Yes
3D	Simple Line	No	Yes
	Texture Line	No	No

Tip:

It's best not to use line symbols with decorations since they get downgraded.

Polygon symbols

Avoid using a fill symbol for polygons if possible, as it often adds complexity to your map that is not needed on a mobile device.

Polygon symbol type		Supported by mobile service	Supported by mobile cache
2D	Simple Fill Symbol	Yes	Yes
	Picture Fill Symbol	(downgraded)	(downgraded)
	Marker Fill Symbol	(downgraded)	(downgraded)
	Line Fille Symbol	(downgraded)	(downgraded)
	Gradient Fill Symbol	(downgraded)	(downgraded)
3D	Texture Fill Symbol	No	(downgraded)

Text symbols

ArcGIS for Windows Mobile supports both labeling on a layer in ArcMap and annotation that is stored in a geodatabase.

Tip:

Use annotation for text instead of labeling, since labeling on the fly consumes battery.

Caution:

Annotation stored in a .mxd (map document) file is not supported.

When labeling a mobile map, consider the font you choose and how it will look on the device where the map is displayed. The text rotation angle is also important. For example, Tahoma 8pt font is a good font and size for labeling features on a Pocket PC. However, if the text is rotated, consider using a larger font size. Depending on the mobile device and its resolution, rotated labels may not display as clearly as you'd like.

ArcGIS for Windows Mobile does not display labels defined by SQL query, annotation defined by definition query, or justification properties for a map layer. The application also does not support labeling using an expression. For example, a text expression that concatenates several fields to form a street address is not supported. To accomplish this, you need to create a new field and calculate the value of the field equal to the concatenation of the existing fields.

Device memory

If you have Windows Mobile device as your target field device, you should take into account the available memory on the device. This is particularly important if you use a BLOB field or a raster field to store images. Since the image files are written into the memory stream, they can potentially consume all the memory available during this process. To work around this issue, you can create an attachment for the feature class and attach image files (as well as video and other types of files supported by your system) to the attachment feature class.

Storage constraint

Field devices, particularly Windows Mobile devices, usually have less storage space than a desktop machine. At the point of map design, start considering the amount of data to deploy to a field device based on its available storage space. For example, avoid adding multiple attachments to the map and deploying them together to a field device if the attachments are not needed by your field workers to complete their work.

In a mobile project, offline basemaps are usually the data that consume most of the storage space. Offline basemaps (tile packages, tiled datasets, and StreetMap for Windows Mobile) must be stored on the device, and their sizes can easily go up beyond gigabytes. To reduce the size of an offline basemap, you can clip only the area that is needed for the field work or reduce the level of details. You can also add a basemap to your project by reference (see Adding offline basemaps for more information) so that it only needs to be deployed once to then be shared by multiple projects (if applicable).

On the other hand, if your field workers' devices have connectivity in the field, you can include online basemaps in your mobile map. When your field crew browses to a location with an online basemap at a given scale, only that area at that scale is cached temporarily in the device. The cache is cleared when the project is closed.

Note:

To learn more about selecting a basemap, see Choosing basemap layers.

If your device supports an external Secure Digital (SD) memory card, you can use it to expand the storage space on the device.