Optimizing map content for performance—ArcMap (2024)

Setting up your data

Choosing the format in which to store your data is often a balanceof many factors, including the needs of your organization or users,purpose of the data, size of the data, analysis or data maintenancerequirements, and so on. However, in terms of speed, shapefiles aregenerally fastest, followed by personal geodatabases, then filegeodatabases. For optimal map performance, the data in your mapshould reside locally on the computer that is being used to view itrather than on a remote machine. For maps that will typicallydisplay relatively small areas of large datasets, serving data viaArcSDE will yield significant performance benefits over storingthis same data in files.

Avoid personal geodatabases for any situation where you must havemultiuser access or are serving the map, since this format was notdesigned for these purposes.

Here are some additional considerations for setting up yourdata:

• Keeping all projections the same—If possible, keep all data in a single projection and use the sameprojection in the data frame when working in ArcMap. This isparticularly important to keep in mind when editing data orauthoring data to be served. When all layers are in the sameprojection, the performance penalty incurred by on-the-flyprojection calculations can be avoided.
• Working with joined or related data—Data from appended fields accessed through joins and relates can beused to symbolize and label features, to perform queries, and formany other operations. However, accessing data through joins andrelates can slow performance. See Essentials of joining tables for details on optimizing tablejoins. In addition, you can export the data to new featureclasses that contain the joined or related information.
• Using attribute or spatial indexes—If the data source allows it, index any fields used for querying orrendering. Indexes are specific to each data format. For moreinformation, see Modifying indexes in shapefiles by adding a spatial indexand A quick tour of setting a spatial index (geodatabases). Thegeoprocessing framework also provides a tool to create attributeindexes: the Add_Attribute_Index tool.
• Simplifying data—Use simplified or generalized versions of layers when displaying atsmaller scales. For example, a detailed map of world coastlines maydraw slowly at full scale. If this layer is simplified to havefewer vertices and line segments, it will draw much faster withlittle difference in appearance at a small scale. In addition,simplified data can improve performance for querying and identifyoperations.

Optimizing layers, rasters, and layouts

One of the first and easiest steps you can take is to look throughyour map and remove any unused layers and data frames. Then, checkboth the page layout and data views and ensure that your mapdocument is clear of data frames and layers that are unrelated tothe map's purpose. In addition, in layout view, look through yourmap elements and remove any unnecessary ones.

Once you've done this, the sections below provide additionalconsiderations for improving performance. For information onsymbology and performance, see Optimizing map symbols for performance.

• Use basemap layers to optimize drawing performance. See Working with basemap layers for more information.
• Hiding certain layers and features automatically—Two of the best ways to optimize layer drawing are to draw themonly at appropriate scales and use attribute queries to avoiddrawing unnecessary features.

  If you don't need to display a certain layer when your map is at a certain scale, turn on scale dependency. For example, if you are zoomed out to a country boundary, you can use scale dependency to have a detailed city transportation layer turn off automatically. You should draw detailed layers only at larger (zoomed-in) scales. If a detailed layer needs to be drawn at smaller scales, use simpler symbology at that scale to expedite drawing. To learn how to set scale dependency, see Displaying layers at certain scales.

  A definition query can act as a filter to limit the amount of dataon the map. For example, if you are creating a map of a state andyour feature class contains data for the entire country, you canuse a definition query to display only those features that fallwithin the state's boundary. To learn how to use definitionqueries, see Displaying a subset of features in alayer.

• Building a local cache of map data—If you're working with data stored in a geodatabase or from anArcIMS feature service, building an ArcMap feature cache canoften speed up common mapping tasks. The ArcMap feature cache allowsyou to temporarily store the features in the current map display inArcMap to your local machine's memory. Because retrieving thefeatures from local memory is a fast operation, using the feature cachewill often result in performance improvements. Some of theactivities that can often benefit from a feature cache include drawinglarge or complex datasets, labeling, editing, selecting features,retrieving the same features for multiple layers on a map, anddrawing features using a definition query. To learn more about thefeature cache and when to use it, see Working with the feature cache.
• Displaying rasters—To speed up raster drawing, you can employ several techniques, suchas keeping the display quality as coarse as possible, using anappropriate resampling method, and displaying the raster in itsnative projection rather than projecting it on the fly. Inaddition, you should buildpyramids for your raster. Pyramids can speed up the display ofraster data by retrieving only the data at a specified resolutionthat is required for the display.

  For a list of other ways to improve performance when working withrasters, see Improving the display of raster data.

• Improving performance in layout view—While in layout view, look at the border of your data frames. Roundcorners, backgrounds, and shadows will slow down performance.Eliminating these effects and setting these properties to squarecorners can improve drawing performance of the data frame in layoutview. You can change these properties by right-clicking the dataframe, clicking Properties, then clicking the Frame tab.

Optimizing maps to be served with ArcGIS Server

The tips for optimizing maps also provide performance benefits for authoring maps to be served with ArcGIS Server. In addition, here are some other tips specific to maps to be served. For more tips, see Map authoring considerations.

When serving maps, design the map for the intended audience. Include the appropriate layers and symbology, but do not include anything that the audience does not require for this application. Remove any map layers or data frames that are not needed for the intended application. Consider making only a few layers visible by default, since users can turn on layers as they need them.

While using a cached map service is always the fastest way to serve map services because the map is only rendered once at the time the cache is created, creating a cached map is not always practical for dynamic or changing data. When it is not appropriate to rely on cached maps, following the tips in these sections of the help will also improve performance while preparing dynamic map documents and delivering them through your map service.