Map services are not drawn on web maps completely, leading to inaccurate feature count when performing a spatial selection.
上次发布: September 21, 2020ArcGIS API for JavaScript
漏洞 ID 编号
BUG-000131304
已提交
June 2, 2020
上次修改时间
June 5, 2024
适用范围
ArcGIS API for JavaScript
找到的版本
3.32
操作系统
Windows OS
操作系统版本
10.0 64 Bit
状态
Will Not Be Addressed
开发团队已考虑过该问题或请求,并决定不会解决该问题。 问题的“其他信息”部分可能包含进一步说明。
附加信息
When a layer in a map service is used as feature layer in on-demand mode:
1. FL fetches less features per tile request because maxRecordCount is 2000 (whereas the layer has 4938 total features).
2. FL also applies feature generalization based on the current map scale. As a result, features that are too small after generalization have no coordinates at all.
3. When a selection query is executed for the full extent, only features that have coordinates match the query. So, only a subset of features are selected.
4. As you zoom in, number of features fetched and selected change because: number of request tiles changes, maxAllowableOffset changes.
When layer in a feature service is used as feature layer in on-demand mode:
1. FL fetches more features per tile request because it uses resultType=tile and that increases the maxRecordCount to 4000
2. The layer is editable. So, feature generalization is disabled - resulting in features having all their coordinates regardless of map scale.
3. When selection query is executed for the full extent, all features available in memory match the query.
This is the reason for the difference in feature count when selecting features in a map service layer versus a feature service layer. This can be fixed in couple of ways:
1. Configure the layer in "snapshot" mode so that the layer will fetch all features up front.
An example is provided below,
featureLayer = new FeatureLayer(
"https://essanalytics.esri.com/server/rest/services/SMRoads/FeatureServer/0",
{
mode: FeatureLayer.MODE_SNAPSHOT
}
);
2. Enable WebGL for the web application by setting "esri-featurelayer-webgl" has flag to true and configure the layer as not editable.
An example is provided below:
featureLayer = new FeatureLayer(
"https://essanalytics.esri.com/server/rest/services/SMRoads/FeatureServer/0",
{
mode: FeatureLayer.MODE_ONDEMAND,
outFields: ["*"],
editable: false
}
);
解决办法
Use a feature service.
If ArcGIS Web AppBuilder is used, use the map server URL instead of the layer URL.