topic Re: Setting Initial zoom extent of map? in ArcGIS AppStudio Questions

Setting Initial zoom extent of map?

BradySmith — Mon, 22 Feb 2016 22:17:55 GMT

I am new to App Studio and am having issues trying to set the initial zoom extend of the app that I am viewing in Player. I assumed that the web map extent used in app would set initial extent similar to a web app but my app starts at the world view. Is there a setting or something wrong with my data make the extent show as planned?

Re: Setting Initial zoom extent of map?

MarikaVertzonis — Tue, 08 Mar 2016 03:43:03 GMT

The initial extent needs to be defined in the qml code of your app. To see an example you can download the Add and edit features sample in AppStudio Desktop Edition. Either use the search panel to browse to Groups > Sample Apps, or click New App and choose to create a new app from the Add and edit features sample (or almost any of the samples).

To demonstrate the use of extent in a much less complex simpler, follow these steps:

1. Click New App

2. Select Hello World (Runtime), enter a title and click OK.

3. Run the app (double click on it) to see that the app displays a world basemap at full extent.

3. Open the new app in Qt Creator.

4. Immediately above the line

Map {

add the following

Envelope {

id: myextent

xMax: -13630000

yMax: 4554300

xMin: -13640000

yMin: 4535200

}

5. After the line

id: map

add the following line

extent: myextent

Your code should look like this

6. Save and run your app. Now you should see that the app displays the map at the extent of San Francisco.

Re: Setting Initial zoom extent of map?

RuthannL1 — Wed, 09 Nov 2016 22:56:21 GMT

Hi Marika,

Thank you so much for the information about how to define the map extent; it was really helpful. How did you figure out the x and y values? Are those pixel values?

Thank you,

Ruthann

Re: Setting Initial zoom extent of map?

MarikaVertzonis — Thu, 10 Nov 2016 00:22:32 GMT

The values are map coordinates.

I have found the easiest way to get the scale and coordinates of my maps right is to have an app that shows the top right and bottom left coordinates. This screenshot shows this app:

I then zoom in and out and pan to the extent that I want, and then round off the coordinates that are displayed to something that suits my other app. The following code is what is used to display the coordinates on the map in the above app.

    Text {

       id: bottomLeft

       anchors.left: parent.left

       anchors.bottom: parent.bottom

       text: "xMin: " + map.extent.xMin.valueOf() + "<br/> " + " yMin: " + map.extent.yMin.valueOf();

    Text {

       id: topright

       anchors.right: parent.right

       anchors.top: parent.top

       text: "xMax: " + map.extent.xMax.valueOf() + "<br/> " + " yMax: " + map.extent.yMax.valueOf();

Re: Setting Initial zoom extent of map?

RuthannL1 — Thu, 10 Nov 2016 14:34:31 GMT

Awesome, Marika! Thanks; that worked perfectly! Using the text to call out the coordinates was a great idea!

--Ruthann