ArcGIS for Mobile

Build Flex Apps for Unsupported Locale

2014-02-17T17:03:00.002+00:00

This is a bit off mobile topic but I think it's a very important issue that can be hard to solve for everyone that is building flex apps for other locale different from the common ones.

Since version 3.2 of ArcGIS for Flex, Portuguese (pt_PT) locale is supported, but if you change your Flex project to Portuguese you will get compilation errors. This article will guide you on how to overcome this problem with any language.

When you want to change the locale of your flex app, the first step is going to the project properties (right mouse click on your project's root). In Flex Compiler you will find in the arguments box:

-locale=en_US -source-path=locale/{locale} -keep-all-type-selectors=true

Change en_US for the target localization (in my case pt_PT ). Close Properties and compile. You will get the following error:

unable to open 'C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\frameworks\locale\pt_PT'

Now this is strange because ArcGIS for Flex supports pt_PT localization.

Checking ArcGIS Flex's Help, in the Localization section is stated:

"Adobe 4.6.0 supports 16 locales out of the box (see your Flash Builder install, for example, C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\frameworks\locale), while Apache Flex 4.10.0 supports 23 different locales. This still leaves seven locales supported by Esri that are not supported by the underlying Flex SDKs."

This Esri’s document also helps out on how to copy an existing locale, giving it a new name, but if you want to create a whole new localization files, let’s say, Portuguese, you will have to translate the copied files.

But first things first! Let’s start by copying existing locale files.

1. Open the windows command line with administration privileges.

2. Type the path of your Flash builder installation directory, for example cd "C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\bin".

3. In my case I will copy the existing pt_BR to a new pt_PT because the language is quite similar. This way I won’t have much work on translating the files.

Type copylocale pt_BR pt_PT. This will create localization files for pt_PT but with the same words as pt_BR.

If you want to copy, for example, from English to Hungarian you should type copylocale en_US hu_HU.

4. In the file explorer go to C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\frameworks\locale and you will find the new created folder pt_PT. If you don’t find it this could mean that you are not running command line with administration privileges.

5. Back to Flash Builder, in the project’s properties argument box, set the locale to pt_PT, like this

-locale=pt_PT -source-path=locale/{locale} -keep-all-type-selectors=true

6. Clean and compile the project. The error will go away and the localization strings will be set to the copied locale. Check, for instance, map tool tips and month names in calendar controls.

The next step is to translate the localization files with the correct words.

1. Go back to file explorer. In C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\frameworks\locale\pt_PT you will find ten .swc files. These files are where you will find localization strings.

2. In order to access and change this files you will have to extract, or unzip, every file with a normal packaging software like WinZip or 7Zip. You will probably get a “Access denied” error when unzipping the files, so copy every file to another location like your desktop.

3. Inside each extracted .swc you will find the folder \locale\pt_PT. Inside of this folder there are the localization strings.

4. With a lite text editor like Notepad++ edit each file to translate its string without changing the file format

5. After translating all the files you need to package the files again. Many posts on the web and even Adobe’s documentation point out to running a flex command line torecreate the .swc files but I couldn’t put it to work. I always got errors. So what I did was opening the original package files, one by one, with the packaging software and dragged and dropped the translated files back to its sources. Pay special attention to copy the files to the same location inside the package without changing the .swc original file structure.

6. The final step is to copy the translated .swc files back to C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.6\sdks\4.6.0\frameworks\ locale\pt_PT.

7. Compile and run the app.

Good Luck

ArcGIS for Windows Mobile Licensing

2013-12-11T12:36:00.000+00:00

One common question when implementing and designing a full field collection solution is, what type of licensing do I need in order to use ArcGIS for Windows Mobile (AGM).

In the early versions of AGM you would only get authorization with an ArcGIS for Server (AGS) Advanced Enterprise license, and you could only synchronize your data, between field and office, with a service publish on AGS. But starting with 10.1 if you have ArcGIS for Desktop you will also get one AGM license and you are able to synchronize your data with local Geodatabases.

Having said that, you can install, collect and synchronize your field data with your office data having a Desktop Licence or a Server Licence. Conditions following.

ArcGIS for Desktop

AGM is available with Basic, Standard and Advance licensing;
You get one mobile deployment for each desktop license;
If you need more mobile deployments you can purchase additional packs of 5 or 50 deployments;
You will be able to synchronize your field data with local Geodatabases with your ArcGIS Desktop software.

ArcGIS for Server

With an Advanced Enterprise license you will get unlimited mobile deployments and you will be able to create mobile capable services. This services are responsible for the synchronization of your data between your mobile and server;
With Advanced Workgroup and Standard Enterprise licensing you server is mobile ready but if you want to use AGM you will have to buy mobile deployment packs of 5 or 50;
The remaining Server licensing do not allow the use of AGM.

It is my understanding that the mobile deployment is the equivalent of field workers you have deployed on the field at one specific time or project. As an example, if you have one ArcGIS for Desktop license, you can have only one member of your team collecting and synchronizing data. If you want to have a team of 8 field workers collecting data, you will have to buy two packs of 5 mobile deployments.

ArcGIS Mobile 10.2 and the Windows Sensor and Location Platform

2013-11-04T11:20:00.003+00:00

Starting from Windows 8 the connection to the GPS receiver is no longer supported by COM Ports. Instead Microsoft developed what they call 'Windows Sensor and Location Platform'. This platform eases the connection to the many location techniques that are available on the device like Wi-Fi triangulation, IP address or GPS device. This is a quite new platform and a some hardware vendors support both modes.

O ArcGIS Mobile 10.2 does no yet support this functionality which will only be available on the second quarter of 2014.

For now there are two workarounds for this problem:

1. Install ArcGIS Mobile 10.1 or 10.2 with Windows 7 and connect to the devices COM Port;
2. Install ArcGIS Mobile 10.1.1 with the ‘Location API Connection Extension for AGM 10.1.1’ provided by Esri.

I have tested option 2 on two devices and it works fine. This extension does not work with ArcGIS Mobile 10.2.

This extension comes with a readme file that states 'Copy files inside ReleaseAssemblies Folder into C:\ProgramData\ESRI\ArcGIS Mobile\Extensions. ArcGIS for Windows Mobile tablet application will use Location API instead of COM port.'

If you don't have this path on your device, just create it and copy the files. Don't forget to restart ArcGIS Mobile App. Then go the GPS Settings and Status and check the Windows Location API Settings.

Good Work!

ArcGIS Flex application on Adobe AIR

2013-02-11T20:00:00.000+00:00

I have been doing some tests on how can one port an ArcGIS Flex Web Application to a desktop AIR App. To my surprise it was quite simple, fast and, most of all, everything worked on the first run.

This is what I did. My objective was to port ArcGIS Viewer for Flex to an ArcGIS AIR Application.

First of all I downloaded ArcGIS Viewer for Flex 3.1 source code, available on GitHub, and imported it to my Flash Builder workspace

Create a new Flex Project in File -> New -> Flex Project
Type a project name like ArcGISFlexDesktop and select Desktop (run in Adobe AIR)

For the next options go with the default.

Now that the project is created, expand folder src - (default package) and open the file ArcGISFlexDesktop.mxml. Also, on the FlexViewer Project, expand folder src - (default package) and open the file index.mxml

As you can see from the above image, the desktop application entry point is the s:WindowedApplication. As for the web application it’s the s:Application. So the first action is to copy the contents inside the s:Application tag, properties included, and paste them inside the s:WindowedApplication.

Next, copy the selected files (see image below) from the FlexViewer project to the ArcGISFlexDesktop project. The project structure must be the same for both projects.

The next step is to add all the modules to the project. Go to Project - Properties and then in the ArcGISFlexDesktop Properties dialog select Flex Modules and add the following mandatory widgets.

HeaderControllerWidget.mxml
InfoPopupWidget.mxml
WidgetContainerWidget.mxml
OverviewMapWidget.mxml
NavigationWidget.mxml
MapSwitcherWidget.mxml

I also added BookmarksWidget.mxml and QueryWidget.mxml but you can add all.

Finally you must copy the compiler arguments from the FlexViewer project to the ArcGISFlexDesktop project. Right click on the FlexViewer project and select Properties. Then go to the Flex Compiler tab and copy the text from the Addicional compiler arguments box. Paste this text into the same box on the ArcGISFlexDesktop project.

You’r all done! Press the run button and there you have it! An ArcGIS Flex AIR application.

To my surprise, porting a web Flex app to a Desktop AIR app was so easy that some questions came up. Why did Esri launch an ArcGIS runtime for Silverlight (WPF) and for Java but not for Flex. There are not even news or plans.

The ArcGIS runtime is intended to work in online and offline modes. For the offline mode map tile packages are used, so the app needs to access the local file system. Flex RIA has the capabilities to access local file system so I have no clue on why there are no plans on making an ArcGIS Runtime based on Flex.

Download the installer of ArcGIS Flex Viewer for Desktop

Add New Devices to a Mobile Provisioning Profile

2012-12-05T19:00:00.000+00:00

On my previous post I wrote on how to create an iOS relase build for ad-hoc distribution. But soon after I created and published a release build for a cliente, I was confronted with an aditional challenge. What if I want to add additional devices to the distribution package?

If you do a small search on the web and forums the news you’ll get is that you have to go through the complete packaging process again and again for each new device.

The news I have is: YOU DON’T!! What you have to do is update the existing mobile provisioning profile with the new device’s ID and distribute it along side with the original application's package.

Here’s a step by step.

Get the device’s Unique Identifier

The first step is to get the unique identifier of the device

Connect the device to the computer via USB
Start iTunes
In iTunes select, in the right column, the device
On the Summary tab press on the text of Serial Number

After pressing the text displays the identifier (UDID)
Press Ctrl + C (Windows) Cmd + C (Mac)

Add the new device to your company’s Apple account

Go to https://developer.apple.com/membercenter and log in

Press iOS Provision Portal

On the left column select Devices
At right press the Add Devices button

In Device Name field assign a intuitive name to the device.
Fill the the device’s ID field with UDID you copied earlier

If you need to add more equipment press the + button to the right

At the end press Submit and the new equipment is added

Associate the new device to the application’s distribution license

In the left column press Provisioning
Select the Distribution tab

In the row that corresponds to the distribution license press Edit on the right and then select Modify

In the Devices Section you should see the newly added. Select it, and all the devices you wish to assign to the license
Submit Press when finished

After you press Submit the license status may be in Process. If this happens press the F5 key to refresh the page. The status should switch to Active.

Press the Download button to download the license file. The file name is [LicenceFileName].mobileprovision

Distribute your licence and app files

There are two ways you can send the application and licence files to your users.

One is by email. Then the user can install both files with iTunes. First the licence file and then synchronize the application file.

The other way is to publish both files on a web server just like on this previous post.

In order to go with the second option, follow these steps.

Go to this previous post and follow the same last steps on how to configure the webpage
Then on the index.html file you must add also a link to the licence. The complete code is as follows

<ul>

<li>

Download Licence</a>

</li>

<li>

<a href="itms-services://?action=download-manifest&url=

http://[ServerName]/[AppFileName].plist">

Download Application</a>

</li>

</ul>

</body>

You also must add a new MIME type for the licence file

.mobileprovision application/octet-stream

This web page will have two links. One for the licence file and the other for the application installation package.

The application package is the same that was generated on this previous post.

Installing the application in new devices

To install the application, you must first install the licence and then the application. Send the link of the webpage by email.

To install the licence you must click on the Download Licence link
Install the licence clicking on Install

After the licence is installed. Press OK.

note: If when downloading the certificate an error message appears, this can mean that the device is not authorized to use this application, that is, the UDID of this device is not associated with the licence

Return to the web page and click Download Application. This will initiate the download and installation of the application.

And you’re done. If you need to add more devices, just repeat the process. At the end, on the webpage, replace only the licence file (.mobileprovisioning file).

Making a Release Build for Ad-Hoc Distribution of an iOS App

2012-10-24T10:34:00.001+01:00

Making a release build for the app store or for distributing an app in your company is always a pain in the neck. Apple insists on changing the process for each version of XCode, changing the rules, changing licences, once or twice a year. There are numerous articles and blog post on the web that will try to help you build a release version of your app. I say try because it’s hard to find an up-to-date article that will fit your XCode and Mac OS version.

So, this is my contribution to the confusion of articles on making a release build for an iOS App.

On the 29th of August of 2012 with XCode 4.4, Mac OS Lion 10.7.4 and iOS 5 these are the steps on making a release build for Ad-Hoc distribution of an iOS app.

First go to https://developer.apple.com and log in. The page will look like this

Register Devices
The devices to which you intent to install your app need to be registered in your account.

Click on iOS Provisioning Portal

Click on Devices and the on Add Devices

To add a Device you need any name and a Device ID. To get the Device ID you have to

Connect your device to your Mac

Open Itunes

On the summary page

In there you will see the Serial Number of your device

Click on the Serial Number and you will see the Device ID

Click command-c (Mac) or ctrl-c (Windows) to copy it to the clip board. You can then paste it on the iOS Provisioning Portal or send it by email to whoever is registering your device

Give a name to the device and the Device ID and click Submi. You can register up to 100 devices.

Create an App ID

Your app must have an AppID

Click App IDs. On the tab Manage click New App ID.

Write a intuitive name for your App ID in the Description

Select your Team ID. You should have one from your Apple Developer License

The Bundle Identifier must be the same as in your Project. Go to XCode to get it

Submit

Create the Distribution Provisioning Profile

On the same page click on Provisioning on the left, then the Distribution tab and then New Profile button

Select Ad Hoc

Choose a intuitive profile name

Click New Profile button

After submitting the profile it will be available in the profiles page. Once it is active, should take a few seconds (must refresh the page), you can download it.

After downloading the profile you must install it on XCode. You can drag and drop the file to your XCode icon

After this the XCode’s Organizer will open and you can check for the profile

Create the Distribution Archive

Now back to XCode. Select the Project and the info tab.

In the configuration Table add a new configuration. Click the plus sign to duplicate the Release configuration

Name the new configuration Ad-Hoc. It will look like this at the end.

Now, still in the Project view, go to Build Setting tab.

The Ad-Hoc configuration is in the Code Signing Identity table.

In the row named Ad-Hoc and sub-row named Any iOS SDK click on the AdHocTestApp row to select a profile

And select the profile you created on the Apple Developer Portal

Next, click on the Scheme selection button on the top left

and select Edit Scheme

Select Archive on the left.

Select the Ad-Hoc Build Configuration and click Ok

You are now all set up ( Finally!!! ) to create the distribuition package.

Click on the Scheme selection button and select iOS Device

Build you App

After it finishes select Archive

The Organizer window will open after the archiving finishes

Now click on Distribute

Select Save for Enterprise or Ad-Hoc Deployment

On the next window choose your Ad-Hoc profile and click next.

Select where you want to save the .ipa package, I chose the desktop.

At this point you have two choices regarding Save for Enterprise Distribution check box

Install the app through iTunes. Leave it uncheked

Download and Install the app on the iPhone through a webpage. Check it.

If you choose the first option the file AdHocTestApp.ipa will be created on the desktop and you can now drag and drop it to you iTunes and then synchronize the app. The Profile you created is embedded in .ipa package. And you're done! Congratulations!!

Or not... If you choose the second option there are still a few more steps. So keep reading.

Choose a name for the package

Check the Save for Enterprise Distribution option

Type the URL of the location of the .ipa in your server

Add a title

I haven’t tested the subtitle and image URLs yet.

Click save.

This will generate two files in your desktop

AdHocTestApp.ipa

AdHocTestApp.plist

You have to copy this files to your server to the location you specified above

The next step will be creating a web page form which you can donwload the app. This is the simplified version.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>AdHoc Test App</title>

</head>

<body>

<ul>

<li>

<a href="itms-services://?action=download-manifest&

url=http://MyServerName/iOSAPP/AdHocTestApp.plist">

Tap here to install AdHocTestApp

</a>

</li>

</ul>

</body>

</html>

Notice that the href link is not the .ipa but .plist

You are all done!

note: in my case I am using an Microsoft server and I had to add the corresponding MIME Types for the .ipa and .plist. (no screen shots, sorry)

Go to IIS Manager

Locate you web site folder

Right click and select Properties

Open HTTP Headers tab

Click on MIME Types button at the bottom

Click New... button and add these two

.ipa application/octet-stream

.plist text/xml

Now, on your device, navigate to the page and download and install the app.

Good Luck!!

ArcGIS and PhoneGap

2012-09-26T21:46:00.000+01:00

Here is my first test with Adobe PhoneGap and with the ArcGIS SDK for Javascript. I’ve created this app to run on Android, but the same html code I’m creating here can also be used to create any other PhoneGap supported OS, like iOS or Windows Phone.

I will go through the configuration of PhoneGap on Eclipse, creating then a Hello World. Next I will create a map application using the ArcGIS SDK for Javascript inside Eclipse. At the end I have the code and the .apk so that you can install on your device.

Configure the PhoneGap development environment

First go to PhoneGap donwload page and download the latest PhoneGap available version. In this case 2.0.0

http://phonegap.com/download

Then just follow the instructions on the Getting Started Guide for Android. This guide will help you on how to configure your Eclipse and build a Hello World application

While editing AndroidManifest.xml file I added only the following settings

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

At the end if you want to run you Hello World App on a real device and do not succeed, try this instructions on Android Developer http://developer.android.com/tools/device.html

Create your First ArcGIS Map

Now that you have your Hello World let’s start to build an ArcGIS application.

In this example I want to make an app that will show me the real time earthquake location on a map. Besides that I want my app to zoom into my current location.

Surfing a bit on www.arcgis.com I found some maps related to earthquake information like this one. This map has a layer that shows the most recent earthquakes above the magnitude of 2.5. The service url is

http://ags.pdc.org/ArcGIS/rest/services/global/pdc_active_hazards/MapServer/4

So to add a ArcGIS map to your PhoneGap app lets first get a sample from ArcGIS API for Javascript page.

http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples/mobile_simplemap.html

Copy the code to your index.html file in you Eclipse project

After this add the PhoneGap’s JavaScript ibrary reference to the index.html file

<script type="text/javascript" charset="utf-8"

src="cordova-2.0.0.js"></script>

Run the app on a device or emulator and... voila! You are in Paris! Magic!

If you get the error message “The connection to the server was unsuccessful. URL=file:///android_asset/www/index.html” try this.

Now let’s change the initial extent to the whole world. If you simply change this line with your new extent.

var initialExtent = new esri.geometry.Extent({

                             "xmin" : -14161000,

                             "ymin" : -477000,

                             "xmax" : 11669000,

                             "ymax" : 8094000,

                             "spatialReference" : {

                                   "wkid" : 102100

                             }

                       });

Add the Earthquake Map

Now add the earthquake map. For this you will add a FeatureLayer to the map and also the ability to identify the earthquake on tap. Replace the dojo.connect(map, "onLoad", function(evt) block with the following

dojo.connect(map, "onLoad", function(evt) {

//add a feature layer

var content = "<b>MAGNITUDE</b>: ${MAGNITUDE}<br /><b>DEPTH</b>: ${DEPTH} Km<br />${DATE_TIME}";

//create a Info Template

var infoTemplate = new esri.InfoTemplate("Details", content);

map.infoWindow.resize(150,80);

//create the FeatureLayer

var featureLayer = new esri.layers.FeatureLayer("http://ags.pdc.org/ArcGIS/rest/

services/global/pdc_active_hazards/MapServer/4", {

mode : esri.layers.FeatureLayer.MODE_ONDEMAND,

      outFields : ["MAGNITUDE", "DEPTH", "DATE_TIME"],

      infoTemplate : infoTemplate});

//add a click event to the FeaureLayer

dojo.connect(featureLayer, 'onClick', function(evt) {

//select the clicked feature

      var query = new esri.tasks.Query();

      query.geometry = evt.mapPoint;

      featureLayer.selectFeatures(query, esri.layers.FeatureLayer.SELECTION_NEW);});

//add the FeatureLayer to the map

map.addLayer(featureLayer);

});

You must add the dojo imports. After dojo.require("esri.map");

dojo.require("esri.layers.FeatureLayer");

dojo.require("esri.tasks.query");

Run the application and tap on some points

Get the Location and Zoom

To get your device location, both PhoneGap and ArcGIS API for JavaScript use the W3C’s GeoLocation API.

First you must make sure you have the following settings

in app/res/xml/config.xml you must have the following tag in the plugins section

<plugin name="Geolocation" value="org.apache.cordova.GeoBroker"/>

in app/AndroidManifest.xml you must have the following tags

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_CO

MMANDS" />

Then in your index.xml file inside dojo.connect(map, "onLoad", function(evt){ after map.addLayer(featureLayer); add the following lines

if (navigator.geolocation)

{

navigator.geolocation.getCurrentPosition(zoomToLocation, locationError);

navigator.geolocation.watchPosition(showLocation, locationError);

}

And then the corresponding listener methods

function locationError(error) {

switch (error.code) {

case error.PERMISSION_DENIED:

alert("Location not provided");

break;

case error.POSITION_UNAVAILABLE:

alert("Current location not available");

break;

case error.TIMEOUT:

alert("Timeout");

break;

default:

alert("unknown error");

break;

}

}

function zoomToLocation(location) {

var point = esri.geometry.geographicToWebMercator(

new esri.geometry.Point(

location.coords.longitude,

location.coords.latitude));

map.centerAndZoom(point, 5);

}

And there you have it! All is calm now around Portugal. But if you live in Puerto Rico or the Dominican Republic things are shaky over there.



Download Android apk
Download code

GPS Required Fix Type

2012-06-16T12:51:00.000+01:00

So you are configuring a ArcGIS Mobile Project in ArcGIS Mobile Project Center. You check the General tab, the View and Edit Form tabs and all is very intuitive and straight forward. Until you get to the GPS Settings tab. To be more precise the Required Fix Type.

It is not easy to find information on what to these options mean. The only place I could find was on the ArcGIS Mobile SDK reference pages.

So I compiled here the meanings and applications of each. But first of all, what is Required Fix Type? The Required Fix Type is a way to ensure that the location of the features collected in the field will be preformed by GPS and that the minimum GPS quality required will be the one you select here. Lets say you choose the option Real Time Kinematic. This way, you will only be able to mark the location of a feature in the map if the type of signal you are getting on your mobile device is coming from a RTK receiver.

   ESTIMATED or Dead reckoning is the determination of a location based on computations of position given an accurately known point of origin and measurements of speed, heading and elapsed time. Dead reckoning coupled with GPS positioning provides a powerful navigation solution. GPS positioning provides highly accurate "points of origin" when exposed to sufficient satellite signal strengths during a trip. Dead reckoning can be used to "fill in the gaps" when there are insufficient GPS signal strength to obtain an accurate position.

FIX indicates a standard GPS signal, or Standard Positioning Service (SPS) is being used. SPS is the standard specified level of positioning and timing accuracy that is available, without qualification or restrictions, to any user on a continuous worldwide basis. The accuracy of this service will be established by the U.S. Department of Defense based on U.S. security interests.

   DIFFERENCIAL indicates that Differential GPS is being used to proved increased accuracy over Standard Positioning Service (SPS). This technique uses a network of fixed ground based reference stations to broadcast the difference between the positions indicated by the satellite systems and the known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount.

   REAL TIME KINEMATIC or (RTK) satellite navigation is a technique used in land survey based on the use of carrier phase measurements of the GPS, GLONASS and/or Galileo signals where a single reference station provides the real-time corrections of even to a centimeter level of accuracy. When referring to GPS in particular, the system is also commonly referred to as Carrier-Phase Enhancement, CPGPS. This GPS technique uses the radio signal (carrier) to refine it location initially calculated using DGPS. The receivers are able to reachy this level of accuracy by performing an initialization, that requires data from at least five common satellites to initialize on-the-fly (in motion) tracking at least four common satellites after initializing.

   FLOAT REAL TIME KINEMATIC ( Float RTK) is very similar to the fixed RTK method of calculating location, but is not as precise, typically around 20 cm to 1 meter accuracy range. This decreased accuracy is offset by increased speed, since the time consuming initializaton phase is skipped.

   PPS FIX indicates that Precise Positioning System, encrypted for government use is being used by the receiver. PPS is the most accurate positioning, velocity, and timing information continuously available, worldwide, from the basic GPS. This service will be limited to authorized U.S. and allied Federal Governments; authorized foreign and military users; and eligible civil users. Unauthorized users will be denied access to PPS through the use of cryptography.

For more info on GPS and ArcGIS Mobile check my other post on this here

What types of GPS does ArcGIS for Windows Mobile support?

2012-04-07T19:52:00.000+01:00

Recently someone at work asked me “What types of GPS standards does ArcGIS Mobile support?” My answer was immediate, “GPS? Aaah! Is that my phone ringing?”

So I rushed back to my PC and started searching. Here is the result of my investigation.

First of all, what is GPS? Very briefly, GPS ou Global Positioning System is a space-based satellite navigation system that provides location and time information anywhere on or near the Earth. There are two main frequencies that the systems broadcasts position information, one for military proposes and one for civilian use. The first as better accuracy and the civilian one can have errors of up to 100 meters. Each GPS satellite transmits location messages in a protocol known as NMEA or National Marine Electronics Association.

To improve the accuracy of the civilian GPS applications there are enhancements to the GPS system. These are A-GPS, RT-GPS, D-GPS, WA-DGPS, RTK and PP-GPS … and some more. Here are a few.

A-GPS or Assisted GPS is a way a mobile device can use to get a faster GPS satellite fix. This technique uses network resources such as GSM or Internet to get an approximate position. It is the responsibility of the mobile device to support this feature.

image: http://blog.prosig.com

D-GPS or Diferencial GPS can bring accuracy up to 10 cm. D-GPS uses a network or fixed ground-based reference stations to broadcast the difference between the positions indicated by the GPS satellite systems and the known fixed positions. The connection to this ground stations is done by a network connectivity. The device receives and processes the normal GPS positioning messages and the applies the offset given by the nearest ground stations. There are European DGPS Network and United States DGPS Network, among others, that you can connect to.

WA-DGPS or Wide Area DGPS (also called SBAS - satellite-based augmentation system) is similar to D-GPS but the offset is calculated and transmitted by orbiting satellites to ground stations. The process for correcting the position on the device is similar to D-GPS. EGNOS is the European Geostationary Navigation Overlay Service and WAAS - Wide Area Augmentation System developed and maintained by the Federal Aviation Administration in the US.

PP-DGPS is Post-processing used in Differential GPS to obtain precise positions of unknown points by relating them to known points. The GPS measurements are usually stored in computer memory in the GPS receivers, and are subsequently transferred to a computer running the GPS post-processing software. The software computes baselines using simultaneous measurement data from two or more GPS receivers.

RTK or Real Time Kinematic is a real time offset calculation technique that can bring accuracy up to millimeters. This technique uses a second receiver on the device (usually UHF) to receive the correction signal from ground stations.

There are a few more correction techniques and protocols that help you improve your GPS accuracy, but these are the most common.

Now, from all the above which does ArcGIS for Windows Mobile support?

First of all ArcGIS for Windows Mobile supports only the NMEA protocol.

Then the final answer is... all of them! Execept PP-DGPS (Post-processing DGPS).

It is up to the mobile device to support and proccess the signals corrections and enhancements. The final corrected NMEA sentence is then forwarded to a COM port on the device. Then on ArcGIS Mobile GPS settings menu you just select the correct one.

The ArcGIS for Windows Mobile commons questions page also has a few more answers like What GPS devices does ArcGIS for Windows Mobile work with? or Does ArcGIS for Windows Mobile support differential GPS?

http://www.esri.com/software/arcgis/arcgismobile/common-questions.html

Also here is a post on the ArcGIS Blog about Connecting your GPS Receiver to ArcGIS Mobile

Here are a few references on GPS
http://blog.prosig.com/2010/04/12/everything-you-ever-wanted-to-know-about-gps-but-were-afraid-to-ask/

http://en.wikipedia.org/wiki/Global_Positioning_System

http://en.wikipedia.org/wiki/Differential_GPS

http://en.wikipedia.org/wiki/Real_Time_Kinematic

http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System

http://en.wikipedia.org/wiki/European_Geostationary_Navigation_Overlay_Service

http://www.navcen.uscg.gov/

http://www.effective-solutions.co.uk

http://en.wikipedia.org/wiki/Satellite_Based_Augmentation_System#Satellite_Based_Augmentation_System

http://www.gpsinformation.org/dale/nmea.htm