MapOCX Pro v7.1 Frequently Asked

Technical Support Questions and Answers

1.         I can see the MAP of the USA, but when I zoom in, there are no streets.

A)  Are the data paths are pointing to valid folders containing valid data files?  Even though you may have set the paths either at design time, or as part of a FormInitialise, FormCreate, FormLoad event, it’s possible that in your IDE event sequence, a setting of Autoload=True is causing a configuration (.CFG) file to be loaded afterwards, thus resetting what you thought your data paths were.  The best way to confirm that may be to have a button that echoes the data paths at the time when this error seems to occur.

B) Does the DataSource property correspond to the data files the above paths are pointing to?  For example, if your DataSource=2, but the data folders you are pointing to contain TIGER data files, then the roads files will not be loaded.

C)  Not common, is it possible that you have reset the visibility of the street level data?  You might have set such visibility to a value lower than the 2-mile default, through the appropriate SetOption call, in which case roads will not become visible until your zoom scale is lower that the SetOption value.

2.   Every time I try to execute my project, I get the error message that the product is unregistered.

If you have a developer’s license, you have received a Vendor Code and Vendor Password.  You need to use them to register your copy of the control as a developer’s copy.  In most development environments, this can be accomplished by right-clicking on the control, selecting Properties and then the installation tab.  In other environments, this may be done directly in the properties inspector, or by setting the VendCode and VendPass properties in one of the form initialization events.

3.   Can I use the TIGER and the GDT data at the same time?

No, unfortunately this is an either/or situation.  You can toggle between the two using your data source property.  The new MapTivate mapping/GIS tool from Undertow, uses an open architecture which allows you to combine data from different sources.

4.         How do I switch between TIGER and GDT data?

There are two things that determine what data will be used to render the maps.  One is the DataSource property, and the other is the actual data your data paths are pointing to.  To switch between the two data sets, you need to set DataSource=1 (or ZP5_TIGER, if the enumerated values are accessible in your IDE) to use the TIGER data set,  DataSource=2 to use the USA GDT dataset, DataSource=4 to use the Canadian GDT data set and DataSource=6 to use the USA & Canadian GDT data set.  Remember that the controls data paths need to be pointed to the folders containing the corresponding data, and you need to have the license to use the selected dataset.  Also be sure that the .SIG file is located in the data directory.  The .SIG file tells the OCX what type of data it can expect to find.

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7.         Why can’t I find an address, I know it’s there?

A number of different causes may result in your not being able to find an address, when you search for it using MapPro61.

A)         Although you may know the address is physically there, it is possible that the data is not in the databases provided with the control.  Undertow makes every effort to provide you with good quality data (in particular with the GDT quarterly updated data), however, it is still possible that some addresses have not made it into the database.  The problem may be more with the TIGER dataset, which only provides with 60-80% address coverage, depending on the geographic area.

B)         Is it possible that the street name you are searching for is a “local” name, but the official name of the road/street is different?

C)         It’s possible that you are using an abbreviated form that is not supported by the control and/or the databases.  Although most, accepted abbreviations for Prefixes and Suffixes are supported, it’s possible that you have found some obscure one that is not.  Look at the address and see if using the unabridged version of the address works.

D)         Are you using the format as specified in the user’s manual and/or the control’s built-in dialogs? 

E)         Are your data paths set correctly, and are all the required files in the specified folders?

8.         What can I use for Reverse Geocoding?

Use the FindClosest function.  Just be judicious with the specification of the search radius, if you do not want your searches to consume much of your CPU time.  Depending on the region of the US, a setting of .05 (250ft) may be desirable.

9.         What is the best way to use the OCX in an Internet Environment?

There are many ways to achieve that.  The simplest way may be to create your map server in the ASP environment. In doing so, remember to set your Vendor Code and Vendor Password, and setting your data paths correctly, upon initializing the ASP code.  The most common mistake seems to be forgetting to perform these two, necessary steps.

10.     What is the best way to use the OCX in an Internet Environment?

See sample ASP source code supplied with your developers kit.

11.     Which is better to use, SetItemBitmap, or SetItemLocalBitmap?

Well, that depends on your application.  Using SetItemBitmap makes use of a handle to the loaded bitmap, which means it can be used for many different items without using l resources, but the user is responsible for managing those handles.  SetItemLocalBitmal, on the other hand does not require any management.  It shoud also be noted that MapPro takes a look at the list of Loaded LocalBitmaps, and if the specified bitmap is already loaded, no additional copies are loaded.

12.     I’m drawing a line using the DrawLine function, but it’s not showing up.

A common mistake is that users forget that the device contexts are transient.  If a dc “X” is used for the canvas at the time the map is painted, there is no guarantee that the same dc # corresponds to that canvas a few CPU cycles later (unless the canvas is locked).  The only certain way to endure that the line is drawn on the surface of the map is to draw the line inside the PaintAfter even using the dc that is being used to paint the map at that precise time.

13.     When I generate a route, it picks a really strange route.  It doesn’t look like the least number of turns, or the fastest.

This misunderstanding usually comes from the definition of Fastest, Shortest, etc. within the context of MapPro61.  This explanation may help you understand.  The fundamental simple routing algorithm uses an evaluation of Euclidian distance to the goal point and the length of the path traversed from the start point, to that goal point.  From each node in the calculated network, a choice exists for each segment leaving the node, and a decision needs to be made as to which choice to use.  The process is extremely complex and many factors are in play when generating a route.

14.     How does the registration process work for my users?  Can I pre-register the software for them and just supply them with a code?

When the OCX first runs on a client system, it pops up a generic dialog box that asks them to register the software for quality assurance.  They then have three options, 1) Register over the Phone, 2) Register over the Internet, and 3) Register later.  They have 15 days to register the software.  There are a number of reasons for the registration.  First, and foremost, it automates the licensing process and it is needed so that we can give developers less restrictive and better priced options, where they pay only for copies of their product that have been deployed and are being used, rather than making them pay for fixed blocks of licenses which may never be used!  The second reason is to help us provide technical support to registered users, where applicable, and finally it allows us, and the developers, to know where the tool is being used.  Is some situations, our customers make more money since they can track where their software is being used and charge their customs accordingly.  This is a transparent process to the end user.  Currently, there is no way to pre-register users since the registration code is based on information from their computer.

15.     Can I use multiple controls on a form?

No, only one instance of the control is permitted on a form, in a given project.  If multiple map views are needed in a single application, at the same time, the user should use the new, powerful, DirectView method to paint additional maps on user-selected control surfaces.

16.     When using it in an internet environment, I don't have access to the events, how can I use the searching and reverse geocoding?

There are powerful “List Object” parallels to the original visual methods, to achieve those same functions, in MapPro.  GeoFindFirst, GeoFindNext and GeoFindClose should be used for reverse geocoding, and FindRouteFirst, FindRouteNext, FindRouteClose should be used to calculate routes in non-visual environments.

17.     How can I import my own data, or can I change a street?

Although the control does not give you the ability to load third party data, you can create your own map files and load them to augment the mapping data sets provided with it.  For detailed directions on how to do that, take a look at the appendix of the user manual, describing the Street Editing mode of the control.  (Note that as described in the appendix, you may set your application app so that these additional street data files that you create are automatically loaded when the application starts.

18.     There's a signification pause when I redraw the maps, it seems slow.

There could be a number of factors affecting the redrawing of your maps.  It’s impossible to tell all the reasons without being intimately familiar with your system and development environment.  However, a very common situation is that one of your data paths is pointing to an invalid path, like a disconnected network drive or path.

MapOCX Pro v7.1 General Commonly Asked Questions and Answers