<PAGE>
                                  EXHIBIT A-3


                                PROMISSORY NOTE
                               (ACQUISITION LOAN)


$10,000,000.00                                                     June 3, 1998

     FOR VALUE RECEIVED, the undersigned, ANALYTICAL SURVEYS, INC., a 
Colorado corporation (referred to herein as the "MAKER"), hereby promises to 
pay to the order of BANK ONE, COLORADO, N.A. (the "LENDER"), at the offices 
of Bank One, Colorado, N.A., the Agent, on or before the Acquisition Loans 
Scheduled Maturity Date, TEN MILLION DOLLARS AND 00/100 CENTS  
($10,000,000.00) or if less, the aggregate unpaid principal amount loaned as 
Acquisition Loans to the Maker by the Lender  pursuant to, or otherwise 
outstanding under, that certain Credit Agreement, dated as of June 3, 1998 
among the Maker, Bank One, Colorado N.A. as the Agent, and certain Banks (the 
"CREDIT AGREEMENT").  Capitalized terms used but not defined herein shall 
have the meanings given to them in the Credit Agreement.

     The Maker further agrees to pay and deliver to the Agent, when and as 
provided in the Credit Agreement, interest on the outstanding principal 
amount hereof at the rate and at the times specified in the Credit Agreement.

     This Note is the Acquisition Loans Note made by the Maker pursuant to, 
and is subject to, all of the terms and conditions of the Credit Agreement.  
Maker may repay and reborrow amounts evidenced hereby as Acquisition Loans 
under the Credit Agreement.  Reference is made to the Credit Agreement and 
the documents delivered in connection therewith for a statement of the 
prepayment rights and obligations of the Maker, and for a statement of the 
terms and conditions under which the due date of this Note may be accelerated.

     This Note evidences the obligation of the Maker to repay all sums 
Advanced pursuant to the Credit Agreement by the Lender and any holder hereof 
to the Maker as Acquisition Loans.  The Lender and any holder hereof shall, 
and are hereby authorized to, record on the Acquisition Note Record attached 
hereto, or to otherwise record in accordance with its usual practice, the 
date, principal amount, applicable interest rate or margin and Interest 
Period of each Acquisition Loan and the date and amount of each principal 
payment hereunder; PROVIDED, HOWEVER, that neither the failure to so record 
nor any error in this recordation shall affect the Maker's obligations under 
this Revolving Note.

     In addition to, and not in limitation of, the foregoing and the 
provisions of the Credit Agreement, the Maker further agrees, subject only to 
any limitation imposed by applicable law, to pay all expenses, including 
reasonable attorneys' fees and legal expenses, incurred by the Lender or 


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any holder hereof in endeavoring to collect any amounts due and payable 
hereunder which are not paid and delivered or otherwise satisfied when due, 
whether by acceleration or otherwise.  This includes the Lender's or holder's 
reasonable attorneys' fees and legal expenses whether or not there is a 
lawsuit, including attorneys' fees and legal expenses for bankruptcy 
proceedings, appeals, post-judgment collection services and court costs.

     The Maker, for itself and for all endorsers hereof, hereby waives 
notice, demand, presentment for payment, protest and notice of dishonor.

     This Note and the rights of the Maker and the Lender are governed by the 
laws of the State of Colorado.

     IN WITNESS WHEREOF, the Maker has executed and delivered this Note on 
the date first above written.

                                       ANALYTICAL SURVEYS, INC.


                                       By: 
                                          ------------------------------------
                                            Scott C. Benger
                                            Senior Vice President, Treasurer
                                            and Secretary

<PAGE>

                         ACQUISITION LOANS NOTE RECORD


                        LOANS AND PAYMENTS OF PRINCIPAL
                                       TO
              ACQUISITION LOANS NOTE OF ANALYTICAL SURVEYS, INC.
                             DATED JUNE [   ], 1998



<TABLE>
<CAPTION>

            Principal
            Amount of        Interest Rate         Principal         Unpaid
Date          Loan            (or Margin)         Amount Paid        Balance
----        ---------        -------------        -----------        -------
<S>         <C>              <C>                  <C>                <C>


</TABLE>