Mr. Justice Serrano Geyls
delivered the opinion of the Court.
In this condemnation proceeding the petitioners challenge certain rulings of the trial court regarding the admission of some of the evidence as well as the value it fixed on the condemned land. We shall examine the two problems separately.
I
First: As part of their evidence, the petitioners offered an opinion and judgment from the former Tax Court determining the assessment for tax purposes of certain lands [100]*100similar to the ones condemned herein. The trial court rejected it on the ground that the valuation involved was different from the one required to be established in the suit. It appears in the record as evidence offered but excluded.
Closely related to the former offer, is the one made by the petitioners of the testimony of an assessor from the Treasury Department who, with the pertinent documents at hand, was to testify on the appraisal of the condemned parcels made by the said Department for tax purposes. Relying on Rule 45 of the former Rules of Civil Procedure, the petitioners had obtained from the clerk of the court the issuance of a summons addressed to the Secretary of the Treasury or to his representative ordering these officials to appear in court to testify on the matters described above. The court did not permit the testimony of the witness and held that Rule 34 was applicable and that the petitioners had failed to meet the requisites of good cause and absence of any other remedy which it requires. In view of the considerations set forth below, it would be idle to decide this last procedural question.
The problem of the admissibility of the assessment of a property for tax purposes as evidence of the value of said property for other purposes has been considered in its manifold aspects in numerous cases. Valuation for taxation purposes as admissible to show value for other purposes, 39 A.L.R. 2d 209 (1955); Jahr, Eminent Domain 235-240 (1957) ; 1 Orgel, Valuation under the Law of Eminent Domain 629-645 (1953) ; 5 Nichols, Eminent Domain 313— 324 (1952). The overwhelming majority of courts in the United States has held that said assessed valuation is not competent direct evidence of the value of a property for purposes other than taxation. This rule has been consistently followed in condemnation proceedings in the federal courts as well as in the state courts. A very small minority has accepted the contrary view, but making it clear in many [101]*101cases, that the above-mentioned evidence, although ádmissible, is of little probative value. State v. Barbe, 24 So.2d 372, 378 (La. 1945); United States v. Phillips, 50 F. Supp. 454, 458 (D.C.Ga. 1943); Fort Worth & D.S. Ry. Co. v. Gilmore, 13 S.W.2d 416, 417 (Tex. 1929).
When it is the condemnor who tries to introduce the evidence of assessed valuation, the courts have refused to accept it adducing technical arguments based on the doctrines of hearsay evidence, res inter alios acta and the lack of participation on the part of the landowner in the assessment proceeding.1 Suffolk & C. Ry. Co. v. West End Land & Improvement Co., 49 S.E. 350, 351 (N.C. 1904); Girard Trust Co. v. City of Philadelphia, 93 Atl. 947, 948 (Pa. 1915); Kansas City & G. Ry. Co. v. Haake, 53 S.W.2d 891, 892-894 (Mo. 1932); United States v. Certain Parcels of Land, 261 F.2d 287, 289-291 (4th Cir. 1958). However, in this situation as well as when the owner of the property offers the evidence, the unreliability of said evidence as an index of market value, has been adduced with great emphasis together with the well-known fact that these assessed valuations serve several purposes and not merely the precise determination of the market value of the property. Savannah Sugar Refining Corp. v. Atlantic Towing Co., 15 F.2d 648, 650 (5th Cir. 1926); Bankers Trust Co. v. International Trust Co., 113 P.2d 656, 660 (Colo. 1941); State v. Barbe, supra at 373 (D.C. Cir. 1931); In re Northlake Ave., 165 Pac. 113, 114 (Wash. 1917); 5 Nichols, op. cit. at 316; Jahr, op. cit. at 235. The well-known doctrine that a determination made by a public official cannot bind the state in a sphere of official action beyond the domain of authority of said official has also been opposed to the land[102]*102owners’ petition. In re Northlake Ave., supra at 114. A federal court2 has convincingly stated this argument:
“The power of a tax official to bind the public is limited, and what he does for purposes of taxation, should not be binding upon the public, or prejudicial to the public interest, when other public officials are engaged in the performance of a very different public function in an unrelated field. Though the tax official may purport to use market value as the criterion of assessed value, his primary concern is with relative, not absolute, values, but however he exercises his judgment for purposes of a reasonable distribution of the tax burden, his act, as an extrajudicial declaration, may not circumscribe the interest of the public in the difficult process of determining just compensation for property taken for public use.”
It is now convenient to examine as briefly as possible some aspects of the system existing at present for the assessment of property for taxation purposes. By virtue of Act No. 117 of May 9, 1947 (Sess. Laws, p.. 262, 13 L.P.R.A. 431 et seq.) a system called “scientific assessment” was established in Puerto Rico, according to which a general assessment was made in 1951 and a re-appraisement in 1958-59.
The scientific assessment of property, both in Puerto Rico as well as in other jurisdictions, is not made for the purpose of determining the exact market value of real property. Section 2 of the above-cited Act directs the Treasurer “to establish valuation and assessment standards with such accuracy and scientific details as will permit the fixing of adequate and equitable rates of valuation of property for taxation purposes.” Section 3 [as amended by Act No. 37 of 1951] adds that: “The Treasurer shall classify and assess all real property in its actual and effective value by utilizing any of the methods and factors recognized with respect to property valuation and assessment, so that the assessments for each of the different types of property may [103]*103be uniform.” 3 The official publications indicate that the aims of the scientific assessment are to establish a fair valuation system for taxation purposes, the uniformity in the assessment and “unit values of assessment based on the market value of the property.” 4 It is obvious that the administrators of this system will continually have to make adjustments to reconcile these three objectives. Besides, it is a well-known fact that all tax systems are unavoidably sensitive to the economical and political necessities of the community they serve, and that this sensitivity inevitably increases in the case of assessment of real property, since the latter is the basis for the borrowing capacity of a state. For these reasons a well-known authority in the field of public finance states that the purpose of a scientific assessment system should not be to determine the actual value of the property, but to establish a reasonable and equitable basis for taxation. Taylor, The Economics of Public Finance 301 (1953). Contrary to the former view, the courts are required to make an intense and thorough search in condemnation proceedings in order to establish as precise as possible the market value of a determined property at the time the official taking takes place.
However, it may be stated that, even accepting the above-mentioned difference between the objectives of both types of valuation, the assessed valuation would still be of some [104]*104.service if it is the landowner who offers it as a minimum index of the market value of the property, which is to .be weighed together with other pertinent evidence. Cf. Louisiana Highway Commission v. Giaccone, 140 So. 286, 290 (La. 1932).
This proposition, of course, does not overcome some of the technical obstacles applicable to the assessed valuation which, as we have seen, have been indicated by the case law of the United States,5 but it does keep its validity where the landowner, as in the case at bar, offers the testimony -of an officer who participated in the assessment proceeding and not a mere certificate thereof. Therefore, we must examine the above-mentioned assessment proceeding.
The manner in which the assessment of 1951 was made by the employees in charge thereof has been described in •the following manner in an official publication:
“Many persons participate in the new system for the assessment of property, some doing one thing while others do other ■things, until the assessed value is fixed.
“Some prepare the tables of unit values after much study and investigation, others inspect the properties and note down in cards the measurements and other data about each property, others classify the property following all the details which appear in the cards, and finally, the cards come to the central office where another group of employees multiply the costs or ■unit values by the measurements or details which appear in the cards thereby obtaining the assessed valuation of the property.” 6
As it may be observed, the scientific assessment of a property is the result of a collective effort made by the employees of a government organization and not the work [105]*105of one person alone. Moreover, the “costs” or “unit values” which serve as a basis for determining the market value of the property were obtained after a thorough investigation at different sources, but particularly after long conversations with experts in that matter and on the advice offered by a committee appointed for those purposes. When a reappraisal of the property was made some six years later, “there was no need to again inspect minutely the properties one by one. The physical inventory of each property was already made when each property was assessed for the first time under the System of Scientific Assessment. It was only necessary to readjust the former values according to the change in values that had taken place during the last years.”7
Therefore, one person alone even in the case of an executive, of those who intervened in this complicated proceeding, would not be competent to offer testimony, of his own knowledge, regarding all the elements which integrate the assessed valuation, when the latter is offered as evidence of the value of the condemned property. To overcome this obstacle, it would be necessary to offer the testimony of all the persons who in one way or another have participated in this proceeding. In the hypothesis, although highly improbable, that this could be done, it would be necessary to reproduce in the [106]*106condemnation suit all the details of the assessed valuation proceeding. This evidence, of course, would have to be admitted from the landowner as well as from the condemnor.
In short, the system of real property assessment for taxation purposes does not seek a completely individualized valuation of each property in order to determine with the greatest possible accuracy its true market value, but on the contrary, is based on norms and standards of general application to properties which are similarly located, and it has other additional objectives and answers certain economic and political necessities which can have no weight whatever on a valuation for condemnation purposes. The final determination of that assessed valuation is the product of a complex proceeding in which numerous persons intervene directly. The scant light which this official determination or the testimony regarding it may shed in some isolated cases would not compensate in any way whatsoever the confusions and. delays— “a concession to the shortness of life,” as phrased by Holmes — which would necessarily result when the scalpel of cross-examination penetrates deeply into the complex anatomy of that system in order to extricate those elements which may be persuasive in a condemnation proceeding. This is a clear example of technically admissible evidence which should not be admitted for powerful reasons of a normative character.8
Besides, an examination of the applicable legal provisions reasserts that the Legislative Assembly was aware of the difficulties which we have described. Section 3 of the above-cited Act of 1947, as amended by Act No. 228 of May 5, [107]*1071950 (Sess. Laws, p. 580, 13 L.P.R.A. § 432) provides in. its last sentence that: “The returns, cards, plans, maps, photographs, schedule, charts, and all other documents and information obtained and used by the Secretary of the Treasury in classifying, valuating, and assessing property by the scientific method herein prescribed, shall be evidence and shall constitute prima facie proof, for taxation purposes, of the circumstances and of the assessed valuation of the property to which they refer, and as such shall be admitted as evidence by the courts of Puerto Rico; Provided, that the Secretary of the Treasury or any agent designated by him may testify on the information contained in such evidence and its relationship with the value of the said property to which it refers.” (Italics ours.) The legislative declaration which orders the limitation of this evidence to “taxation purposes” is subject to other legal provisions even in the taxation field itself. Thus, for example, in the case of inheritance and gifts taxes, the pertinent law authorizes the Secretary of the Treasury to order the appraisal of “all estates granted or the object of a grant, as the case may be, at their market value as of the date of the death or of the grant.” 13 L.P.R.A. § 895. It is known that that special assessment is made in all cases. In the field of income taxes, examples may be cited also of some special assessments which ought to be made at a certain time and for the purpose of obtaining the “market value” of certain specific properties.
For the reasons stated in the case law of the United States outlined above and of the realities of our system of assessment which we have described, we hold that the official determinations regarding the valuation for the purposes of [108]*108property taxation 9 and the documents or testimonies regarding these determinations do not constitute admissible evidence of the market value in condemnation proceedings. Therefore, the trial court did not commit the errors charged.
Second: The petitioners complain also of the action of the trial court in refusing to admit certain evidence offered by them of some allegedly similar sales and in accepting other submitted by the respondent. Before considering these points, it is necessary to offer a brief description of the condemned parcels.
The first or parcel A has an area of 1.1980 cuerdas and the second or parcel B of 4.9955 cuerdas. They are adjacent to each other and are located, with a front of 223 meters, at kilometer 23, hectometer 3 of State Highway No. 23 leading from Ponce to Guayanilla, at a distance of 400 meters from Villa Street and at about 200 meters from Roosevelt Avenue. In front of parcel B and on the other side of Highway No. 23 there is a part of an extension of the housing project known as Rosaly, a two-story building where there is a “lechonera,” bar and dancing, and three small frame houses of little value. In front of the condemned parcels there is also a sugar cane plantation covering around 200 meters up to a modern development built by the Fullana Corporation. They are bounded on the north by a private road of earth and gravel which separates them from the Baldorioty housing project, a development provided with a minimum of public services and occupied by persons of low income. They are bounded on the south and the west by an agricultural zone dedicated to the cultivation of sugar cane. About 150 meters from the southern part of the parcels there is a vocational school and about 400 meters therefrom lies the new athletic stadium of the city.
[109]*109The trial court also found that:
“For five cents a person can go from the condemned parcels to any place in the city of Ponce. They are relatively close to churches, hospitals, drugstores, schools, and to commercial and industrial establishments.
“Highway No. 23, which, as we mentioned above, runs in front of the condemned parcels, is 13 meters wide and asphalted.
“Both parcels have access to electric and telephone lines and to the aqueduct and sewer system, both of pluvial and contaminated waters, which run along said piece of road.
“At the time of the expropriation, there was also a concrete sidewalk, 3 meters wide, running all along parcel B from north to south for a length of 70 meters. Besides, in front of both parcels there were two fire hydrants in use.
“Both parcels are located at the road level. They have a flat topography with a slight unevenness towards the northwestern part which gives them a good natural drainage.
“At the time of the expropriation both parcels were devoted to the growth of sugar cane (like the lands belonging to the main properties from which they were segregated and by which they were bounded on the west and south). But the best use to which both condemned parcels could have been devoted was for the construction of a residential development. For this it would have been necessary to lay out streets and sidewalks, to extend the lighting, water and sewerage systems, and to incur in other development expenses at a cost of $2.25 or $2.50 per square meter.”
The petitioners sustain that the market value of the condemned parcels is $2 per square meter, while the respondents and the trial court appraised them at $0.75 per square meter.
In the first place, it is alleged that the court committed error in refusing to admit documentary evidence regarding a transaction which took place between Luciano Martiniano García and the Asilo de Damas. The parcel object of that transaction has an area and a topography similar to the ones of the condemned parcels and it lies relatively near them, but it is located in Villa Street, a zone of great commercial and industrial development and surrounded by important establishments. Because of this essential difference in loca[110]*110tion the documentary evidence was not admitted. In so •doing, the court acted correctly. Housing Authority v. Viera, 72 P.R.R. 683/687-88 (1951); Commonwealth v. Bravo, 79 P.R.R. 732, 737 (1956).
There was no error either in rejecting two documents •offered by the defendants which contained copies of the judgments rendered by the Superior Court, Ponce Part, in condemnation proceedings against parcels allegedly similar to the ones examined in the case at bar. In People v. Colón, 73 P.R.R. 531, 540-41 (1952), we explained the reasons ■why this evidence is not admissible.
The petitioners also object to the rulings of the court .admitting a sale from the Ponce Cement Corp. to the Fullana Corp., another from Telares de Puerto Rico, Inc. to the Industrial Development Company, and another from La Reparada Development Co. to the Long Construction Co. In synthesis, they sustain that there are important differences in area, location, facilities, conditions of the soil, etc., between the parcels involved in those transactions and the condemned parcels which precluded the admission of the former as .similar sales. The court did not mention in its findings the .sales made by Telares 10 and La Reparada, wherefore we must conclude that it did not give them any weight whatsoever. Although the property sold by the Ponce Cement Corp. to the Fullana Corp. is different from the condemned parcels in several aspects,11 the court certainly did not abuse its powers in admitting the bill of sale.
II
The petitioners challenge the value assigned by the court to the condemned parcels, since they believe that [111]*111its weighing of the evidence was erroneous. They object the specific consideration given to certain elements as well as the general weighing of the entire evidence admitted.
First: Regarding the first aspect, the initial objection refers to a sale of a parcel of land made by the Ponce Cement Corp. to the Industrial Development Company at $4,500 per cuerda, little less than a month before the taking of the parcels expropriated by the state. It was admitted as a similar sale, but when rendering its judgment, the court refused to consider it because “as stated by defendants’ expert himself, the best use for this parcel was for industrial purposes.”
The parcel in question has an area of 3.39 cuerdas and is located in the ward of Canas,12 about 1.7 kilometers from the condemned parcels. It is very similar to the latter in area, topography, quality of the soil, in transportation, electricity and water facilities and in the access it has to other public services and commercial establishments. From all the transactions admitted, it is the one closer to the date of the expropriation. It is located further away from the center of the city than the condemned parcels and it has the disadvantage that it does not abut on the road, for which reason an alley must be used in order to get there.
We hold that the trial court erred in not granting any probative value whatsoever to this sale for the mere fact that the best use for the parcel “was for industrial purposes,” while the best use for the condemned parcels was residential. This is without doubt an important difference which should be given the consideration it deserves, but in view of the remarkable similarities indicated above, it is not in itself sufficient to reject this evidence, specially when it was established that the condemned parcels were susceptible of being used for an industry, and that no official prohibition [112]*112of such use existed at the time of the taking.13 Cf. Commonwealth v. Ocean Park Development Corp., 79 P.R.R. 149, 161-63 (1956).
The court admitted a sale from the Porto Rico Iron Works to the Puerto Rico Housing Authority, but in its findings it decided that, although it “was sufficiently similar” to the condemned parcels, it could not give “great weight” to this transaction because “(a) the buyer had the power to expropriate, (b) the existence of a special necessity or convenience on the part of the buyer could be inferred from the contiguity of said lands to the Ponce de León housing development and (c) the parcel has two fronts, one facing Highway No. 23 and another facing Roosevelt Avenue, which is a first-rate avenue.” The parcel in question has an area of 13.1225 cuerdas and is located in front of the condemned parcels, on the other side of the road. In 1946 it was sold at $5,109 per cuerda. Its topography, facilities and access are similar to those of the condemned parcels but its soil is of an inferior quality (saltpetrous, “swampy”) and it is in part adjacent to the slum Palo de Pan and to the railway track.
In Puerto Rico Housing Authority v. Valldejuli, 71 P.R.R. 600, 602 (1950) we held that sales to an entity which has the power of condemnation “must be scrutinized more closely than those to persons not possessing the power to condemn. And the burden is on the person offering them to show they [113]*113were free and voluntary, although aided by the presumption that like other sales they were not under compulsion. But once they are found to be voluntary, they must be treated like other sales; i.e., they must be admitted if found to be contemporaneous sales of similar property.”
The defendants offered the testimony of Mr. Luis Ferré, vice-president of the company making the sale, who stated in synthesis that the sale had been completely voluntary, that there had been no pressure or threats of condemnation, that the conversations lasted for several weeks and that originally a higher price was asked but that later, when the purpose for which the parcel was being purchased was revealed, a reduction was made. We believe that this uncontroverted testimony is in accordance with the rule established in the Validejuli case, that it shows that the sale was voluntary 14 and that it considerably weakens the argument of the “special purchaser.” Besides, the last two factors mentioned by the court are set-off in part by the advantages we already pointed out that the condemned parcels had over the one sold by the Porto Rico Iron Works, and by the general rise in the valuation of land in the city of Ponce from 1946 to 1951. We find, therefore, that the court erred in not giving any weight whatsoever to this sale.15 As we shall see hereafter, this is actually what it did.
[114]*114The court admitted documentary evidence regarding the Sale of a parcel of land made by Arturo Febry to La Rambla Development Corp. in 1948 for the sum of $5,158.12; but finally it decided not to give it "any probative weight whatever” because "aside from the difference in area between this parcel and the condemned lands, the purchaser acquired said parcel to enlarge the La Rambla Development” and for that reason it was a “special purchaser.” 16 The parcel sold by Mr. Febry has an area of 1716.04 square meters and is located at one end of Ponce, opposite to the one where the condemned parcels are situated, and about three kilometers from the center of the city. The zones are, however, very similar, as well as the topography, facilities, services and access of the parcels and the best use to which they could be devoted. Unlike the condemned parcels, the parcel sold by Mr. Febry did not have access to the sewerage system. Although the reasons which the court had are meritorious, we do not believe, after the other circumstances have been considered, that they can destroy by themselves the entire value of his evidence. It should have been given some weight.
The court also admitted three sales of lots located in the vicinity of the condemned parcels and gave them weight as an indication of the value of the lots in the zone but not as “an adequate indication of the value of the condemned parcels” since they are “isolated lots which do not form a part of an urban development and their limited area increases their unitary value.” One of the lots measured 984 square meters and had been sold in 1948 at $1.52 per square meter; another had 707.84 square meters and had been sold in 1950 at $3.18 per square meter, while an adjacent lot of 638.75 square meters was sold in the same transaction [115]*115at $2.81 per square meter; and another of 3,377.61 square meters had been sold some months prior to the expropriation at $2:72 per square meter. Aside from their area, the lots are very similar to the condemned parcels regarding all their other characteristics.17
- It is impossible to determine the persuasive effect which a' sale considered as an “indication of the value of the lots in the zone” may have in opposition to the same sale considered as an “indication of the value of the condemned lands” in the mind of a judge.18 We shall not attempt to determine it. In any case, it is necessary to remember that in several cases we have affirmed rulings of the trial courts which admitted and gave weight to, as evidence of similar sales, certain transactions involving parcels of land which had great differences in area with the ones condemned in said cases, but which were similar to them in other aspects.19
Second: The petitioners challenge the general weighing of the evidence on the ground that the court gave a decisive weight, in the aspect of similar sales,20 to two [116]*116transactions made on September 29, 1950 between the Ponce Cement Corp. and the Fullana Corp., and that it practically rejected all other evidence. The petitioners are correct.
The above-mentioned transactions involve two parcels of land sold to the Fullana Corp., one of 25.876 cuerdas at $2,500 per cuerda and another of 29.451 cuerdas at $3,400 per cuerda. Besides the price paid therefor, the purchaser bound itself to “pave with cement” 21 all the streets of the development to be constructed, and to build on its own account, and “also of cement,” the extension of the streets of said development up to a parcel belonging to the vendor, reserved for the construction of an avenue, and across a strip of land 40 meters wide belonging also to the vendor. There is no evidence in the record as to the amount of this obligation, but doubtlessly its performance must have resulted in considerable benefit to the vendor. Furthermore, the purchaser had to acquire a lot and a building located on Hostos Avenue in order to provide an outlet for the parcels.
The parcels mentioned above are located about 150 meters from the condemned lands. They are similar to the latter in topography, facilities, access and most suitable use of the lands. They are at an advantage over them with regard to location, since they are closer to the Mariani Development and to the campus of the Santa Maria University, but at the same time they are at a disadvantage with regard to certain aspects. They are adjacent on one side to the slum Palo de Pan and on the other side to the railway terminal, which, in the judgment of the experts, reduces their value for residential purposes. At one end they have a ditch or gully, which also has an unfavorable effect on their price. The electricity, water and sanitary services of the city are not directly in front of them as in the case of the condemned parcels, but they are situated in the Mariani Development [117]*117and Hostos Avenue, and this requires additional expenses in order to gain access thereto. They do not have access to the telephone lines. In short, although the sale of these parcels was correctly admitted as evidence of a contemporaneous sale of similar property, we do not believe that they should have been given the decisive and practically conclusive weight which the trial court granted them. The great difference in area between them and the condemned parcels,22 the peculiarities of the selling “price” and the other elements we have described rather suggested that a relative merit be given to them jointly with the other transactions which could enlighten the mind of the judge.
We are aware that there are no two identical properties and that the comparative method only requires similarities and not equality. For this and other reasons, in cases of this sort, we rely as a general rule, on the exercise of the well-informed discretion of the trial court, who has the opportunity of gauging at a closer distance than we do, the different elements which should integrate a valuation judgment. And we have repeatedly held that we shall not intervene with that discretion, even when the court has erred in some rulings regarding the admission of evidence, provided its valuation judgment finds sufficient support in the evidence admitted. Commonwealth v. Bravo, supra at 739; P. R. Housing Authority v. Colón, 73 P.R.R. 208, 213 (1952); People v. Carmona, supra at 296; People v. Lamboglia, 70 P.R.R. 773, 779 (1950). However, we believe that in the ease at bar the judge unreasonably limited the scope of his final search to practically only one of the similar sales and that he unnecessarily rejected several others of similar per[118]*118suasive force. Similar sales constitute, as we know, the best evidence of market- value in condemnation proceedings. P. R. Housing Autohrity v. Valldejuli, supra at 603. In the case at ba,r there is practically no other evidence, because the one regarding the land market in the city of Ponce is by its general character, of a complementary nature, and because the valuation criteria of the experts of both parts were mainly based on the authority which each one gave to the similar sales.23
We are convinced, in view of the reasons already stated, that the trial court committed “manifest error” in the weighing of the evidence and that its ruling was prejudicial to the right of the petitioners to receive a fair compensation for the condemned parcels. Cf. P. R. Housing Authority v. Valldejuli, supra at 603. Therefore, the record will be .remanded to the trial court with instructions to make new findings of fact and conclusions of law in the light of the views stated in this opinion and that a new judgment be rendered.
The judgment appealed from is reversed and the case remanded for further proceedings not inconsistent with this opinion.
It is not necessary, of course, to decide in this case whether or not evidence of valuation for purposes of property taxation is admissible in cases related to other taxes.